NCTS-PH/2004

Two-Higgs-Doublet Model with Soft CP-violation Confronting Electric Dipole Moments and Colliders

1, 2, 3, 3, 1, 4, Kingman Cheung, ∗ Adil Jueid, † Ying-nan Mao, ‡ and Stefano Moretti § 1Physics Division, National Center for Theoretical Sciences, Hsinchu, Taiwan 300 2Department of Physics, National Tsing Hua University, Hsinchu, Taiwan 300 3Division of Quantum Phases and Devices, School of Physics, Konkuk University, Seoul 143-701, Republic of Korea 4School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ, United Kingdom

We analyze CP-violating effects in both (EDM) measurements and future analyses at the Large Hadron Collider (LHC) assuming a Two-Higgs-Doublet Model (2HDM) with “soft” CP-violation. Our analysis of EDMs and current LHC constraints shows that, in the case of a 2HDM Type II and Type III, an (0.1) CP-violating phase O in the Yukawa interaction between H1 (the 125 GeV Higgs boson) and fermions is still

allowed. For these scenarios, we study CP-violating effects in the EDM and ttH¯ 1 production at the LHC. Our analysis shows that such an (0.1) CP-violating phase can O be easily confirmed or excluded by future neutron EDM tests, with LHC data providing a complementary cross-check.

I. INTRODUCTION

CP-violation was first discovered in 1964 through the KL ππ rare decay channel [1]. Later, → more CP-violation effects were discovered in the K-, B-, and D-meson sectors [2, 3] and all the discovered effects are consistent with the explanation given by the Kobayashi-Maskawa (KM) arXiv:2003.04178v2 [hep-ph] 23 Oct 2020 mechanism [4]. However, the KM mechanism itself cannot generate a large enough matter- antimatter asymmetry in the Universe. Therefore, new CP-violation sources beyond the KM mechanism are needed to explain the latter [5–7]. Experimentally, all the discovered effects of CP-violation till now have appeared in flavor physics measurements, yet they can also be tested through other methods. These can generally be divided

[email protected][email protected][email protected] §[email protected] 2 into two different categories: (a) indirect tests, which can merely probe the existence of CP- violation but cannot confirm the source(s) behind it; (b) direct tests, which can directly lead us to the actual CP-violation interaction(s). For indirect tests, there is a typical example that one most often uses, the Electric Dipole Moment (EDM) measurements [8–13]. The reason is that the EDM effective interaction of a fermion is

i µν 5 = df fσ¯ γ fFµν, (1) LEDM −2 wherein df is the EDM of such a fermion f, which leads to P- and CP-violation simultaneously [9]. It is a pure quantum effect, i.e., emerging at loop level and, in the (SM), the electron and neutron EDMs are predicted to be extremely small [9],

SM 38 SM 32 d 10− e cm, d 10− e cm, (2) | e | ∼ · | n | ∼ · because they are generated at four- or three-loop level, respectively. Thus, since the SM predictions for these are still far below the recent experimental limits [14–17]

29 26 de < 1.1 10− e cm, dn < 1.8 10− e cm, (3) | | × · | | × · both given at 90% Confidence Level (C.L.)1, these EDMs provide a fertile ground to test the possibility of CP-violation due to new physics. In fact, in some Beyond the SM (BSM) scenarios, the EDMs of the electron and neutron can be generated already at one- or two-loop level, thus these constructs may be already strictly constrained or excluded. In measurements of de and dn, though, even if we discover that either or both EDMs are far above the SM predictions, we cannot determine the exact interaction which constitutes such a CP-violation. For direct tests, there are several typical channels to test CP-violation at colliders. For instance, measuring the final state distributions from top pair [18–31] or τ pair [32–40] production enables one to test CP-violating effects entering the interactions of the fermions with one or more Higgs bosons. The discovery of the 125 GeV Higgs boson [41–43] makes such experiments feasible. Indeed, if more (pseudo)scalar or else new vector states are discovered, one can also try to measure the couplings amongst (old and new) scalars and vectors themselves to probe CP-violation entirely from the bosonic sector [44–46]. At high energy colliders, the discovery of some CP-violation effects

1 −26 An earlier result [15, 16] is |dn| < 3.0 × 10 e · cm while a most recent measurement by the nEDM group [17] −26 set a stricter constraint |dn| < 1.8 × 10 e · cm, both at 90% C.L. At 95% C.L., the latest constraint is then −26 |dn| < 2.2 × 10 e · cm. 3 can lead us directly to the CP-violating interaction(s), essentially because herein one can produce final states that can be studied at the differential level, thanks to the ability of the detectors to reconstruct their (at times, full) kinematics, which can then be mapped to both cross section and charge/ asymmetry observables. Theoretically, new CP-violation can appear in many new physics models, for example, those with an extended Higgs sector [47–52]. Among these, we choose to deal here with the well known Two-Higgs-Doublet Model (2HDM) [51], which we use as a prototypical source of CP- violation entertaining both direct and indirect tests of it. In 2HDM, another Higgs doublet brings four additional scalar degrees of freedom, and two of which are neutral. Thus there are totally three neutral (pseudo)scalars. In the CP-conserving case, two of them are scalars and one is a pseudoscalar. While for some parameter choices, the pseudoscalar can mix with the scalar(s), and then CP-violation happens. Specifically, the 2HDM with a Z2 symmetry is used here, in order to avoid large Flavor Changing Neutral Currents (FCNCs), yet such a symmetry must be softly broken if one wants CP-violation to arise in this scenario [51]. The CP-violation effects in 2HDM were widely studied in recent years. People carefully calculated the EDMs in 2HDM and discussed their further phenomenology [53–66]. Usually, the domain contributions come from the two-loop Barr-Zee type diagrams [53], and complex Yukawa interactions provide the CP-violation sources. Especially, for the electron EDM, a cancellation between different contributions may appear in some region [67–74], thus a relative large CP-phase (0.1) in the Yukawa interactions will still be allowed. Such a CP-phase is helpful to explain ∼ O the matter-antimatter asymmetry in the Universe [69, 74–77]. However, such cancellation usually does not appear in the same region for neutron EDM, thus the future measurements on neutron EDM will be helpful for testing the CP-phases, which will be discussed in details below. The collider studies for CP-violation were usually performed model-independently, but the results can be simply applied for 2HDM. We will therefore study the effects of such a CP-violating 2HDM onto electron and neutron EDMs as well as processes entering the Large Hadron Collider (LHC), specifically, those involving the production of a top-antitop pair in association with the 125 GeV Higgs boson. This paper is organized as follows. In section II, we review the construction of the 2HDM with so-called “soft” CP-violation with the four standard types of Yukawa interactions. Then, in section III, we discuss the current constraints from electron and neutron EDMs, show the reason why we eventually choose to pursue phenomenologically only the 2HDM Type II and Type III for our collider analysis and discuss the importance of future neutron EDM tests. In section IV, we 4 discuss the current constraints from collider experiments on these two realizations of a 2HDM. In section V, we discuss LHC phenomenology studies on CP-violation effects in the ttH¯ 1 associated production process. Finally, we summarize and conclude in section VI. There are also several appendices which we use to collect technical details.

II. MODEL SET-UP

In this section, we briefly review the 2HDM with a softly broken Z2 symmetry and how CP- violation arises in such a model. We mainly follow the conventions in [78–80]. The Lagrangian of the scalar sector can be written as

µ = (Dµφi)†(D φi) V (φ , φ ). (4) L − 1 2 i , X=1 2 Under a Z transformation, we can have φ φ , φ φ , thus, in the scalar potential, all 2 1 → 1 2 → − 2 terms must contain even numbers of φi. However, if the Z2 symmetry is softly broken, a term

φ†φ is allowed, thus the scalar potential becomes ∝ 1 2 2 2 1 2 2 2 1 V (φ , φ ) = m φ†φ + m φ†φ + m φ†φ + H.c. + λ φ†φ + λ φ†φ 1 2 −2 1 1 1 2 2 2 12 1 2 2 1 1 1 2 2 2 h  i       λ5 2 +λ φ†φ φ†φ + λ φ†φ φ†φ + φ†φ + H.c. . (5) 3 1 1 2 2 4 1 2 2 1 2 1 2             Here φ1,2 are SU(2) scalar doublets, which are defined as

+ + ϕ1 ϕ2 φ1 , φ2 . (6) ≡  v1+η1+iχ1  ≡  v2+η2+iχ2  √2 √2     2 2 The parameters m1,2 and λ1,2,3,4 must be real, while m12 and λ5 can be complex. Further, v1,2 are the Vacuum Expectation Values (VEVs) of the scalar doublets with the relation v 2 + v 2 = | 1| | 2| 2 3 246 GeV. The ratio v /v may also be complex , and we define tβ v /v as usualp . 2 1 ≡ | 2 1| 2 As was shown in [51], CP-violation in the scalar sector requires a nonzero m12. For the three 2 possible complex parameters m12, λ5, and v2/v1, we can always perform a field rotation to keep at least one of them real. In this paper, we choose v2/v1 to be real (thus both v1,2 are real) like in [78–80], and have the relation

2 Im(m12) = v1v2Im(λ5) (7)

2 We can always fix v1 real through gauge transformation and v2 may be complex at the same time. 3 In this paper, we denote sα ≡ sin α, cα ≡ cos α, and tα ≡ tan α. 5

2 following the minimization conditions for the scalar potential. If Im(m12) and Im(λ5) are non-zero, CP-violation occurs in the scalar sector. We diagonalize the charged components as

+ + G cβ sβ ϕ = 1 , (8)  +     +  H sβ cβ ϕ − 2       where H+ is the charged Higgs boson and G+ is the charged Goldstone. Similarly, for the CP-odd neutral components,

0 G cβ sβ χ1 = , (9)       A sβ cβ χ − 2       where A is the physical CP-odd degree of freedom and G0 is the neutral Goldstone. In the CP- conserved case, A is a pseudoscalar boson while, in the CP-violating case, A has further mixing with the CP-even degrees of freedom as

H1 η1     H2 = R η2 . (10)      H3   A          Here H1,2,3 are mass eigenstates and we choose H1 as the lightest one with mass m1 = 125 GeV, so that it is the discovered SM-like Higgs boson. The rotation matrix R can be parameterized as

1 cα2 sα2 cβ+α1 sβ+α1       R = cα sα 1 sβ α cβ α . (11) 3 3 − + 1 + 1        sα3 cα3   sα2 cα2   1   −   −          When α , 0, H becomes the SM Higgs boson. If m , , α , , and β are known, m can be 1 2 → 1 1 2 1 2 3 3 expressed as [62, 65, 80] 2 2 2 2 2 2 (m1 m2sα3 )c2β+α1 /cα3 m2s2β+α1 tα3 m3 = − − . (12) c β α sα s β α tα 2 + 1 2 − 2 + 1 3 In the mass eigenstates, the couplings between neutral scalars and gauge bosons can be parameterized via

2 2 3 2mW +,µ mZ µ cijg µ µ cV,iHi W Wµ− + Z Zµ + Zµ(Hi∂ Hj Hj∂ Hi). (13) L ⊃ v v 2cθ − 1 i 3   i=1 W ≤X≤ X The coefficients are then

cV,1 = c23 = cα1 cα2 , (14)

cV, = c = cα sα cα sα sα , (15) 2 − 13 − 3 1 − 1 2 3

cV, = c = sα sα cα cα sα . (16) 3 12 1 3 − 1 3 2 6

Next we turn to the Yukawa sector. Due to the Z2 symmetry, a fermion bilinear can couple to only one scalar doublet, with the form Q¯LφiDR, Q¯Lφ˜iUR, or L¯Lφi`R, thus it is helpful to avoid the FCNC problem [51]. Here φ˜i iσ φ and left-handed fermion doublets are defined as ≡ 2 i∗ T T Qi,L (Ui,Di) and LL (νi, `i) , for the i-th generation. Since the scalar potential contains a ≡ L ≡ L φ φ exchange symmetry, we can set the convention in which Q¯LUR always couple to φ so 1 ↔ 2 2 that there are four standard types of Yukawa couplings [51, 80]:

YU Q¯Lφ˜ UR YDQ¯Lφ DR Y`L¯Lφ `R + H.c., (Type I), − 2 − 2 − 2  YU Q¯Lφ˜2UR YDQ¯Lφ1DR Y`L¯Lφ1`R + H.c., (Type II),  − − − (17) L ⊃  ¯ ˜ ¯ ¯  YU QLφ2UR YDQLφ2DR Y`LLφ1`R + H.c., (Type III),  − − − ¯ ˜ ¯ ¯  YU QLφ2UR YDQLφ1DR Y`LLφ2`R + H.c., (Type IV).  − − −  The fermion mass matrix is Mf = Yf vcβ/√2 if the fermion couples to φ1 and Mf = Yf vsβ/√2 if it couples to φ2. We parameterize the Yukawa couplings of mass eigenstates as

mf cf,iHif¯LfR + H.c. . (18) L ⊃ − v i,f X  For CP-violating models, cf,i are complex numbers and we list them in section A for all four types of Yukawa interactions. In all these models, Im(cf, ) sα , thus α is an important mixing angle 1 ∝ 2 2 which measures the CP-violating phase in the Yukawa couplings of H1.

III. CURRENT EDM CONSTRAINTS AND FUTURE TESTS

In this section, we analyze the EDM constraints of the electron and neutron for the four types of 2HDM in some detail. The b sγ decay requires the charged Higgs mass to be m ± 600 GeV → H & for all the four types of Yukawa couplings when tβ 1 [81–84]. If tβ gets larger, the constraints ∼ will become weaker for Type I and III Yukawa couplings. The oblique parameters [85, 86] will then 4 favor the case mH2,3 & 500 GeV [87–90] . With such choices for the scalar masses, the vacuum 2 2 2 2 stability condition favors µ Re(m )/s β (450 GeV) [79]. Notice that µ will modify the ≡ 12 2 . charged Higgs couplings a little, but it is not numerically important to the EDM calculation, so we fix it at µ2 = (450 GeV)2 in the rest of this work. More discussions about the scalar couplings will appear in section B. An electron EDM measurement places a very strict constraint on the complex Yukawa couplings in most models. As a rough estimation, if we consider CP-violation only in the 125 GeV Higgs

4 When H1 is SM-like, the oblique parameter constraints are sensitive mainly to the mass splitting between the charged and neutral scalars. They are not sensitive to the mixing parameters in Equation 11. 7

3 interaction with the top , the typical constraint is arg(ct,1) . 10− [73]. However, some models (including the 2HDM) allow for the accidental cancellation among various contributions, so that larger arg(ct,1) may still be allowed [67–74]. In such cases, neutron EDM constraints will also become important, as shown in the analysis later in this section.

A. Electron EDM

A recent electron EDM measurement was performed using the ThO molecule [14]. The exact constrained quantity is

eff 29 d de + kC < 1.1 10− e cm. (19) | e | ≡ | | × · The second term measures the contribution from CP-violating electron-nucleon interactions via

C NN¯ e¯iγ5e , (20) L ⊃   where the coefficient C is almost the same for proton and neutron. Here, k 1.6 10 15 GeV2e ≈ × − · cm, which was obtained for ThO [91, 92], however, for most other materials with heavy atoms, this quantity appears to be of the same order [9, 93]. The contribution from electron-nucleon interactions is usually sub-leading, though it can also become important. The typical Feynman diagrams contributing to the electron EDM in the 2HDM are listed in

Figure 1. Diagrams (a)-(e) are Barr-Zee type diagrams [53] with the top quark t, W ±-boson, or charged Higgs H± in the upper loop, while diagrams (f) and (g) are non-Barr-Zee type. Such seven diagrams contribute directly to de. Diagram (h) shows the contribution through the electron-quark interaction, while diagram (i) shows the contribution through the electron-gluon interaction. The contributions can be divided into eight parts as summarized in Table I. The analytical expressions in the Feynman-’t Hooft gauge are listed below. For simplicity we denote

√2meGF αem 14 28 δ = 3.1 10− GeV = 6.1 10− e cm (21) 0 ≡ (4π)3 × × · from now on. For the fermion-loop contribution in which the top quark is dominant, we have [53–59, 63, 66, 67]

t,γ,Hi de 32 = δ [f(ztH )Re (ct,i) Im (ce,i) + g(ztH )Re (ce,i) Im (ct,i)] , (22) e 3 0 i i 8s2 θW 2 t,Z,Hi 1 3 ( 1 + 4sθ ) de − − W =   δ e − s2 c2 0 × θW θW

[F (ztHi , ztZ )Re (ct,i) Im (ce,i) + G(ztHi , ztZ )Re (ce,i) Im (ct,i)] . (23) 8

FIG. 1: Typical Feynman diagrams contributing to the electron EDM in the 2HDM. The blue lines can be γ or Z while red lines are neutral Higgses H1,2,3. Diagrams (a)-(g) will contribute to de directly while diagrams (h)-(i) will contribute to the electron-nucleon interaction term. γ γ γ

t W H±

e e e e e e (a) (b) (c)

γ γ γ

W H± W H W ± W

νe νe νe e e e e e e (d) (e) (f)

γ g g q q Q

e

Z Z e e e e e e (g) (h) (i)

2 2 2 Here zij m /m and θW is the weak mixing angle with s = 0.23. The loop integration functions ≡ i j θW here and below are all listed in section C. For the electron EDM calculation, the Z-mediated contribution is accidentally suppressed by 1/2 + 2s2 0.04. For the W -loop contribution, we − θW ∼ − have [53–55, 57–59, 63, 66]

W,γ,Hi de = δ0 12f(zWHi ) + 23g(zWHi ) + 3h(zWHi ) e − " 2 + (f(zWHi ) g(zWHi )) cV,iIm (ce,i) , (24) zWHi − # W,Z,Hi 1 + 4s2 5 t2 7 3t2 de θW θW 2 θW 2 3 = − δ − F (zWH , c ) + − G(zWH , c ) + h(zWH ) e s2 0 2 i θW 2 i θW 4 i θW " 3 1 t2 − θW 2 2 + g(zWHi ) + F (zWHi , cθW ) G(zWHi , cθW ) cV,iIm (ce,i) . (25) 4 4zWHi − #  9

TABLE I: Different contributions to the electron EDM and the corresponding Feynman diagrams.

Diagram Contribution CP-violation vertex

t,γ/Z,Hi de (a) Fermion (top) loop Hiee¯ , Hitt¯

W,γ/Z,Hi de (b) W -loop Hiee¯

H±,γ/Z,Hi ± de (c) Charged Higgs H loop Hiee¯

W,H±,Hi ± ± ± ∓ de (d) and (e) W -H -loop H W Hi W δde (f) non-Barr-Zee W -loop Hiee¯ Z δde (g) non-Barr-Zee Z-loop Hiee¯ int de,q,i (h) Electron-quark interaction Hiee¯ int de,g,i (i) Electron-gluon interaction Hiee¯

This contribution will cross zero around mi 500 GeV because of the cancellation between W and ∼ Goldstone contributions and, in the heavy mi limit, the pure Goldstone diagram has the behavior ln(m2/m2 ). The charged Higgs loop contributions are [57] ∼ i W ± H ,γ,Hi 2 de 2δ0v = [f(z ,i) g(z ,i)] c ,iIm (ce,i) , (26) e − m2 ± − ± ±   ± ± dH ,Z,Hi 1 + 4s2 2δ v2 e − θW 0 = 2 [F (z ,i, z ,Z ) G(z ,i, z ,Z )] c ,iIm (ce,i) . (27) e s2θW t2θW m ± ± − ± ± ±  ±  Hereafter, “ ” is used to denote the charged Higgs boson while c ,i is the coupling constant between ± ± + the charged and neutral scalars entering via c ,ivHiH H−. The W ±-H± associated loop L ⊃ − ± yields [57]

± W,H ,Hi a a b b de δ0 Hi (zWHi ) Hi (z ,i) Hi (zWHi ) Hi (z ,i) ± ± = 2 − cV,i − c ,i Im (ce,i) . (28) e −2sθ z ,W 1 − z ,W 1 ± W  ± − ± −  The first term corresponds to diagram (d) while the second term corresponds to diagram (e). The non-Barr-Zee type diagrams give [55, 63]5

W,Hi de δ0 a b c d e = 2 DW,i + DW,i + DW,i + DW,i + DW,i cV,iIm (ce,i) , (29) e −sθ W   Z,Hi de 2 a b c = 4δ t D + D + D cV,iIm (ce,i) . (30) e − 0 θW Z,i Z,i Z,i   The analytical expressions are too lengthy to present them here so that we list all of them in 3 section C. One-loop contributions to de are highly suppressed by me and thus we ignore them

5 We have checked the results in [55] and [63]. In the heavy mi limit, the loop functions should be logarithm enhanced as in [55] (just like the pure Goldstone contribution in [54]). However, the results in [63] have improper power enhancement thus this behavior cannot be physical. So we used for validation the result in [55]. 10

[70, 94]. The interaction induced effective EDM terms are [92, 95–97]

√ int 2meGF k ¯ de,q,i = 2 Im(ce,i) Re(cu,i) muuu¯ + Re(cd,i) mddd + msss¯ , (31) mi h i h i   int √2meGF k αs µν de,g,i = 2 Im(ce,i) [2Re(cu,i) + Re(cd,i)] GµνG . (32) − 3mi 4π D E The nucleon matrix elements N N and their values are similar for proton and neutron. hOi ≡ h |O| i Thus we choose the average values of proton and neutron considering three active (u, d, s) at the hadron scale 1 GeV [97–103], as listed in Table II. Summing all parts together, the effective ∼

TABLE II: Nucleon matrix elements in the 3-flavor scheme at the hadron scale 1 GeV. The lattice ∼ calculation of quark matrix elements are a bit different from different groups as summarized in [103], and the results in this table were quoted from [101] which are closed to the averaged values. The gluon matrix element was derived based on [98]. m uu¯ m dd¯ m ss¯ αs G Gµν h u i d h s i 4π µν 14.5 MeV 31 .4 MeV 40.2 MeV 183 MeV − electron EDM is

eff int de = de + de

± ± ± t,γ,Hi t,Z,Hi W,γ,Hi W,Z,Hi H ,γ,Hi H ,Z,Hi W,H ,Hi = de + de + de + de + de + de + de

W Z int int +δde + δde + de,q,i + de,g,i. (33)

j For each part above, de me thus it is suppressed by the small electron mass. We can extract ∝ j j Ce de/( me), which is independent of the fermion mass. This coefficient is not useful in the ≡ − electron EDM calculation, but it will be helpful in order to map the corresponding part into the quark EDM, which is important in the neutron EDM calculation below.

B. Neutron EDM

The neutron EDM calculation is more complex as it involves more contributions and QCD effects. As shown in Figure 2, there are three types of operators contributing to the neutron EDM, 6 including the quark EDM operator q, quark CEDM operator ˜q and Weinberg operator g . O O O

6 ± In 2HDM with Z2 symmetry, there is no CP-violation entering the tbH -vertex, thus we do not need to consider the diagram with a charged Higgs boson inside the loop for Weinberg operator [56]. 11

FIG. 2: Various contributions to the neutron EDM: quark EDM, quark Color EDM (CEDM) and Weinberg operator. γ g g

q q q q g g (a) (b) (c)

They are chosen as follows [9, 58]:

i µν q = eQqmqqσ¯ γ qFµν, (34) O −2 5 i µν a a ˜q = gsmqqσ¯ t γ qG , (35) O −2 5 µν 1 abc a b,ρ c,µν g = gsf G G G˜ , (36) O −3 µρ ν

a abc where gs is the QCD coupling constant, t is a generator of the QCD group and f denotes a QCD structure constant. At a scale µ,

Cq(µ) q(µ) + C˜q(µ) ˜q(µ) + Cg(µ) g(µ) (37) L ⊃ O O O q u,d X=   and

dq(µ)/e Qqmq(µ)Cq(µ), d˜q(µ) mq(µ)C˜q(µ). (38) ≡ ≡

For convenience we also redefine w(µ) gs(µ)Cg(µ). Notice that these EDMs should be first ≡ calculated at the weak scale µW mt. ∼ The calculation methods of Cu and Cd are the same as those for de through diagrams (a)-(g) in Figure 1. For the quark EDM, we perform the calculation at the weak scale µW mt and list ≈ 12

j the results of the Cq evaluation [57] as follows:

± ± t/W/H ,γ,Hi Z ¯t/W/H ,γ,Hi ¯Z Cq , δCq = Ce , δCe , (39)    2s2  1 θW t/W/H±,Z,H + 1 ± i − 2 3 ¯t/W/H ,Z,Hi Cd = 1 2 − Ce , (40) + 2s · Qd − 2 θW 4s2 1 θW ± 1 ± t/W/H ,Z,Hi 2 − 3 ¯t/W/H ,Z,Hi Cu = 1 2 − Ce , (41) + 2s · Qu − 2 θW ± 1 ± 1 W,H ,Hi W ¯W,H ,Hi ¯W Cu , δCu = Ce , δCe , (42) Qu Qu     ± 1 ± 1 W,H ,Hi W ¯W,H ,Hi ¯W Cd , δCd = − Ce , − δCe . (43) Qd Qd     j j Here, each C¯e means Ce with a replacement ce,i cq,i in the Yukawa couplings. The contributions → including the Z boson in the Bar-Zee diagram become important in the quark EDM calculation, because there is no accidental suppression like that in the electron EDM calculation. For the CEDM terms, only Barr-Zee diagrams with a top loop contribute. The result at the weak scale

µW mt is then [57, 58] ∼ 3 2√2αs(µW )GF C˜q(µW ) = [f(ztH )Re(cU,i)Im(cq,i) + g(ztH )Re(cq,i)Im(cU,i)] . (44) − (4π)3 i i i X=1 The coefficient of the Weinberg operator at weak scale is [9, 58]

3 √2αs(µW )GF Cg(µW ) = W (ztH )Re(cU,i)Im(cU,i), (45) 4(4π)3 i i X=1 and the loop integration W (z) is listed in section C. To calculate the EDM of the neutron, we must consider the Renormalization Group Equation

(RGE) running effects to evolve these to the hadron scale µH 1 GeV. The one-loop running ∼ gives [58, 104–107]

Cq(µH ) 0.42 0.38 0.07 Cq(µW ) − −       C˜q(µH ) = 0.47 0.15 C˜q(µW ) . (46)        Cg(µH )   0.20   Cg(µW )              There is no quark mass dependence in Cq or C˜q and the evolution of Cg is equivalent to w(µH ) =

0.41w(µW ). According to Equation 38, we only need the quark mass parameters at µH 1 GeV ∼ in the final calculation. The one-loop running mass effect is [2]

mq(1 GeV)/mq(2 GeV) = 1.38 (47) 13 and, with the lattice results at 2 GeV [2, 108, 109], we have

mu(1 GeV) 3.0 MeV, md(1 GeV) 6.5 MeV. (48) ' ' The hadron scale estimation was performed based on QCD sum rules [9, 58, 110–112]7

dn dd(µH ) du(µH ) (22 MeV)w(µH ) + 0.65 0.16 + 0.48d˜d(µH ) + 0.24d˜u(µH ), (49) e ' e − e with an uncertainty of about 50%. The light quark condensation is chosen as qq¯ (1 GeV) = h i (254 MeV)3 [114], which is a bit larger than that from [9, 110]8. Combining all these results − above, we have

dn = m (µH ) 0.27Q C (µW ) + 0.31C˜ (µW ) e d d d d   +mu(µH ) 0.07QuCu(µW ) + 0.16C˜u(µW ) + (9.6 MeV) w(µW ). (50) −  

C. Numerical Analysis for the 2HDMs

In this section we analyze the 2HDM with soft CP-violation, including all the four types of Yukawa interactions. For the electron EDM, the Type I and IV models give the same results, while the Type II and III models give the same results9. In the calculation of electron EDM, Diagrams (a) and (b) in Figure 1 usually contribute dominantly. For Type I and IV models, numerical results show that there is no cancellation among various contributions to the electron EDM, thus the CP-violating phase is strictly constrained. The reason

t,γ/Z,Hi W,γ/Z,Hi is that in these two models, both de and de have the behavior s α /tβ, i i ∝ − 2 2 and thus de cannot go close toP zero when keeping P the CP-violation phases. This behavior is consistent with the results in which only the contribution from H1 is considered [73], because in most cases, the H1 contribution is dominant comparing with the heavy scalars if tβ is not too large, such as . 10.

We take m2,3 500 GeV and m 600 GeV as a benchmark point and find ∼ ± ∼

I,IV 27 s2α2 d 6.7 10− e cm (51) e ' − × t ·  β 

7 The contributions from quark EDM are consistent with a recent lattice calculation with better uncertainty [103], while the lattice calculation on the contributions from quark CEDM and Weinberg operator are still ongoing [113]. 8 Ref. [114] presents the lattice result hqq¯ i(2 GeV) = −(283 MeV)3 and also shows the RGE running effect as 4 dhmqqq¯ i(µ)/d ln µ ∝ mq, which is negligible for u and d quarks. Thus we have hqq¯ i(1 GeV)/hqq¯ i(2 GeV) = mq(2 GeV)/mq(1 GeV) = 0.73. 9 During the calculation of diagram (a) in Figure 1, we consider only top quark in the upper loop and ignore the small contributions from other fermions. Such approximation is good enough when tβ is not too large, for example, . 10. In cases with larger tβ , contributions from bottom quark or τ in the loop will become important. 14

10 in the region tβ 10 and s α 1. This result is not sensitive to α , and gives sα /tβ . 2 2  1 3 | 2 | . 4 4 8.2 10 , which means the CP-phase arg(cf, ) 8.2 10 for f = `i,Ui. This is extremely × − | 1 | . × − small and would not be able to produce interesting CP-violating effects, so in the rest of this work, we do not discuss further on these two 2HDM realizations. For Type II and III models, in contrast, numerical results show significant cancellation behavior for some parameter regions in the electron EDM calculation and thus α is allowed to reach (0.1). 2 O t,γ/Z,Hi The reason is that different terms depend differently on tβ. As shown above, we can divide de

t,γ/Z,Hi t,γ/Z,Hi into two parts as d Re(ct,i)Im(ce,i) and d Re(ce,i)Im(ct,i). Then based on the e,(a) ∝ e,(b) ∝ W,γ/Z,Hi t,γ/Z,Hi t,γ/Z,Hi behavior de + d s α tβ and d s α /tβ, we confirm that i e,(a) ∝ 2 2 i e,(b) ∝ − 2 2 there is alwaysP  some region in which different contributionsP  to electron EDM almost cancel with each other, and thus a large α (0.1) can be allowed. Other contributions may shift mildly | 2| ∼ O the exact location where cancellation happens, but do not modify the cancellation behavior. For these two models, we can discuss two different scenarios: (a) the heavy neutral scalars H2,3 are close in mass and α3 can be changed in a wide range; (b) H2 and H3 have large mass splitting, and thus α3 must be close to 0 or π/2.

FIG. 3: Cancellation behavior between β and α1 in scenario (a) of a Type II and III 2HDM. As an example, the fixed parameters are listed in Table III. The solid lines are the boundaries with d = 1.1 10−29 e cm | e| × · and the regions between solid lines are allowed by the ACME experiment while the dashed lines mean de = 0.

In the left plot, we choose a Type II model. The blue, orange, and red lines are shown for α2 = 0.05, 0.1, 0.15, respectively. In the right plot, we fix α2 = 0.1 and show the comparison between the Type II and Type III models. The orange lines are for the Type II model while the cyan lines are for the Type III model.

Α1 Α1 0.10 0.10

0.05 0.05

Β Β 0.75 0.76 0.77 0.78 0.75 0.76 0.77 0.78

-0.05 -0.05

-0.10 -0.10

10 α2 ' π/2 is not allowed by other experiments, thus we consider only the case α2  1. 15

TABLE III: Fixed parameters of Scenario (a) to discuss the cancellation behavior. With these parameters and β, α1,2, we can calculate m3 through Equation 12, and calculate the couplings through the equations in section A and section B. 2 m1 m2 m± µ α3 125 GeV 500 GeV 600 GeV (450 GeV)2 0.8

We first consider Scenario (a). In this scenario, the cancellation behavior is not sensitive to α3 in a wide region (for example, 0.2 . α3 . 1.4), because the H2,3 are close in mass and thus the dependence on α3 from H2 and H3 contributions almost cancel with each other. Thus, we choose

α3 = 0.8, m2 = 500 GeV and m = 600 GeV as a benchmark point. We focus on the lower tβ ± region, which can generate relative large CP-violation phase in htt¯ vertex11. In the region with

α 0 and tβ 1, we have 1 ∼ ∼

II,III 27 0.904 d 3.4 10− s α tβ e cm, (52) e ' × 2 2 − t ·  β  which means the cancellation appears around tβ 0.95, or equivalently, β 0.76. Different ' ' from the Type I and IV models, a large mixing angle α (0.1) (and hence a CP-phase | 2| ∼ O arg(cf, ) (0.1) for f = `i,Ui) can be allowed due to the cancellation. We show the cancellation | 1 | ∼ O behavior of the electron EDM in the β-α1 plane in Figure 3 for Type II and III models. The electron

EDM sets a strict constraint which behaves as a strong correlation between β and α1. Numerical analysis shows that, with fixed heavy scalar masses, the location where the cancellation happens is not sensitive to α2, which is consistent with the result in Equation 52, but the width of the allowed region is almost proportional to 1/s2α2 . We show this behavior for the Type II model in the left plot of Figure 3, for α2 = 0.05, 0.1, 0.15, using blue, orange and red lines, respectively. The cancellation behavior in the Type III model is similar to that in the Type II model, because the Barr-Zee diagram with a bottom quark loop is negligible and thus the only difference comes from the electron-nucleon interaction part. In the right plot of Figure 3, with fixed α2 = 0.1, we show the comparison results between the Type II model (orange lines) and Type III model

(cyan lines), finding that they are almost the same. When m2,3 increases, the location where the cancellation happens will also change slowly and we show the corresponding results in Figure 4.

When m2 increases from 500 GeV to 900 GeV, the cancellation location also moves slowly from about β 0.76 to β 0.84. The width of the allowed region is almost independent of the heavy ' '

11 −1 As pointed in [67], another cancellation region is around tβ ' (10 − 20). However, arg(ct,1) ∝ tβ thus it is suppressed and difficult to be tested at colliders in this scenario. So we will not discuss the large tβ scenario in this paper. 16

FIG. 4: Mass dependence in the cancellation region in the Type II model. Choosing m± m = 100 GeV, − 2 2 2 α3 = 0.8, α2 = 0.1, α1 = 0, and µ = (450 GeV) as an example, the black line shows the value of β satisfying d = 0 while the dark blue region satisfies d < 1.1 10−29 e cm, which is allowed by the ACME e | e| × · experiment at 90% C.L. If we set α < 0.1, the light blue region is allowed. Results in the Type III model | 1| are almost the same and thus we do not show these. Β

0.85

0.80

0.75

m GeV 600 700 800 900 2 scalar masses, as it is sensitive only to α2. The cancellation behaviorH leadsL to the conclusion that there is always a narrow region which is allowed by the electron EDM measurement, thus we cannot set a definite constraint on the CP-violation mixing angle α2 only through the electron EDM, such as in the ACME experiment. In contrast, the neutron EDM calculation does not involve such a cancellation behavior in the same region as the electron one, thus it can be used to set direct constraints on the CP-violating mixing angle α2. In the parameter region allowed by the electron EDM constraints, the CEDM of the d quark contributes dominantly to the neutron EDM. Numerical analysis shows that the neutron EDM dn s α and it is not sensitive to α , . We calculate its dependence on m in the ∝ 2 2 1 3 2 Type II and III models using the central value estimated in Equation 50 and show the results in the left plot of Figure 5. In the Type II model, α2 is constrained by the neutron EDM (the latest result 26 is dn < 2.2 10 e cm at 95% C.L. [17]). Using the central value estimation in Equation 50, | | × − · α (0.073 0.088) if m changes in the range (500 900) GeV, as shown in the right plot of | 2| . − 2 − Figure 5. Considering the uncertainty in the neutron EDM estimation [110], a larger α 0.15 | 2| ∼ 12 can also be allowed . In the Type III model, there is almost no constraint on α2 from the neutron

12 As discussed above, here we do not consider the region α2 close to π/2 since it corresponds to the case in which H1 is pseudoscalar component dominated, which can be excluded by other experiments. See more details in the 17

FIG. 5: In the left plot, we show the dn/s2α2 dependence on m2 in the Type II (blue) and Type III (orange) models using the central value estimation of Equation 50 in the parameter region allowed by

ACME experiment. We choose α1 = 0 and α3 = 0.8 as an example, but the modification due to these two angles is less than percent level, which is far smaller than the uncertainty in the theoretical estimation

(about 50% level). In the right plot, we show the limit on α2 in the Type II (blue) and III (orange) models. The solid lines are obtained through the estimation of central value and the dashed lines are the boundaries considering the theoretical uncertainty. If theoretical uncertainties are taken into account, we cannot set any limit on α2 in the Type III model through neutron EDM measurements. -26 Α2,max dn s2Α2 10 e×cm 1.00 15 0.50  H L

10 0.20

0.10 5 0.05

m2 GeV m GeV 600 700 800 900 600 700 800 900 2

13 EDM . That’s because in Type III model, Re(H cu,iL)Im(cd,i) = Re(cd,i)Im(cu,i), whichH is differentL − from the relation in Type II model. It leads to an accidental partial cancellation between the two terms (see Equation 44) in the d quark CEDM contribution, which dominates the neutron EDM calculation.

Next, we discuss Scenario (b), in which a large mass splitting exists in m2,3, corresponding to the cases in which α3 is close to either π/2 or 0. From Equation 12, we can find two solutions for tα3 as

m2 m2 m2 m2 2 s2 4 m2 m2 m2 m2 s2 c2 3 − 2 ± 3 − 2 2β+α1 − 3 − 1 2 − 1 α2 2β+α1 tα± = . (53) 3 q 2 2  2m m sα2 c2β+α1   2 − 1 +  + In the large mass splitting scenario, α3 is close to π/2, and α3− is close to 0. In the α3 case, H2 is a CP-mixed state in which the pseudoscalar component is dominant, while H3 is almost a pure scalar. Conversely, in the α3− case, H3 is a CP-mixed state while H2 is almost a pure scalar. In this scenario, the large mass splitting between H , leads to a significant H H Z decay, because 2 3 3 → 2

next section. 13 If we consider only the central value of the neutron EDM estimation Equation 50, the constraint is about |s2α2 | . 0.9, meaning that α2,max is already close to π/4. However, if the large theoretical uncertainty in the neutron EDM

estimation is also taken into account, we cannot exclude any value for |s2α2 | ≤ 1, which means no constraint on |α2| can be set in the Type III model. 18

the coupling is just cV,1, which is not suppressed by mixing angles. Numerical analysis shows a similar cancellation behavior as Scenario (a) in both α3± cases. We show the results of the Type II model in the upper two plots in Figure 6. Similar to Scenario (a), the cancellation behavior in the Type III model is almost the same as that in the Type II model and we show the comparison in the lower two plots in Figure 6.

FIG. 6: Similar to Scenario (a), the electron EDM sets a strict constraint which behaves as a strong correlation between β and α1. As an example, the fixed parameters are listed in Table IV. We show the cancellation behavior of the Type II model in the upper two plots and present the comparison between the Type II and III models in the lower two plots. The color notation is the same as that in Figure 3. The left + − two plots correspond to the case α3 , while the right two plots correspond to the case α3 . We approximately have α+ π/2 1.5 10−2α and α− 0.52α . 3 ' − × 2 3 ' − 2 Α1 Α1 0.10 0.10

0.05 0.05

Β Β 0.76 0.77 0.78 0.79 0.87 0.88 0.89 0.90

-0.05 -0.05

-0.10 -0.10 Α1 Α1 0.10 0.10

0.05 0.05

Β Β 0.76 0.77 0.78 0.79 0.87 0.88 0.89 0.90

-0.05 -0.05

-0.10 -0.10

The behavior of the neutron EDM is also similar to that of Scenario (a). In the regions allowed by electron EDM constraint, dn is only sensitive to α2 and is almost independent of α1. With the benchmark points in Table IV, and using the indices II/III and +/ to denote Type II/III models − 19

TABLE IV: Fixed parameters of Scenario (b) to discuss the cancellation behavior. With these parameters ± and β, α1,2, we can calculate α3 through Equation 53, and calculate the couplings through the equations in section A and section B. 2 m1 m2 m3 m± µ 125 GeV 500 GeV 650 GeV 700 GeV (450 GeV)2

+/ and α − cases, we have

II,+ 25 d /s α 1.4 10− e cm, (54) n 2 2 ' × · II, 25 d −/s α 1.3 10− e cm, (55) n 2 2 ' × · III,+ 26 d /s α 2.4 10− e cm, (56) n 2 2 ' × · III, 26 d −/s α 1.9 10− e cm, (57) n 2 2 ' × · based on the central value estimation in Equation 50. Thus, we can obtain the upper limit on α2 in the Type II model as

+ 0.079, (α3 case), α2 . (58)  0.085, (α case).  3−

There is no constraint on α2 from the neutron EDM in the Type III model, due to the same reason as discussed above for Scenario (a).

In both Scenarios (a) and (b), the cancellation can appear around the region tβ 1, thus both ' α and arg(ct, ) can reach (0.1), which lead us to the phenomenological studies of CP-violation 2 1 O in ttH¯ 1 production in section V. For this process, both scenarios have similar behaviors. In the future, if we go deeper into the phenomenology of heavy scalars, differences between these two scenarios will arise. For example, there will be H ZH decay in Scenario (b), but such process 3 → 2 cannot appear in Scenario (a).

D. Future Neutron EDM Tests

Several groups are currently planning new measurements on neutron EDM, to the accuracy of (10 27 e cm) or even better [10, 13, 115–119]. Such an order of magnitude improvement in O − · accuracy would be very helpful to perform further tests on the 2HDM Type II and III scenarios considered here.

If no anomaly is discovered in future neutron EDM measurements, the upper limit on dn would improve to about 10 27 e cm, and there would be more stringent limits on α in both Type II and − · 2 20

FIG. 7: Upper limit on α in the Type II and III models when the future limit decreases to d < 10−27 e cm. 2 | n| · The color scheme is the same as above: blue for the Type II model and orange for the Type III model. The solid lines are obtained using the central value estimation and, if we consider the current theoretical uncertainty estimation of [110], the boundaries of the limits on α2 are the dashed lines. Α2,max 0.100 0.050

0.020 0.010 0.005

0.002 m GeV 600 700 800 900 2

III models, as shown in Figure 7 for Scenario (a). With future neutronH EDML measurements, α2 can be constrained to (10 2) in the Type III model and to (10 3) in Type II model. Similar O − O − constraints can be placed in Scenario (b). In current analysis, the expected limit on α2 still contain large uncertainties (see the colored bands in Figure 7), due to the theoretical uncertainties in the estimation of neutron EDM from sum rules [110]. Future theoretical estimation on neutron EDM from lattice is expected to have better accuracy, for example, (10%) at lattice [103, 113], thus ∼ O 14 it will be more effective to obtain the future limit on α2 with smaller uncertainties . In contrast, if α (0.1), there will be significant BSM evidence in future neutron EDM 2 ∼ O measurements. In the models which contain a similar cancellation mechanism in electron EDM, the neutron EDM experiments may be used to find the first evidence of new CP-violation source or set the strictest limit directly on the CP-violating phase α2.

14 To obtain an effective limit, the uncertainty must be not too large, for example, similar to or even larger than the central value. As a comparison, the EDMs for diamagnetic atoms are also good candidates to probe new CP-violation [120–122]. However, based on the results in [56, 67, 102, 123], we have the EDM for 199Hg atom as II +2.3 −27 III +1.9 −27 dHg/s2α2 ' (−1.7−2.5)×10 e·cm and dHg/s2α2 ' (−1.3−0.8)×10 e·cm, for Scenario (a) with m2 = 500 GeV in Type II and III models respectively. The results cross zero within 1σ level due to large theoretical uncertainties, 199 meaning that it is impossible to set constraints directly on α2 through the EDM of Hg (or similar atoms) in the low tβ region. 21

E. Summary on EDM Tests

In the previous subsections, we have discussed the electron and neutron EDM tests in the 2HDM with soft CP-violation. There is no cancellation mechanism in the Type I and IV models and thus the electron EDM can set strict constraints on the CP-violation angle as arg(cf, ) sα /tβ | 1 | ' | 2 | . 8.2 10 4. However, this value is too small to give any observable CP effects in other experiments, × − thus we decided not to have further discussions on these two 2HDM realizations. In contrast, cancellations among various contributions to the electron EDM can occur in the Type II and III models. Here, we still face stringent constraints but these will induce a strong correlation between

β and α1. We cannot set constraints directly on the CP-violation mixing angle α2 though. The behavior is the same in the Type II and III models. In fact, it is also the same in both Scenario

(a), in which m2,3 are close to each other, and in Scenario (b), in which m2,3 have large splitting.

A cancellation generally happens around tβ 1 with the exact location depending weakly on the ∼ masses of the heavy (pseudo)scalars. Current measurements of the neutron EDM can set an upper limit on α (0.073 0.088) in | 2| ' − the Type II model, depending on different scenarios and masses, if we take the central value of the neutron EDM estimation. Such limits can be weakened to about 0.15 if we consider the theoretical uncertainty. But one cannot set limits on α2 in the Type III model, because the CEDM of the d quark in this model is suppressed by a partial cancellation. However, α2 in the Type III model is constrained by collider tests, which will be discussed in the next section. Finally, we showed the importance of future neutron EDM measurements in our models relying on the cancellation mechanism in the electron EDM. For α (0.1), there would be 2 ∼ O significant evidence in future neutron EDM experiments, which will be more sensitive than any other experiments. And if there is no evidence of non-zero neutron EDM, the improved limit on the neutron EDM will set strict constraints on the CP-violation mixing angle: the upper limit of α will reach (10 2) in the Type III model and (10 3) in the Type II model. To explain the | 2| O − O − 2 matter-antimatter asymmetry, arg(ct, ) 10 is required [74–77]. Thus if future neutron EDM | 1 | & − experiments still show null results to the accuracy 10 27 e cm, the Type II model will not be ∼ − · able to explain the matter-antimatter asymmetry, due to the very strict constraint on α2. 22

IV. CURRENT COLLIDER CONSTRAINTS

Any BSM model must face LHC tests. In our 2HDM with soft CP-violation, as mentioned, we treat H1 as the 125 GeV Higgs boson. In this scenario then, the latter mixes with the other (pseudo)scalar states and its couplings will be modified from the corresponding SM values. However, these modified couplings are constrained by global fits on the so-called Higgs signal- strength measurements. In addition, the scalar sector is extended in a 2HDM, so that direct searches for these new particles at the LHC will also set further constraints on this BSM scenario. In this respect, we discuss only the 2HDM Type II and III, in which the cancellation behavior in the electron EDM still allow a large CP-phase in Yukawa interactions.

A. Global Fit on Higgs Signal Strengths

The Higgs boson H1 can be mainly produced at the LHC through four channels: gluon fusion

(ggF), vector boson fusion (VBF), associated production with vector boson (V +H1, here V = W, Z) or a top quark pair (tt¯+ H ) [124–127]. The decay channels H b¯b, τ +τ , γγ, W W and ZZ 1 → − ∗ ∗ have already been discovered. Define the signal strength µi,f corresponding to production channel i and decay channel f as follows:

σi Γf Γtot,SM µi,f , (59) ≡ σi,SM · Γf,SM · Γtot where σi denotes the production cross section of the production channel i amongst those listed above, Γf denotes the decay width of channel f and Γtot denotes the total decay width of H1. A quantity with index “SM” denotes the value predicted by the SM. Such signal streengths for different channels have been measured by the ATLAS [128–131] and CMS [132–134] collaborations: we list them in Table V.

As intimated, in the 2HDM, H1 couplings to SM particles are modified due to the mixing with other (pseudo)scalars and thus the aforementioned signal strengths are modified. The production cross sections satisfy [135–137]

σVBF σV +H 2 = = cV,1, (60) σVBF,SM σV +H,SM z 2 H1t σggF 1 4 2 2 = Re(ct,1) + i B z Im(ct,1) [Re(ct,1)] + 2.3 [Im(ct,1)] , (61) H1t σggF,SM 1 ' A 4  σtt¯+H 2 2 [Re(ct,1)] + 0.37 [Im(ct,1)] , (62) σtt¯+H,SM ' 23

TABLE V: Signal strengths measurements by the ATLAS (left) and CMS (right) collaborations at √s = 13 TeV. The luminosity is 139 fb−1 for the ATLAS measurements and 137 fb−1 for the ≤ ≤ CMS measurements.

ggF VBF V + H tt¯+ H ggF VBF V + H tt¯+ H H b¯b - 3.01+1.67 1.19+0.27 0.79+0.60 H b¯b 2.45+2.53 - 1.06+0.26 1.13+0.33 → −1.61 −0.25 −0.59 → −2.35 −0.25 −0.30 H τ +τ − 0.96+0.59 1.16+0.58 - 1.38+1.13 H τ +τ − 0.39+0.38 1.05+0.30 2.2+1.1 0.81+0.74 → −0.52 −0.53 −0.96 → −0.39 −0.29 −1.0 −0.67 H γγ 0.96+0.14 1.39+0.40 1.09+0.58 1.38+0.32 H γγ 1.09+0.15 0.77+0.37 - 1.62+0.52 → −0.14 −0.35 −0.54 −0.30 → −0.14 −0.29 −0.43 H WW ∗ 1.08+0.19 0.59+0.36 - 1.56+0.42 H WW ∗ 1.28+0.20 0.63+0.65 1.64+1.36 0.93+0.48 → −0.19 −0.35 −0.40 → −0.19 −0.61 −1.14 −0.45 H ZZ∗ 1.04+0.16 2.68+0.98 0.68+1.20 - H ZZ∗ 0.98+0.12 0.57+0.46 1.10+0.96 0.25+1.03 → −0.15 −0.83 −0.78 → −0.11 −0.36 −0.74 −0.25 while the decay widths satisfy [135, 136]

ΓZZ∗ ΓWW ∗ 2 = = cV,1, (63) ΓZZ∗,SM ΓWW ∗,SM

Γff¯ 2 = cf,1 , (f = c, b, τ), (64) Γff,¯ SM | | z 2 H1t Γgg 1 4 2 2 = Re(ct,1) + i B z Im(ct,1) [Re(ct,1)] + 2.3 [Im(ct,1)] , (65) H1t Γgg,SM 1 ' A 4  c v2 z z z z 2 ±,1 1,±  H1W 4 H1t H1t m2 0( 4 ) + cV,1 2( 4 ) + 3 Re(ct,1) 1( 4 ) + iIm(ct,1) 1( 4 ) Γγγ 2 ± A A A B = 4 zH t zH W Γγγ,SM ( 1 ) + ( 1 )  3 1 4 2 4 A A 2 2 [1.28cV,1 0.28Re(ct,1) 0.02] + 0.19 [Im(ct,1)] . (66) ' − −

The loop functions , , and are listed in section D. Here, cV, = cα cα holds for all types of A0 1 2 B1 1 1 2 models, while cf,1 which depends on the model type are listed in section A. The tt¯+H1 cross section ratio in Equation 62 is only valid for the LHC at √s = 13 TeV. For the γγ decay Equation 66, the charged Higgs loop contribution is small compared with the top quark and W loops, and we choose the case m = 600 GeV for illustration. The total width satisfies ± Γtot SM Γf = BRf . (67) Γ · Γf, tot,SM f SM X SM BRf is the SM prediction on the Branching Ratio (BR) of the SM Higgs boson decay to the final state f, thus all the modifications are normalized to the SM values. For the 125 GeV SM Higgs boson, we list the theoretical predictions on the BRs of the main decay channels in Table VI [127].

We perform χ2-fits where

exp th 2 µi,f µi,f χ2 − , (68) ≡ δµ2 i,f i,f ! X 24

TABLE VI: Predictions of the main BRs of the SM Higgs boson with mass 125 GeV.

SM SM SM SM SM SM BR BR + BR BR BR BR b¯b τ τ − cc¯ WW ∗ ZZ∗ gg 58.2% 6.3% 2.9% 21.4% 2.6% 8.2%

th exp where µi,f is the theoretically predicted signal strength, µi,f is the experimentally measured one and δµi,f is the associated uncertainty. The possible small correlations across production and decay 2 channels are ignored. For a 2HDM, χ depends only on β, α1,2. We perform global fits for the Type II and III models, in which α (0.1) is still allowed. The minimal χ2 (denoted by χ2 ) 2 ∼ O min obtained from ATLAS and CMS data as well as the combined one are listed in Table VII. The

2 TABLE VII: The χmin/d.o.f. for the Type II and Type III models using ATLAS data, CMS data and their combination, respectively.

2 χmin/d.o.f. ATLAS CMS ATLAS+CMS Type II 11.8/13 12.2/15 24.2/31 Type III 12.7/13 11.9/15 24.8/31

fitting, normalized to the degrees of freedom (d.o.f.), is good enough because the models approach 2 2 2 the SM limit when α , 0. If one then defines δχ χ χ , this is useful to find the allowed 1 2 → ≡ − min parameter regions of the two 2HDM realizations considered. Our numerical study shows that the results depend weakly on β. We choose β = 0.76 (corresponding to m , 500 GeV in Scenario 2 3 ∼ (a)) as an example and show the allowed region from combined ATLAS and CMS results in the α α plane in Figure 8. For both Type II and III, the global fit requires α 0.33 in the 2 − 1 | 2| . region β (0.7 1). Forthe Type II model, this constraint is weaker when compared with that ∼ − from the neutron EDM. Nevertheless, it can set a new constraint on α for the Type III model. | 2| The allowed range for α in the latter is wider than the one in the Type II model, in fact. In both | 1| models, α1 is favored when close to 0, thus, in the following discussion, we usually fix α1 = 0.02, a value which is not far from the best fit points in most cases. In Figure 9, we show instead the allowed regions in the α β plane for fixed α = 0.1, 0.2 in the Type III model. The dependence 1 − 2 on β is indeed weak, but it increases somewhat when α2 gets larger, as shown in the figure. 25

FIG. 8: Allowed regions in the α α plane obtained by using the combined results from the ATLAS and 2 − 1 CMS collaborations, with fixed β = 0.76 for Type II (left) and Type III (right). Green regions are allowed at 68% C.L. (δχ2 2.3) and yellow regions are allowed at 95% C.L. (δχ2 6.0). ≤ ≤ Α2 Α2 0.4 0.4

0.2 0.2

Α1 Α -0.04 -0.02 0.02 0.04 0.06 0.08 0.10 -0.10 -0.05 0.05 0.10 0.15 0.20 1

-0.2 -0.2

-0.4 -0.4

FIG. 9: Allowed regions in the α β plane obtained by using the combined results from the ATLAS and 1 − CMS collaborations, with fixed α2 = 0.1 (left) and 0.2 (right), in the Type III model. Green regions are allowed at 68% C.L. (δχ2 2.3) and yellow regions are allowed at 95% C.L. (δχ2 6.0). ≤ ≤ Α1 Α1 0.20 0.20

0.15 0.15

0.10 0.10

0.05 0.05

Β Β 0.75 0.80 0.85 0.90 0.95 1.00 0.75 0.80 0.85 0.90 0.95 1.00

-0.05 -0.05

-0.10 -0.10

B. LHC Direct Searches for Heavy Scalars: through ZZ Final State

In the 2HDM, there are four additional scalars, H2,3 and H±, beyond the SM-like one H1. Thus, we must also check the direct searches for these (pseudo)scalars at the LHC. Notice that H2,3 decay to tt¯ dominantly and we show their decay widths and BRs in section E. The H , 2H decays 2 3 → 1 are ignored because such channels are suppressed in the allowed parameter region isolated so far.

In Scenario (b), H ZH decay is also open if m m > mZ . In addition, H decays to tb¯ 3 → 2 3 − 2 − 26 dominantly.

In this section we discuss the process gg H , ZZ. Theoretically, this process is sensitive → 2 3 → to the couplings between H2,3 and the gauge vector bosons, hence sensitive to α2. Experimentally, this process is the most sensitive channel in searching for heavy neutral scalars. The current LHC limit for m2 = 500 GeV is σgg H2,3 ZZ . 0.1 pb at 95% C.L. [138] at √s = 13 TeV with about 40 → → 1 fb of luminosity. We first consider the resonance cross section of gg H , ZZ process. For − → 2 3 → Scenario (a), in which H , are close in mass such that m m (GeV) Γ , 20 GeV for 2 3 | 2 − 3| ' O  2 3 ' m 500 GeV (where we have denoted by Γ , the widths of the two heavy Higgs states), we must 2 ' 2 3 consider the interference between the H2 and H3 production processes. To the one-loop order, we have for the resonance cross section

res σZZ = σS + σP , (69) where σS is the contribution from Re(ct,2,3) corresponding to the CP-conserving part, and σP is the contribution from Im(ct,2,3) corresponding to the CP-violation part. Their ZZ invariant mass distributions are then separately given by

2 dσS q = dx dx fg(x )fg(x )δ x x σˆS(q) dq 1 2 1 2 1 2 − s Z   2 3 2q m2Γ0(q) cV,iRe(ct,i) 2 2 , (70) × πs q m imiΓi i=2,3 i X − − 2 dσP q = dx dx fg(x )fg(x )δ x x σˆP (q) dq 1 2 1 2 1 2 − s Z   2 3 2q m2Γ0(q) cV,iIm(ct,i) 2 2 . (71) × πs q m imiΓi i=2,3 i X − −

In the equations above, fg(x) denotes the gluon Parton Distribution Function (PDF), which, in our numerical study, is chosen to be the MSTW2008 set [139]. The function [135, 136]

q3 4m2 4m2 12m4 Γ (q) = 1 Z 1 Z + Z , (72) 0 32πv2 − q2 − q2 q4     is the decay width to the ZZ final state of a would-be SM Higgs boson with mass q. The functions [135, 136]

2 2 2 GF αs 3 q σˆS(q) = 1 , (73) 288√2π 4A 4m2  t  2 2 2 GF αs 3 q σˆP (q) = 1 , (74) 288√2π 4B 4m2  t 

27

are the parton-level cross sections of a pure scalar(pseudoscalar) state with couplings ct = 1(i). The loop functions and are listed in section D. A1 B1 The SM gg ZZ production arise through the box diagrams, which leads to the interference → int effects with the resonance production. We denote σZZ as the cross section induced by interference between resonance and SM background. To one-loop level, our numerical calculation show that if α (0.1), we have σint /σres (10 3) [140–143], meaning that we can safely ignore the | 2| ∼ O | ZZ ZZ | ∼ O − interference effects and consider only the resonance production15. Thus, the total cross section (without SM background) is approximately the resonance cross section

m2,3 ∆q/2 − dσ dσ σtot σres = dq S + P . (75) ZZ ≈ ZZ dq dq m2,3Z ∆q/2   − For m 500 GeV, we choose ∆q = 50 GeV as the mass window where interference between H , 2 ' 2 3 is accounted for. Numerically, we show the cross sections depending on the mixing angles in Figure 10 by fixing m2 = 500 GeV in the Type III model. The left plot is for Scenario (a) and the right plot is

FIG. 10: Cross sections σtot σres as a function of the mixing angles α in the Type III model. In the ZZ ≈ ZZ 2,3 left plot, we show the cross section depending on α3 in Scenario (a), fixing β = 0.76 and α1 = 0.02. From top to bottom, the four lines show results with α2 = 0.33, 0.27, 0.2, 0.14, respectively. In the right plot, we show the cross section depending on α2 in Scenario (b), fixing β = 0.76 and α1 = 0.02, with α3 chosen as α+( 1.5 10−2α ) which corresponds to m 650 GeV. 3 ' × 2 3 ' Σ pb Σ pb

0.12 0.15H L H L 0.10

0.08 0.10 0.06

0.05 0.04

0.02

Α Α 0.4 0.6 0.8 1.0 1.2 3 0.20 0.25 0.30 2

15 Different from the tt¯ production below, here the interference effects in ZZ production is very small comparing with the resonance production. The reasons are: (i) the SM amplitude generated through box diagrams contains a loop suppression; (ii) the interference only happens between the SM and the CP-conserving part of resonance 2 2 amplitude AS ∝ sα2 in both scenarios (σS ∝ |AS | ). While for the CP-violation part, the amplitude AP ∝ sα2 cα2 , 2 tot res thus σP ∝ |AP | contributes dominantly to the total cross section σZZ ≈ σZZ . 28

+ for Scenario (b) for the α3 case. In both scenarios, we can see that α2 . 0.27 is favored when m2 = 500 GeV. For Scenario (a), when we choose α2 = 0.27, α3 . 0.4 or & 1.2 is favored, which still keeps H2,3 nearly degenerate in mass. While in the cases α2 . 0.2 or m2 & 600 GeV, there is no further constraints on α3. For Scenario (b), α3 is fixed by other parameters. In the α3− case, c2,V is suppressed (close to α1), thus it faces no further constraints here. In the Type II model, we can obtain the same cross section as that in the Type III model with the same parameters. In the Type II model, due to the stricter neutron EDM constraint on α2, the considered parameter space is always allowed by the collider data. Thus, in the following phenomenological analysis, we generally choose α2 = 0.27 (unless stated otherwise) as a benchmark point, corresponding to the largest allowed CP-violation effects in Type III model with m2 = 500 GeV.

C. LHC Direct Searches for Heavy Scalars: through tt¯ and other Final States

As mentioned, H2,3 decay dominantly to a tt¯ final state and the current LHC limit for m2 = 1 500 GeV is about σpp H2,3 tt¯ . 7 pb at 95% C.L. [144] at √s = 13 TeV and 36 fb− of luminosity. → → In contrast to the ZZ channel, the interference with SM background is very important in the tt¯ channel [145, 146], which strongly decreases the signal cross section compared with the pure resonance production cross section, so long that non-resonant Higgs diagrams can be subtracted [147]. The total cross section can be divided into

σgg tt¯ = σSM + σres + σint = σSM + δσtt¯. (76) →

Here, σ denotes the SM background cross section of gg tt¯ process; while σ and σ denote SM → res int the resonant and interference cross section, separately. Furthermore, δσtt¯ is the cross section difference between 2HDM and SM, i.e.,

δσ ¯ σ + σ = dx dx fg(x )fg(x ) (ˆσ +σ ˆ ) , (77) tt ≡ res int 1 2 1 2 res int Z 29 whereσ ˆ denotes the parton-level cross section as a function of the tt¯ invariant mass q. Following the results in [145, 146], we have

σˆres =σ ˆres,S +σ ˆres,P 2 2 2 q2 q2 2 2 2 4 [Re(ct,i)] 1 2 [Re(ct,i)Im(ct,i)] 1 2 3αsGF mt q 3 A 4mt B 4mt = 3 βt 2 2 + 2 2 4096π   q m imiΓi  q m imiΓi   i=2,3 − i − i=2,3 − i −   X X  2 2   q2 2 q2  [Re(ct,i )Im(ct,i)] 1 2 [Im( ct,i)] 1 2 A 4mt B 4mt + βt 2 2 + 2 2 , (78)  q m imiΓi  q m imiΓi  i=2,3 i i=2,3 i X − − X − −   σˆint =σ ˆint,S+ σ ˆint,P 

1 2 αsG m = dc F t θ 2 2 − 64√2π(1 βt cθ) Z1 − − 2 q2 2 q2 [Re(ct,i)] 1 2 [Im(ct,i)] 1 2 3 A 4mt B 4mt Re β + βt . (79) ×  t q2 m2 im Γ  q2 m2 im Γ  i , i i i i , i i i X=2 3 − − X=2 3 − −   2 2 2 Here, q = x x s, βt = 1 4m /q is the velocity of the top quark in the tt¯ center-of-mass 1 2 − t frame. In our numerical study,p we set q in the range m ∆ q/2 < q < m + ∆ q/2, where we 2 − 0 2 0 choose the mass window ∆0q = 100 GeV for m2 = 500 GeV. We choose the MSTW2008 PDF [139] as above. We show the cross sections for some benchmark points in both Scenario (a) and Scenario (b) in Table VIII. The numerical results show that, for all benchmark points we consider,

TABLE VIII: Cross sections δσtt¯ at the LHC with √s = 13 TeV, fixing m2 = 500 GeV and α1 = 0.02. II Further, for the Type II model (denoted as δσtt¯) we fix α2 = 0.14 while for the Type III model (denoted as III δσtt¯ ) we fix α2 = 0.27. The left table is for Scenario (a), in which we fix β = 0.76 and choose α3 = 0.4, 0.8, 1.2 from top to bottom. The right table is for Scenario (b), in which we fix m3 = 650 GeV, considering two + − cases: β = 0.77, α3 = α3 and β = 0.885, α3 = α3 , again, from top to bottom.

II III α3 δσ ¯ (pb) δσ ¯ (pb) tt tt II III α3 δσtt¯ (pb) δσtt¯ (pb) 0.4 0.04 0.40 − + α3 0.43 0.67 0.8 0.39 0.11 − − − − α3 0.72 0.53 1.2 0.25 0.07 −

the interference with the SM background significantly breaks the resonance structure of H2,3 and decreases the cross sections to around (even below) 0, which means the tt¯ resonant search at the 30

LHC cannot set limits on this model16.

The H2,3 states can also be produced in association with a tt¯ pair at the LHC, thus we should also check this constraint for our favored benchmark points. Since H2,3 mainly decay into a tt¯pair, the whole production and decay process will modify the cross section of the pp ttt¯ t¯process (which → we denote by σ4t), which current LHC limit is about 22.5 fb at 95% C.L. [150] at √s = 13 TeV 1 17 with 137 fb− of integrated luminosity by CMS collaboration . The interference effects between SM and BSM contributions are expected to be significant [152]. We estimate this cross section in the 2HDM considering all interference effects by using Madgraph5 aMC@NLO [153, 154]. We then show the numerical results in Table IX for some benchmark points, all allowed by current LHC limits.

TABLE IX: Cross sections σ4t at the LHC with √s = 13 TeV, fixing m2 = 500 GeV and α1 = 0.02. Further, II III for the Type II model (denoted as σ4t) we fix α2 = 0.14 while for the Type III model (denoted as σ4t ) we

fix α2 = 0.27. The left table is for Scenario (a), in which we fix β = 0.76 and choose α3 = 0.4, 0.8, 1.2 from top to bottom. The right table is for Scenario (b), in which we fix m3 = 650 GeV, considering two cases: + − β = 0.77, α3 = α3 and β = 0.885, α3 = α3 , again, from top to bottom.

II III α3 σ (fb) σ (fb) 4t 4t II III α3 σ4t (fb) σ4t (fb) 0.4 19.9 17.9 + α3 15.9 14.3 0.8 20.8 18.7 − α3 10.4 9.4 1.2 20.8 19.3

Finally, we should also check the direct LHC limits on the charged Higgs boson H±. As mentioned above, b sγ decay favors a heavy H± state with mass m & 600 GeV [81, 84]. For → ± m = 600 GeV, the current LHC limit is about 0.1 pb at 95% C.L. [155, 156] at √s = 13 with ± 1 some 36 fb− of luminosity TeV. For large tβ, the interference effect is negligible [157]. However, in the Type II and Type III models with CP-violation as considered above, tβ 1 is favored. For ∼ m 600 GeV, its width Γ & 30 GeV, which leads to significant interference effects. Again, ± ' ± we estimate the cross section considering all interference effects using Madgraph5 aMC@NLO [153, 154]. If we denote by δσ the cross section modification (including both the resonant and ±

16 In some experimental analysis [148, 149], the interference effects between (pseudo)scalar resonance and the SM background were taken into account. Yet, the results cannot be simply rescaled to our CP-violating scenario, because the existence of CP-violation will modify the shape of the tt¯ invariant mass compared with the CP- conserving case. We still need further studies on such scenarios. 17 +7 √ −1 Recently ATLAS collaboration also presented their measurement σ4t = 24−6 fb at s = 13 TeV with 137 fb of integrated luminosity [151]. It is consistent with the CMS result and SM prediction within 2σ level, but the constraint is a bit weaker as σ4t . 38 fb at 95% C.L. 31 interference effects) to SM ttb¯ ¯b process, our numerical estimation show that

δσ = 0.38 pb < 0 (80) ± − for m = 600 GeV and β = 0.76. That means that the interference effect significantly decreases ± the H± production cross section in this parameter region, thus the latter is not constrained by current LHC experiments.

D. Summary on Collider Constraints

The 125 GeV Higgs (H ) signal strength measurements lead to a constraint α 0.33, which 1 | 2| . depends weakly on β. The LHC direct searches for heavy neutral scalars decaying to the ZZ final state set a stricter constraint α 0.27 for m = 500 GeV in both Scenario (a) and (b). When | 2| . 2 m (550 600) GeV, the constraint from direct searches becomes weaker than that from the 2 & − global fit ton the H1 signal strengths. In further analysis, we prefer to choose α2 = 0.27, which is 18 the largest allowed value for m2 = 500 GeV . We have also checked the constraints from tt¯, ttt¯ t¯and charged Higgs boson searches, in which the interference effects are very important. All benchmark points that we have considered are allowed by current LHC measurements. In the remainder of this work, we focus on the phenomenology of CP-violation in ttH¯ 1 associate production. We will instead consider the production and decay phenomenology of the heavy (pseudo)scalars H2,3 in a forthcoming paper.

V. LHC PHENOMENOLOGY OF CP-VIOLATION IN ttH¯ 1 PRODUCTION

In this section, we study the production of the lightest neutral Higgs boson H1 in association with a tt¯pair at the LHC. We start by discussing the phenomenological set-up used in our analysis, discuss the observables which can be used to probe of the CP -nature of the ttH¯ 1 coupling, both inclusive and differential; and close the section by demonstrating the sensitivity results for a selected benchmark point for the final state consisting of two charged leptons, n 4 jets and missing ≥ miss transverse energy ET which is associated with neutrinos from W -decays.

18 + − Recently CMS collaboration presented the latest direct constraint on CP-violation in τ τ H1 interaction [158]. They obtain the CP-phase | arg(cτ,1)| . 0.6 at 95% C.L., corresponding to |α2| . 0.6 in 2HDM Type II or III with tβ ' 1. This is much weaker than our indirect constraint. 32

A. Phenomenological Set-up

Events are generated at Leading Order (LO) using the Madgraph5 aMC@NLO [153, 154]. Cross sections of signal processes are calculated using a UFO model file [159] corresponding to a Type II 2HDM19 with flavor-conservation [160] slightly modified to account for CP-violation effects in vertices involving both the neutral (Hi, with i = 1, 2, 3) and charged (H±) Higgs boson states. Here, we employ the LO version of the Mmhtlo68cl PDF sets [161]. For both the signal and background processes, we have used the nominal value for the (identical) renormalization and factorization scales to be equal to half the scalar sum of the transverse mass of all final state particles on an event-by-event basis, i.e.:

N 1 2 2 µR = µF = m + p . (81) 2 i T,i i X=1 q In the computation of the parton level cross sections, we have employed the Gµ-scheme, where the input parameters are GF , αem and mZ , the numerical values of which are given by

5 2 1 GF = 1.16639 10− GeV− , α− (0) = 137, and mZ = 91.188 GeV. (82) × em

2 The values for mW and sin θW are computed from the above inputs. For the pole masses of the fermions, we have taken

mt = 172.5 GeV, mb = 4.7 GeV. (83)

Uncertainties due to the scale and PDF variations are computed using SysCalc[162]. In order to keep full spin correlations at both the production and decay stages of the top quarks, we have employed MadSpin [163]. Pythia8 [164] is used to perform parton showering and hadronization, albeit without including Multiple Parton Interactions (MPIs), to the events, eventually producing a set of event files in HepMC format [165]. The HepMC files are passed to Rivet (version 2.7.1)

[166] for a particle level analysis. In the latter, jets are clustered using the anti-kT algorithm using FastJets [167, 168]20. The particle level events are selected if they contain two charged leptons, high jet multiplicity of 4-6 jets, where at least four of them are b-tagged, and missing transverse energy which corresponds to the SM neutrino from the decays of W -gauge bosons. Only prompt electrons and muons directly

19 It can also be use for Type III 2HDM. 20 Results were found to be stable if replacing Pythia8 with Herwig6.5 [169–172] and the anti-kT algorithm with the Cambridge-Aachen one [173, 174]. 33 connected to the W boson are accepted, i.e., we do not select those coming from τ decays. Electrons are selected if they pass the basic selection requirement of pe > 30 GeV and ηe < 2.5 (excluding T | | the ones that fall in the end-cap or transition regions of the calorimeter, i.e. with 1.37 < ηe < 1.52) | | while muons are selected if they satisfy the conditions pµ > 27 GeV and ηµ < 2.4. Jets are T | | clustered with jet radius D = 0.4 and selected if they satisfy pj > 30 GeV and ηj < 2.4. For T | | b-tagging, we use the so-called ghost-association technique [175, 176]. In this method, a jet is b- i tagged if all the jet particles i within ∆R(jet, i) < 0.3 of a given anti-kT jet satisfy pT > 5 GeV. We assume a b-tagging efficiency of 80% independent of the transverse momentum of the jet. For top quark reconstruction, we use the PseudoTop definition [177] (more details along with validation plots can be found in section F). Finally, we require that the invariant mass of b¯b system forming the H candidate is around the H mass, m ¯ m < 15 GeV, and the transverse energy of the 1 1 | bb − 1| b¯b system forming the H1 candidate is larger than 50 GeV.

B. Inclusive ttH¯ 1 Cross Section

The parton level Feynman for ttH¯ 1 production at Leading-Order (LO) are depicted in Figure 11. The cross section has two contributions: (i) from qq¯ annihilation,diagram (a) in Figure 11, which is expected to dominate in the region of medium and large x =p ˜i/P withp ˜i and P are the longitudinal momenta of the parton i and the proton respectively; and (ii) from gg fusion (ggF), diagrams (b) and (c) in Figure 11, dominating at low x. For the calculation of the cross section, we employ Madgraph5 amc@nlo [153, 154] with the Mmhtlo68cl and Mmhtnlo68cl PDF sets [161] in the 4-flavor scheme. Systematic uncertainties are divided into two categories: scale and PDF ones. The scale uncertainties are obtained by varying the renormalization and factorization scales by a factor of two around their nominal value, i.e.,

0 0 (µR, µF ) = (1, 1), (1, 0.5), (1, 2), (0.5, 1), (0.5, 0.5), (0.5, 2), (2, 1), (2, 0.5), (2, 2) (µ , µ ), (84) { } R F with

1 µ0 = µ0 = p2 + m2. (85) F R 2 T,i i i X q Furthermore, PDF uncertainties are estimated using the Hessian method [178].

In Table X, we show the results of the cross section both at LO and NLO in the SM. We can see that the NLO corrections imply a K-factor of about 1.17 in the case when no cuts are applied 34

FIG. 11: Representative Feynman diagrams corresponding to ttH¯ 1 production at LO. They consist of production through qq¯ annihilation [diagram (a)] and through ggF [diagrams (b) and (c)].

TABLE X: Parton level cross sections for the production of ttH¯ 1 final states at the LHC at LO and Next-to- Leading Order (NLO). The results are shown along with the theoretical uncertainties due to scale variations (first errors) and PDF uncertainties (second errors). The cross sections were computed for the cases of no H H cuts on the Higgs boson pT (first row), for pT > 50 GeV (second row) and for pT > 200 GeV (third row).

σLO [fb] σNLO [fb] +32.7% +1.91% +5.8% +2.2% No cuts 398.9−22.9% (scale)−1.54% (PDF) 470.6−9.0% (scale)−2.1% (PDF) H +32.8% +1.96% +5.4% +2.3% pT > 50 GeV 325.2−22.9% (scale)−1.56% (PDF) 382.8−8.8% (scale)−2.1% (PDF) H +33.9% +2.44% +8.3% +2.9% pT > 200 GeV 55.6−23.5% (scale)−1.81% (PDF) 69.8−10.6% (scale)−2.6% (PDF)

H on the Higgs boson transverse momentum and for the case where pT > 50 GeV. The K-factor H slightly increase to 1.25 when a more stringent cut (pT > 200 GeV) is applied. Furthermore, the theoretical uncertainties are dominated by those associated to scale variations which significantly decrease when we go from LO to NLO. PDF uncertainties are subleading and mildly dependent on the Higgs pT cut. Finally, we notice that the ggF contribution is dominant accounting for 68 ( 71.5%), at LO (NLO), of the total cross section in the case of pH > 50 GeV and slightly ' ' T decreasing to 59% ( 67%) for the pH > 200 GeV case. ' ' T In the complex 2HDM, the ttH¯ 1 coupling is given by

mt ¯ = (ct, t¯LtRH + H.c.) , (86) LttH1 − v 1 1 with ct, = cα sβ α /sβ isα /tβ is the ttH¯ coupling modifier which is independent on the Yukawa- 1 2 + 1 − 2 1 realisation of the 2HDM. The ttH¯ 1 production cross section behaves as shown in Equation 62. The presence of the pseudoscalar part in the ttH¯ 1 coupling can drastically changes the value of the 35

∗ FIG. 12: The Real (left) and imaginary (right) parts of the ratio ct,1/ct,1 projected on the mixing angles

α1 and α2 upon fixing β = 0.76. The solid, dashed, dotted and dot-dashed lines show the contours where σ (pp ttH¯ )/σ (pp ttH¯ ) is 0.01, 0.1, 1 and 2, respectively. 2HDM → 1 SM → 1

π π 2 2

0.75 0.75

π π 4 0.50 4 0.50

0.25 0.25 ) ) 1 t t, /c /c 2 2 1 ∗ t 0.00 0.00 ∗ t, α

c 0 α 0 c Im( Re( 0.25 0.25 − −

π π 0.50 4 0.50 − 4 − − −

0.75 0.75 − −

π π 2 1.00 2 1.00 − π π π π − − π π π π − 0 2 4 0 4 2 − 2 − 4 4 2 − − α1 α1 cross section as can be seen in Figure 12.

C. CP-violation Observables in the ttH¯ 1 Channel

In this section, we give an overview of the different observables that we have used in this study to pin-down the spin and CP properties of the SM-like Higgs boson produced in association with a tt¯ pair. First, one can study directly the spin-spin correlations of the tt¯pair by measuring the differential distribution in cos θ`a cos θ`b of the emerging leptons,

1 d2σ 1 = 1 + α`a Pa cos θ`a + α`b Pb cos θ`b + α`a α`b Cab cos θ`a cos θ`b , (87) σ d cos θ a d cos θ b 4 ` `   ˆa,b ˆ ˆa,b where α` is the spin analyzing power of the charged lepton and θ`a,b = ](` , Sa,b), with ` being the direction of flight of the charged lepton in the top quark rest frame and Sˆa,b the spin quantization axis in the basis a. Furthermore, Cab is the correlation coefficient which is related to the expectation value of cos θ`a cos θ`b using Equation 87. In the following, we consider three different bases: the helicity basis (a = k), the transverse basis (a = n) and the r-basis, see, e.g., [19, 179] for more details about the definitions of the spin bases and [180, 181] for reported measurements of these observables in tt¯ production. It was found that the tt¯ spin-spin correlations in the transverse and r-bases are good probes of CP-violation, e.g., through the anomalous chromomagnetic and 36 chromoelectric top quark couplings [179]21. Furthermore, we consider the opening angle between the two oppositely charged leptons produced in the decays of the top (anti)quarks which is defined by

pˆ`+ pˆ`− cos ϕ`a`b = · , (88) pˆ + pˆ − | ` || ` | + wherep ˆ`+ (ˆp`− ) is the direction of the flight of the charged lepton ` (`−) in the parent top (anti)quark rest frame.

The azimuthal angle ∆φ + − = φ` φ − is a clean observable to measure the spin-spin ` ` | + − ` | correlations between the top and the antitop quarks. The momenta of the charged leptons are usually measured in the laboratory frame [182, 183]. This observable shows a high sensitivity to the degree of correlations between the top (anti)quarks in tt¯ production. However, since we are considering the ttH¯ 1 production mode, the presence of the Higgs boson may wash out the sensitivity of ∆φ to the correlations, though we have found this not to be the case. In addition to the aforementioned observables, we also study the sensitivity of the following angle [22]

− (ˆp`+ pˆH1 ) (ˆp` pˆH1 ) cos θ`H1 = × · × , (89) (ˆp + pˆH ) (ˆp − pˆH ) | ` × 1 || ` × 1 |

− wherep ˆ`+ ,p ˆ` andp ˆH1 are the directions of flight of the postively-, negatively charged lepton and of the reconstructed Higgs boson in the laboratory frame. The θ`H1 angle defines the angle spanned by the charged lepton momenta projected onto the plane perpendicular to the Higgs boson direction of flight. This observable can be redefined to yield better dependence on the CP -violating effects in the ttH¯ 1 coupling. We define the new observable as

˜ cos θ`H1 = λ cos θ`H1 , (90) with λ = sign((~pb ~p¯) (~p − ~p + )). − b · ` × ` One can obtain the polarization of the (anti)top quark by integrating Equation 87 over the a b angle θ` (or θ`):

1 dσ 1 a a = 1 + α ± P cos θ ± , (91) σ d cos θa 2 ` t,t¯ ` `±   which applies to all the spin quantization axes used here.

21 In ttH¯ 1 production, the contribution of ggF is about 70% of the total cross section. Hence, the initial state is mostly Bose-symmetric. Following the recommendations of [179], the value of cos θ` is multiplied by the sign of the ¯ scattering angle ϑ = pˆ · pˆt with pˆt = pt/|pt| the top quark direction of flight in the tt rest frame and pˆ = (0, 0, 1). 37

FIG. 13: Differential distributions for some selected observables. Top panels: we display the differential cross n n section versus ∆φ + (left) in the laboratory frame, and versus cos θ cos θ (right) with cos θ is defined | ` `− | ` ` ` in the top quark rest frame. Middle panels: we show the differential cross sections versus the cosine of the opening angle between the two charged leptons’ direction of flight (left) and versus cos θ˜`H (right). Bottom panels: The differential cross section as a function of cos ω6 (left) and as a function of the anti-symmetric k n combination of cos θ` cos θ` (right). Red lines are for the SM, blue lines are for the signal benchmark point with α2 = 0.27 while green lines are for the pure pseudoscalar case α2 = π/2 as a comparison, which is of course excluded. The differential distributions are normalized to their total cross sections.

7 [fb] ) [fb]

SM 2 − n ℓ 1 ℓ 6 α2 =0.27 θ 10 + ℓ

φ α = π/2 2 cos 1 ∆ n ℓ 5 θ d σ/

d 4 d(cos σ/

3 d SM 1 2 α2 =0.27 α2 = π/2 1

0 0 0.5 1 1.5 2 2.5 3 -1 -0.5 0 0.5 1 n n ∆φ + cos θ cos θ ℓ ℓ− ℓ1 ℓ2

[fb] SM [fb] SM ℓℓ ℓH ϕ ˜ α2 =0.27 θ α2 =0.27 1 10 1 α2 = π/2 10 α2 = π/2 dcos dcos σ/ σ/ d d

1 -1 -0.5 0 0.5 1 -1 -0.5 0 0.5 1 ˜ cos ϕℓℓ cos θℓH

20 [fb] ) [fb] 6 SM 1 2

ω 10 k ℓ

α2 =0.27 θ α = π/2 2 cos

dcos 15 1 n ℓ σ/ θ d cos

10 − 2 n ℓ θ

cos SM 1 k ℓ

5 θ α2 =0.27 1 α2 = π/2 d(cos σ/

0 d -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 -1 -0.5 0 0.5 1 cos ω cos θk cos θn cos θn cos θk 6 ℓ1 ℓ2 − ℓ1 ℓ2

It was also found that the energy distributions of the top quark decay products carry some information on the polarization state of the top (anti)quark [184–192]. We follow the same 38 definitions used by [186, 188] and study the ratios of the different energies. We give the first two observables as follows

E E u = ` , z = b , (92) E` + Eb Et where E`, Eb and Et are the energies of the charged lepton, b-jet and top quark in the laboratory frame. Finally, we consider the energy of the charged leptons in the laboratory frame

2E` x` = , (93) mt where mt = 172.5 GeV is the pole mass of the top quark.

We complement this analysis by including the sensitivity of some laboratory frame observables introduced in [30]. We found that the observable denoted by ω6 has higher sensitivity than the X,Y others (defined in [30] by ωb,` ). We define this angle by

[(~p`− ~p`+ ) (~pb + ~p¯b)][(~p`− ~p`+ ) (~pb + ~p¯b)] cos ω6 = × · − · (94) ~p − ~p + ~pb + ~p¯ ~p − ~p + ~pb + ~p¯ | ` × ` || b|| ` − ` || b| In Figure 13, we show some observables used in our analysis for the ttH¯ in the SM, and in the

2HDM with α2 = 0.27 (green) and α2 = π/2. The latter case is shown for comparison only. We can see from Figure 13 that the shape of all these observables are slightly changed as we go from the SM to the 2HDM with α2 = 0.27. The only difference between the two cases reside in the total normalization which depends on the cross section.

D. Results

In this subsection, we show the results of the sensitivity of the observables defined in the previous section. In order to quantify the sensitivity of the various spin observables to the benchmark points, we compute forward-backward asymmetries. An asymmetry on the observable is defined by AO O + N( > c) N( < c) N N − = O O − O O + − , (95) AO N( > c) + N( < c) ≡ N + N O O O O − where c is a reference point for the observable with respect to which the asymmetry is evaluated. O O For the observable ∆φ + − , we choose c = π/2. While for other angular (energy) observables, | ` ` | O we choose c = 0 ( c = 0.5). O O To quantify deviations from the SM expectations, we compute the χ2 as

SM 2 2 ( ) χ = AO − AO , (96) σ2 O 39 with σ the uncertainty on the measurement of the asymmetry in the SM. We assume that the O + N and N − are correlated, i.e. measured in the same run of an experiment. In this case, the uncertainty on the asymmetry is given by 4N +N σ2 = − , (97) O N 3 where N = A σ . Here, A  is the acceptance times the efficiency of the signal process × × L × after full selection, and σ is the cross section times the BRs, i.e.,

σ = σ(ttH¯ ) BR(H b¯b) BR(t b`ν)2. (98) 1 × 1 → × → 1 In Table XI, we show the expected deviations from the SM expectation at = 3000 fb− . L 2 We can see that, for α2 = 0.27, the χ can be larger than 1 for seven observables: k n n k r n n r cos ϕ``, x`, c c c c , c c c c , ∆φ + − , cos θ˜`H , and cos ω . After combining all the observables ` ` − ` ` ` ` − ` ` | ` ` | 6 in Table XI, the χ2 can reach about 19.2. However, the naive χ2 combination may become obsolete, or misleading. In order to improve this combination, we compute the p-value given by

∞ p = f(x, NDoF)dx (99) χ2 Z min 2 22 with f(x, NDoF) is the χ probability distribution function for NDoF degrees of freedom , and χ2 χ2 . The p-value gives to what extent the null hypothesis (SM CP -conserving case) min ≡ α2=0.27 is excluded. Values of p-value smaller than 0.05 implies that the null hypothesis is excluded. We show the p-value as a function of α2 in Table XI. In Table XI, the label Combined refers to the combination of different asymmetries for each category removing observables with χ2 < 1: (i)

In the Polarisation observables, Combined refers to the combination of cos ϕ`` and x`; (ii) while in the Spin-Spin correlation observables, Combined refers to the combination of three observables: k n n k r n n r c c c c , c c c c and ∆φ + − . As we can see that the important role played by the spin-spin ` ` − ` ` ` ` − ` ` | ` ` | correlations asymmetries for which the p-value is about 1.59 10 2. The results depends weakly on × − β and α in our favored region (tβ 1 and α 0), because the observables are sensitive only to 1 ∼ 1 ∼ the ttH¯ CP-violating phase sα /tβ in this region. It is worth to mention that the results can be 1 ' 2 further improved by using different approaches. On the one hand, the weighted fits, as used in [30], may improve the results since another important factor which we did not take advantage of is the total cross section for a given value of α2. On the other hand, methods based on Machine Learning may play important role in the determination of the maximum allowed CP -violating phase in the ttH¯ 1 coupling [193].

22 The number of degrees of freedom (NDoF) is the number of observables used in the fit minus the number of free parameters (i.e., here we have one free parameter, α2). 40

2 TABLE XI: The asymmetries for the SM and 2HDM with α2 = 0.27. The values of the χ quantifying the deviations from the SM expectations are shown in the fourth column. The p-value for different asymmetries, defined in Equation 99, are given in the fifth column. The computations are performed for an integrated luminosity of 3000 fb−1. The shorthand notations cr = cos θk , are used. Details about the calculations `+ `+ ··· are discussed in the text. Observable χ2 p-value ASM Aα2=0.27 Polarisation observables cos θk 4.12 10−3 5.32 10−3 6.34 10−3 0.937 ` × × × cos θn 4.74 10−3 4.79 10−3 8.34 10−6 0.997 ` × × × cos θr 6.54 10−4 9.31 10−3 0.33 0.565 ` − × − × cos ϕ 3.77 10−2 6.01 10−2 2.21 0.136 `` × × u 0.232 0.237 0.10 0.751 x 0.832 0.822 1.26 0.259 ` − − z 0.387 0.401 0.93 0.332 − − Combined 6.19 10−2 × Spin-Spin correlations observables cos θ 7.84 10−2 6.68 10−2 0.59 0.43 `H − × − × cos θk cos θk 6.79 10−3 1.49 10−2 0.28 0.59 ` ` × × cos θn cos θn 7.09 10−2 7.69 10−2 0.15 0.69 ` ` × × cos θr cos θr 2.98 10−2 3.01 10−2 1.74 10−4 0.98 ` ` × × × ckcn cnck 8.16 10−3 1.22 10−2 1.83 0.17 ` ` − ` ` − × × ckcn + cnck 6.28 10−3 1.97 10−2 0.79 0.37 ` ` ` ` − × − × ckcr crck 3.15 10−3 7.98 10−3 0.54 0.46 ` ` − ` ` × − × ckcr + ckck 3.25 10−2 3.99 10−2 0.24 0.62 ` ` ` ` − × − × crcn cncr 8.88 10−4 1.73 10−2 1.18 0.27 ` ` − ` ` − × − × crcn + cncr 2.53 10−3 9.31 10−3 0.61 0.43 ` ` ` ` − × × −2 ∆φ + 0.39 0.35 5.81 1.59 10 | ` `− | × Combined 1.21 10−2 × CP -odd laboratory-frame observables cos θ˜ 1.2 10−2 3.99 10−3 1.14 0.28 `H − × × cos ω 6.11 10−3 1.38 10−2 1.75 0.18 6 − × × Combined 8.89 10−2 × All the combinations 1.87 10−2 × 41

VI. CONCLUSIONS

In this work, we have analyzed soft CP-violating effects in both EDMs and LHC phenomenology in a 2HDM with soft CP-violation. In this scenario, the mixing angle α2 is the key parameter measuring the size of CP-violation since the CP-violating phases in H1ff¯ Yukawa vertices are proportional to sα2 . We have considered all four standard types of Yukawa couplings, named Type I-IV models, in our analysis. In Type I and IV models, there is no cancellation mechanism in electron EDM calculations, leading to a very strict constraint on the CP-violating phase arg c 8.2 10 4, | t/τ,1| . × − which renders all CP-violating effects unobservable in further collider studies for these two models.

In Type II and III models, we have discussed two scenarios: (a) H2,3 are closed in mass while

α3 is away from 0 or π/2; and (b) H2,3 have a large mass splitting while α3 must appear close to 0 or π/2. The cancellation behavior in the electron EDM leads to a larger allowed region for α2 in both scenarios. In such two models, tβ is favored to be close to 1, whose location depends weakly on the masses of the heavy (pseudo)scalars, with a strong correlation with α1. The electron EDM alone cannot set constraints on α directly. In the Type II model, α 0.09 is estimated from 2 | 2| . the neutron EDM constraint if we consider only the central value estimation, and this constraint can be as weak as . 0.15 if theoretical uncertainty in neutron EDM estimation is also considered. In the Type III model, no constraint can be drawn from the neutron EDM and α 0.27 is | 2| . estimated from LHC constraints if m 500 GeV. Such results mean that in Type III model, both 2 ' Scenario (a) and (b), the CP-violation phase arg(ct, ) sα /tβ can reach as large as 0.28, | 1 | ' | 2 | ' which leads us to consider further phenomenology of the model. This result is independent on α3, and depends weakly on α1 in its allowed region (close to zero). Other LHC direct searches do not set further limits for the 2HDM. Our analysis shows the importance of further neutron EDM measurements to an accuracy of (10 27 e cm). An α of the size (0.1) will lead to significant non-zero results in such O − · 2 ∼ O experiments. If CP-violation in the Higgs sector exists, as we have discussed, first evidence of it is expected to appear in the neutron EDM measurements. Conversely, if there is still a null result for the neutron EDM, direct constraints on α can be pushed to about 4 10 3 in the | 2| × − Type II model and 2 10 2 in the Type III model. Such a strict constraint can exclude the Type × − II model as an explanation of matter-antimatter asymmetry in the Universe. Thus, we conclude that, for models in which a cancellation mechanism can appear in the electron EDM, the neutron EDM measurements are good supplements to find evidence of CP-violation or set constraints on 42 the CP-violating angle directly. We have also performed a phenomenological study of soft CP-violation in the 2HDM for the case 1 of ttH¯ 1 associate production at the LHC with a luminosity of 3000 fb− . With fixed β and α1,2, its properties are independent of the mixing angle α3 and the masses of the heavy (pseudo)scalars H2,3 and H±. Upon choosing the bencdhmark point β = 0.76, α1 = 0.02 and α2 = 0.27 (corresponding to the case m , 500 GeV with the maximal CP-violation phase arg(ct, ) 0.28 in Type III 2 3 ' | 1 | ' model), we constructed top (anti)quark spin dependent observables and tested their deviations from the SM. Amongst these, a single observable, the azimuthal angle between the two leptons 2 from fully leptonic tt¯decays, ∆φ`+`− , is the most sensitive one, with χ = 5.81. On the other hand, by combining asymmetries constructed out of seven spin-dependent observables, we found that the p-value is about 1.87 10 2 meaning that the null hypothesis (the CP -conserving case) can be × − excluded by the use of these observables and one can probe the maximum allowed CP -violating phase in the ttH¯ 1 coupling obtained for α2 = 0.27. Thus the LHC experiments can provide a complementary cross-check of the EDM results. Finally, we note that we did not perform phenomenological study of the heavy (pseudo)scalars

(H2,3 or H±) in this paper. In this case, interference effects with the SM backgrounds may become very important, and thus need a dedicated treatment which we postpone for a forthcoming paper.

Acknowledgements

We thank Abdesslam Arhrib, Jianqi Chen, Nodoka Yamanaka, Fa Peng Huang, Qi-Shu Yan, Hao Zhang, and Shou-hua Zhu for helpful discussion. We also thank Abdesslam Arhrib for collaboration at the beginning of this project. The work of KC and YNM was supported in part by the MoST of Taiwan under the grant no. 107-2112-M-007-029-MY3. The work of AJ was supported by the National Research Foundation of Korea under grant no. NRF-2019R1A2C1009419. AJ would like to thank the CERN Theory Department and the HECAP Section of the Abdus Salam International Centre for Theoretical Physics for their hospitality where part of this work has been done. SM is supported in part through the NExT Institute and the STFC CG ST/L000296/1 award.

Appendix A: Yukawa Couplings

Following the parameterization in Equation 18, we list the Yukawa couplings in the mass X eigenstate basis explicitly [78–80] in terms of the mixing angles β, α1,2,3. By denoting with cf,i 43

the Yukawa coupling cf,i in the 2HDM Type X (X = I IV) below, we have the following: −

cα sβ α sα cI IV = 2 + 1 i 2 , (A1) U−i,1 sβ − tβ cβ α cα sβ α sα sα cα sα cI IV = + 1 3 + 1 2 3 i 2 3 , (A2) U−i,2 − sβ − tβ cβ α sα + sβ α sα cα cα cα cI IV = + 1 3 + 1 2 3 i 2 3 , (A3) U−i,3 − sβ − tβ

cα sβ α sα cI,III = 2 + 1 + i 2 , Di,1 sβ tβ cα cβ α cII,IV = 2 + 1 is t , (A4) Di,1 α2 β cβ − cβ α cα sβ α sα sα cα sα cI,III = + 1 3 + 1 2 3 + i 2 3 , Di,2 − sβ tβ sβ α cα + cβ α sα sα cII,IV = + 1 3 + 1 2 3 ic s t , (A5) Di,2 α2 α3 β − cβ − cβ α sα + sβ α sα cα cα cα cI,III = + 1 3 + 1 2 3 + i 2 3 , Di,3 − sβ tβ sβ α sα cβ α sα cα cII,IV = + 1 3 + 1 2 3 ic c t , (A6) Di,3 − α2 α3 β cβ −

I,IV cα2 sβ+α1 sα2 c` ,1 = + i , i sβ tβ

II,III cα2 cβ+α1 c` ,1 = isα2 tβ, (A7) i cβ −

I,IV cβ+α1 cα3 sβ+α1 sα2 sα3 cα2 sα3 c` ,2 = − + i , i sβ tβ

II,III sβ+α1 cα3 + cβ+α1 sα2 sα3 c` ,2 = icα2 sα3 tβ, (A8) i − cβ −

I,IV cβ+α1 sα3 + sβ+α1 sα2 cα3 cα2 cα3 c` ,3 = + i , i − sβ tβ

II,III sβ+α1 sα3 cβ+α1 sα2 cα3 c` ,3 = − icα2 cα3 tβ. (A9) i cβ − 44

Appendix B: Scalar Couplings

The scalar couplings in the potential can be expressed using the physical parameters as [78–80]

1 λ = c2 c2 m2 + (c s s + s c )2m2 1 2 2 β+α1 α2 1 β+α1 α2 α3 β+α1 α3 2 cβv  2 2 2 2 +(cβ α sα cα sβ α sα ) m s µ , (B1) + 1 2 3 − + 1 3 3 − β 1 λ = s2 c2 m2 + (c c s s s )2m2 2 2 2 β+α1 α2 1 β+α1 α3 β+α1 α2 α3 2 sβv −  2 2 2 2 +(sβ α sα cα + cβ α sα ) m c µ , (B2) + 1 2 3 + 1 3 3 − β 1 λ = s c2 m2 + (s2 s2 c2 )m2 + (s2 c2 s2 )m2 3 2 2(β+α1) α2 1 α2 α3 α3 2 α2 α3 α3 3 s2βv − −  2 2  2 2 2m µ +sα s α c (m m ) + ± − , (B3) 2 2 3 2(β+α1) 3 − 2 v2 1 2 2 2 2 2 2  2 2 2 2 λ4 = sα2 m1 + cα2 sα3 m2 + cα2 cα3 m3 + µ 2m , (B4) v2 − ± 1 λ = µ2 s2 m2 c2 s2 m2 c2 c2 m2  5 v2 − α2 1 − α2 α3 2 − α2 α3 3 i c c s m2 (c s s2 + s c s )m2 2 β β+α1 2α2 1 β+α1 2α2 α3 β+α1 α2 2α3 2 −s2βv −  2 2 2 +(sβ α cα s α cβ α s α c )m + sβ sβ α s α m + 1 2 2 3 − + 1 2 2 α3 3 + 1 2 2 1 2 2 2 2 +(cβ α cα s α sβ α s α s )m  (cβ α cα s α + sβ α s α c )m . (B5) + 1 2 2 3 − + 1 2 2 α3 2 − + 1 2 2 3 + 1 2 2 α3 3  Consider the-bounded-from-below conditions as [51]

λ > 0, λ > 0, λ > λ λ , λ + λ λ > λ λ , (B6) 1 2 3 − 1 2 3 4 − | 5| − 1 2 p p 2 2 2 2 then µ . (450 GeV) is favored and thus we choose µ = (450 GeV) in the analysis.

The couplings between neutron and charged scalars ci, are [80] ±

2 2 ci, = cβ(sβ(λ1 λ4 Re(λ5)) + cβλ3)Ri1 ± − − 2 2 +sβ(c (λ λ Re(λ )) + s λ )Ri + sβcβIm(λ )Ri , (B7) β 2 − 4 − 5 β 3 2 5 3 where R is the matrix in Equation 11. These couplings are useful in the calculations of fermionic EDMs from the contribution of a charged Higgs boson. 45

Appendix C: Loop Integrations for EDM

The loop functions in the calculation of the Barr-Zee diagrams are [53–55, 57–59, 63]:

z 1 1 2x(1 x) x(1 x) f(z) = dx − − ln − , (C1) 2 x(1 x) z z Z0 − −   z 1 1 x(1 x) g(z) = dx ln − , (C2) 2 x(1 x) z z Z0 − −   z 1 1 z x(1 x) h(z) = dx ln − 1 , (C3) 2 x(1 x) z x(1 x) z z − Z0 − −  − −    yf(x) xf(y) yg(x) xg(y) F (x, y) = − ; G(x, y) = − , (C4) y x y x − − 1 2 1 (1 x) (x 4 + x(z ,W zWH− )) x + (1 x)zWH Ha(z) = z dx − − ± − i ln − i , (C5) i x + (1 x)z x(1 x)z x(1 x)z Z0 WHi   1 − 2 − − − b x(1 x) x + (1 x)z ,i Hi (z) = 2z dx − ln − ± . (C6) 0 x + (1 x)z ,i x(1 x)z x(1 x)z Z − ± − −  −  Denoting

ax = x(1 x), b = ax/za,A = x + y/za,B = A ax,B0 = A ay, − − − A A ax A ay A C = ln 1,C0 = ln 1,C00 = ln 1 , (C7) B ax − B ax − B0 ay − the loop functions in the non-Barr-Zee type diagrams with a W boson are [55]

1 1 x − a 1 x 2C 2xy (DW )i = dx dy (3A 2xy) 3 + , (C8) −2 B B − − ax Z0 Z0   1 1 x x − 3A 2xy 1 + 3 (1 2y + B) 3A 2xy b 2ax − (DW )i = dx dyx C0 −2 + + − , (C9) " B B ! 2axB # Z0 Z0 1 1 x − 2 c x y b 1 y (DW )i = dx dy ln − 1 , (C10) ax(1 y b) 1 y b b − Z0 Z0 − −  − −  1 1 x − d 1 1 2Cax x 2CA (DW )i = dx dy 1 + 1 , (C11) −8 BzWHi − B B − B Z0 Z0      1 1 x − e 1 x (DW )i = dx dy 8 ax Z0 Z0

C0 2 x(2x 1) xax(2x 1) + Bx(3x 1) 2B 2 + − . (C12) × B2 − − − − 2B    46

The loop functions in the non-Barr-Zee type diagrams with a Z boson are instead [55]

1 1 x − a 2x x(1 x y) (DZ )i = dx dy 1 + C0 1 + − − , (C13) ax 2B Z0 Z0    1 1 x − 2 b x y b 1 y (DZ )i = dx dy ln − 1 , (C14) ax(1 y b) 1 y b b − Z0 Z0 − −  − −  1 1 x − 2 c 1 y (1 x y) (DZ )i = dx dy y x + C00 y x + − − . (C15) ay − − B0 Z0 Z0   

p p In the functions (D )i, we have za zWH while, in the functions (D )i, we have za zZH . W ≡ i Z ≡ i Last, the loop function for the Weinberg operator is [58]

1 1 (1 v)(uv)3 W (z) = 4z2 dv du − . (C16) [zv(1 uv) + (1 u)(1 v)]2 Z0 Z0 − − −

Appendix D: Loop Integrations for Higgs Production and Decay

The loop functions for Higgs production and decay are [135, 136]

x I(x) (x) = − , (D1) A0 x2 x + (x 1)I(x) (x) = − , (D2) A1 − x2 2x2 + 3x + 3(2x 1)I(x) (x) = − , (D3) A2 x2 I(x) (x) = 2 , (D4) B1 − x where

arcsin2 (√z) , z 1, I(z) = 2 ≤ (D5)  1 1+√1 z−1 ln − iπ , z > 1.  4 1 √1 z−1 − − − − h   i  47

Appendix E: Decay of Heavy (Pseudo)scalars

For heavy neutral (pseudo)scalars, we consider the decay channels H , tt,¯ W W, ZZ and 2 3 → ZH1. The partial decay widths are given by

3 1 2 2 2 2 2 3mimt 2 4mt 2 4mt ΓHi tt¯ = [Re(ct,i)] 1 + [Im(ct,i)] 1 , (E1) → 8πv2 − m2 − m2 "  i   i  # 3 2 2 2 4 mi cV,i 4mW 4mW 12mW ΓHi WW = 1 1 + , (E2) → 16πv2 − m2 − m2 m4 s i  i i  3 2 2 2 4 mi cV,i 4mZ 4mZ 12mZ ΓHi ZZ = 1 1 + , (E3) → 32πv2 − m2 − m2 m4 s i  i i  3 2 2 2 mi cV,k mZ mi ΓHi ZH1 = VS , . (E4) → 32πv2 F m2 m2  i i  Here k = i or 1, and the functions 6

2 2 3 VS(x, y) = (1 + x + y 2x 2y 2xy) 2 . (E5) F − − −

In Scenario (b), since H , have large mass splitting, we should also consider the H ZH decay. 2 3 3 → 2 Its partial width is

3 2 2 2 m3cV,1 mZ m2 ΓH3 ZH2 = VS , . (E6) → 32πv2 F m2 m2  3 3 

Thus numerically the total decay widths Γ , can reach about 20 GeV if m , 500 GeV, and they 2 3 2 3 ' ¯ both dominantly decay to tt. In Scenario (b), if m2 = 500 GeV and m3 = 650 GeV, BrH3 ZH2 → can reach about 10%. + The charged Higgs boson H decays mainly to t¯b in the small tβ region. Ignoring the coupling term proportional to mb, we have

2 2 2 3m mt mt ± ΓH+ t¯b = 2 1 2 . (E7) → 8πv tβ − m    ±  + + Besides this, H also have subdominant decay channels, like W Hi [80], yielding

m3 1 c2 2 2 V,i mW mi + + ± − ΓH W Hi = VS 2 , 2 . (E8) → 16πv2 F m m  ± ± 

For β = 0.76 and m = 600 GeV, ΓH+ t¯b = 33 GeV while the sum for all three neutral scalars ± → + + i ΓH W Hi . 5 GeV for α2 . 0.27. → | | P 48

Appendix F: Top Quark Reconstruction

For tt¯ spin-spin correlation and polarization observables in the top quark rest frame, it is mandatory to fully reconstruct the top (anti)quark four-momentum. In this regard, we employ the PseudoTop definition [177] widely used by the ATLAS and the CMS collaborations for, e.g., validation of MC event generators. We slightly modify the Rivet implementation of the CMS measurement of the tt¯ differential cross section at √s = 8 TeV [194]. We minimize the following quantity

2 2 2 2 2 K = M˜ mt + (Mj j mW ) + M˜ mt + Mp˜ mH , (F1) t` − 1 2 − th − H1 − 1     to select the hadronic, leptonic (anti)top quarks and SM-like Higgs boson decaying into b¯b. In

Equation F1, mt, mW and mH are the masses of the top quark, W boson and the Higgs boson, respectively, while t˜`(t˜h) is the momentum of the (anti)top constructed in the leptonic(hadronic) decays of the W boson, withp ˜H1 the four-momentum of the Higgs boson candidate. In the reconstruction procedure, all jets and leptons in the event are considered provided they satisfy the selection criteria which was highlighted in section V A. Validation plots for the PseudoTop reconstruction method in ttH¯ ( b¯b) (green) and the QCD-mediated ttb¯ ¯b (red) are shown in 1 → Figure 14.

0 [1] J. H. Christenson, J. W. Cronin, V. L. Fitch and R. Turlay, Evidence for the 2π Decay of the K2 Meson, Phys. Rev. Lett. 13 (1964) 138–140. [2] Particle Data Group collaboration, M. Tanabashi et al., Review of , Phys. Rev. D98 (2018) 030001. [3] LHCb collaboration, R. Aaij et al., Observation of CP Violation in Charm Decays, Phys. Rev. Lett. 122 (2019) 211803, [1903.08726]. [4] M. Kobayashi and T. Maskawa, CP Violation in the Renormalizable Theory of Weak Interaction, Prog. Theor. Phys. 49 (1973) 652–657. [5] A. G. Cohen, D. B. Kaplan and A. E. Nelson, Spontaneous baryogenesis at the weak phase transition, Phys. Lett. B263 (1991) 86–92. [6] A. G. Cohen, D. B. Kaplan and A. E. Nelson, Progress in electroweak baryogenesis, Ann. Rev. Nucl. Part. Sci. 43 (1993) 27–70, [hep-ph/9302210]. [7] D. E. Morrissey and M. J. Ramsey-Musolf, Electroweak baryogenesis, New J. Phys. 14 (2012) 125003, [1206.2942]. 49

FIG. 14: Validation plots for the PseudoTop reconstruction method in ttH¯ ( b¯b) (green) and the QCD- 1 → mediated ttb¯ ¯b (red). Here, we show the absolute value of the rapidity of the top quark (upper left), the transverse momentum of the tt¯ system (upper right), the invariant mass of the tt¯ system (middle left), the one of the reconstructed top (anti)quark (middle right), the one of the Higgs boson (lower left) and the one of the ttH¯ 1 system (lower right). | ¯ t t t 0.9 T y p | d

d ¯ ¯ ¯ ¯ 0.8 ttbb ttbb σ/ σ/ 0.005 ttH¯ d ttH¯ d 0.7 /σ /σ 1 1 0.6 0.004 0.5 0.003 0.4 0.3 0.002 0.2 0.001 0.1 0 0 0 0.2 0.4 0.6 0.8 1 1.2 1.4 0 100 200 300 400 500 ¯ y ptt (GeV) | t| T ¯ t t bW m 0.35 ¯ 0.08 ¯

d ¯ ¯

ttbb M ttbb d

σ/ ttH¯ ttH¯

d 0.07

0.3 σ/ d /σ

1 0.06 0.25 /σ 1 0.05 0.2 0.04 0.15 0.03 0.1 0.02 0.05 0.01 0 0 0 200 400 600 800 1.0 103 1.2 103 1.4 103 120 140 160 180 200 220 · · · mtt¯ (GeV) MbW (GeV) b ¯ b ¯ tH

t 0.18 M 0.012 ¯ ¯ ¯ ¯

d ttbb ttbb M

d 0.16 σ/ ttH¯ ttH¯ d 0.01 σ/ d 0.14 /σ 1 /σ 0.008 1 0.12 0.1 0.006 0.08 0.004 0.06 0.04 0.002 0.02 0 0 0 50 100 150 200 400 600 800 1.0 103 1.2 103 1.4 103 1.6 103 1.8 10 · · · · · Mb¯b (GeV) MttH¯ (GeV)

[8] I. B. Khriplovich and S. K. Lamoreaux, CP violation without strangeness: Electric dipole moments of particles, atoms, and molecules. Springer, 1997. [9] M. Pospelov and A. Ritz, Electric dipole moments as probes of new physics, Annals Phys. 318 (2005) 119–169, [hep-ph/0504231]. [10] J. Engel, M. J. Ramsey-Musolf and U. van Kolck, Electric Dipole Moments of Nucleons, Nuclei, and Atoms: The Standard Model and Beyond, Prog. Part. Nucl. Phys. 71 (2013) 21–74, [1303.2371]. 50

[11] N. Yamanaka, B. K. Sahoo, N. Yoshinaga, T. Sato, K. Asahi and B. P. Das, Probing exotic phenomena at the interface of nuclear and particle physics with the electric dipole moments of diamagnetic atoms: A unique window to hadronic and semi-leptonic CP violation, Eur. Phys. J. A53 (2017) 54, [1703.01570]. [12] M. S. Safronova, D. Budker, D. DeMille, D. F. J. Kimball, A. Derevianko and C. W. Clark, Search for New Physics with Atoms and Molecules, Rev. Mod. Phys. 90 (2018) 025008, [1710.01833]. [13] T. Chupp, P. Fierlinger, M. Ramsey-Musolf and J. Singh, Electric dipole moments of atoms, molecules, nuclei, and particles, Rev. Mod. Phys. 91 (2019) 015001, [1710.02504]. [14] ACME collaboration, V. Andreev et al., Improved limit on the electric dipole moment of the electron, Nature 562 (2018) 355–360. [15] C. A. Baker et al., An Improved experimental limit on the electric dipole moment of the neutron, Phys. Rev. Lett. 97 (2006) 131801, [hep-ex/0602020]. [16] J. M. Pendlebury et al., Revised experimental upper limit on the electric dipole moment of the neutron, Phys. Rev. D92 (2015) 092003, [1509.04411]. [17] nEDM collaboration, C. Abel et al., Measurement of the permanent electric dipole moment of the neutron, Phys. Rev. Lett. 124 (2020) 081803, [2001.11966]. [18] C. R. Schmidt and M. E. Peskin, A Probe of CP violation in top quark pair production at hadron supercolliders, Phys. Rev. Lett. 69 (1992) 410–413. [19] G. Mahlon and S. J. Parke, Angular correlations in top quark pair production and decay at hadron colliders, Phys. Rev. D53 (1996) 4886–4896, [hep-ph/9512264]. [20] P. S. Bhupal Dev, A. Djouadi, R. M. Godbole, M. M. Muhlleitner and S. D. Rindani, Determining the CP properties of the Higgs boson, Phys. Rev. Lett. 100 (2008) 051801, [0707.2878]. [21] X.-G. He, G.-N. Li and Y.-J. Zheng, Probing Higgs boson CP Properties with ttH¯ at the LHC and the 100 TeV pp collider, Int. J. Mod. Phys. A 30 (2015) 1550156, [1501.00012]. [22] F. Boudjema, R. M. Godbole, D. Guadagnoli and K. A. Mohan, Lab-frame observables for probing the top-Higgs interaction, Phys. Rev. D92 (2015) 015019, [1501.03157]. [23] M. R. Buckley and D. Goncalves, Boosting the Direct CP Measurement of the Higgs-Top Coupling, Phys. Rev. Lett. 116 (2016) 091801, [1507.07926]. [24] S. Amor Dos Santos et al., Probing the CP nature of the Higgs coupling in tth¯ events at the LHC, Phys. Rev. D96 (2017) 013004, [1704.03565]. [25] D. Azevedo, A. Onofre, F. Filthaut and R. Goncalo, CP tests of Higgs couplings in tth¯ semileptonic events at the LHC, Phys. Rev. D98 (2018) 033004, [1711.05292]. [26] W. Bernreuther, L. Chen, I. Garc´ia, M. Perell´o,R. Poeschl, F. Richard et al., CP-violating top quark couplings at future linear e+e− colliders, Eur. Phys. J. C78 (2018) 155, [1710.06737]. [27] K. Hagiwara, H. Yokoya and Y.-J. Zheng, Probing the CP properties of top Yukawa coupling at an e+e− collider, JHEP 02 (2018) 180, [1712.09953]. [28] K. Ma, Enhancing CP Measurement of the Yukawa Interactions of Top-Quark at e−e+ Collider, 51

Phys. Lett. B797 (2019) 134928, [1809.07127]. [29] M. Cepeda et al., Report from Working Group 2: Higgs Physics at the HL-LHC and HE-LHC, CERN Yellow Rep. Monogr. 7 (2019) 221–584, [1902.00134]. [30] D. A. Faroughy, J. F. Kamenik, N. Koˇsnikand A. Smolkoviˇc, Probing the CP nature of the top quark Yukawa at hadron colliders, JHEP 02 (2020) 085, [1909.00007]. [31] Q.-H. Cao, K.-P. Xie, H. Zhang and R. Zhang, A New Observable for Measuring CP Property of Top-Higgs Interaction, 2008.13442. [32] K. Desch, A. Imhof, Z. Was and M. Worek, Probing the CP nature of the Higgs boson at linear colliders with tau spin correlations: The Case of mixed scalar - pseudoscalar couplings, Phys. Lett. B579 (2004) 157–164, [hep-ph/0307331]. [33] S. Berge, W. Bernreuther and J. Ziethe, Determining the CP parity of Higgs bosons at the LHC in their tau decay channels, Phys. Rev. Lett. 100 (2008) 171605, [0801.2297]. [34] R. Harnik, A. Martin, T. Okui, R. Primulando and F. Yu, Measuring CP Violation in h τ +τ − at → Colliders, Phys. Rev. D88 (2013) 076009, [1308.1094]. [35] S. Berge, W. Bernreuther and H. Spiesberger, Higgs CP properties using the τ decay modes at the ILC, Phys. Lett. B727 (2013) 488–495, [1308.2674]. [36] S. Berge, W. Bernreuther and S. Kirchner, Determination of the Higgs CP-mixing angle in the tau decay channels at the LHC including the Drell–Yan background, Eur. Phys. J. C 74 (2014) 3164, [1408.0798]. [37] S. Berge, W. Bernreuther and S. Kirchner, Prospects of constraining the Higgs boson’s CP nature in the tau decay channel at the LHC, Phys. Rev. D92 (2015) 096012, [1510.03850]. [38] A. Askew, P. Jaiswal, T. Okui, H. B. Prosper and N. Sato, Prospect for measuring the CP phase in the hττ coupling at the LHC, Phys. Rev. D91 (2015) 075014, [1501.03156]. [39] K. Hagiwara, K. Ma and S. Mori, Probing CP violation in h τ −τ + at the LHC, Phys. Rev. Lett. → 118 (2017) 171802, [1609.00943]. [40] R. J´ozefowicz, E. Richter-Was and Z. Was, Potential for optimizing the Higgs boson CP measurement in H ττ decays at the LHC including machine learning techniques, Phys. Rev. D94 → (2016) 093001, [1608.02609]. [41] ATLAS collaboration, G. Aad et al., Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC, Phys. Lett. B716 (2012) 1–29, [1207.7214]. [42] CMS collaboration, S. Chatrchyan et al., Observation of a New Boson at a Mass of 125 GeV with the CMS Experiment at the LHC, Phys. Lett. B716 (2012) 30–61, [1207.7235]. [43] ATLAS, CMS collaboration, G. Aad et al., Combined Measurement of the Higgs Boson Mass in pp Collisions at √s = 7 and 8 TeV with the ATLAS and CMS Experiments, Phys. Rev. Lett. 114 (2015) 191803, [1503.07589]. [44] G. Li, Y.-n. Mao, C. Zhang and S.-h. Zhu, Testing CP violation in the scalar sector at future e+e− colliders, Phys. Rev. D95 (2017) 035015, [1611.08518]. 52

[45] Y.-n. Mao, Spontaneous CP-violation in the Simplest Little Higgs Model and its Future Collider Tests: the Scalar Sector, Phys. Rev. D97 (2018) 075031, [1703.10123]. [46] Y.-n. Mao, Spontaneous CP-violation in the Simplest Little Higgs Model, PoS ICHEP2018 (2019) 003, [1810.03854]. [47] L. Bento, G. C. Branco and P. A. Parada, A Minimal model with natural suppression of strong CP violation, Phys. Lett. B267 (1991) 95–99. [48] T. D. Lee, A Theory of Spontaneous T Violation, Phys. Rev. D8 (1973) 1226–1239. [49] T. D. Lee, CP Nonconservation and Spontaneous Symmetry Breaking, Phys. Rept. 9 (1974) 143–177. [50] H. Georgi, A Model of Soft CP Violation, Hadronic J. 1 (1978) 155. [51] G. C. Branco, P. M. Ferreira, L. Lavoura, M. N. Rebelo, M. Sher and J. P. Silva, Theory and phenomenology of two-Higgs-doublet models, Phys. Rept. 516 (2012) 1–102, [1106.0034]. [52] S. Weinberg, Gauge Theory of CP Violation, Phys. Rev. Lett. 37 (1976) 657. [53] S. M. Barr and A. Zee, Electric Dipole Moment of the Electron and of the Neutron, Phys. Rev. Lett. 65 (1990) 21–24. [54] D. Chang, W.-Y. Keung and T. C. Yuan, Two loop bosonic contribution to the electron electric dipole moment, Phys. Rev. D43 (1991) R14–R16. [55] R. G. Leigh, S. Paban and R. M. Xu, Electric dipole moment of electron, Nucl. Phys. B352 (1991) 45–58. [56] M. Jung and A. Pich, Electric Dipole Moments in Two-Higgs-Doublet Models, JHEP 04 (2014) 076, [1308.6283]. [57] T. Abe, J. Hisano, T. Kitahara and K. Tobioka, Gauge invariant Barr-Zee type contributions to fermionic EDMs in the two-Higgs doublet models, JHEP 01 (2014) 106, [1311.4704]. [58] J. Brod, U. Haisch and J. Zupan, Constraints on CP-violating Higgs couplings to the third generation, JHEP 11 (2013) 180, [1310.1385]. [59] K. Cheung, J. S. Lee, E. Senaha and P.-Y. Tseng, Confronting Higgcision with Electric Dipole Moments, JHEP 06 (2014) 149, [1403.4775]. [60] C.-Y. Chen, S. Dawson and Y. Zhang, Complementarity of LHC and EDMs for Exploring Higgs CP Violation, JHEP 06 (2015) 056, [1503.01114]. [61] V. Keus, S. F. King, S. Moretti and K. Yagyu, CP Violating Two-Higgs-Doublet Model: Constraints and LHC Predictions, JHEP 04 (2016) 048, [1510.04028]. [62] D. Fontes, J. C. Rom˜ao,R. Santos and J. P. Silva, Large pseudoscalar Yukawa couplings in the complex 2HDM, JHEP 06 (2015) 060, [1502.01720]. [63] W. Altmannshofer, J. Brod and M. Schmaltz, Experimental constraints on the coupling of the Higgs boson to electrons, JHEP 05 (2015) 125, [1503.04830]. [64] C.-Y. Chen, H.-L. Li and M. Ramsey-Musolf, CP-Violation in the Two Higgs Doublet Model: from the LHC to EDMs, Phys. Rev. D 97 (2018) 015020, [1708.00435]. [65] D. Fontes, M. M¨uhlleitner,J. C. Rom˜ao,R. Santos, J. P. Silva and J. Wittbrodt, The C2HDM 53

revisited, JHEP 02 (2018) 073, [1711.09419]. [66] E. J. Chun, J. Kim and T. Mondal, Electron EDM and Muon anomalous in Two-Higgs-Doublet Models, JHEP 12 (2019) 068, [1906.00612]. [67] S. Inoue, M. J. Ramsey-Musolf and Y. Zhang, CP-violating phenomenology of flavor conserving two Higgs doublet models, Phys. Rev. D 89 (2014) 115023, [1403.4257]. [68] Y.-n. Mao and S.-h. Zhu, Lightness of Higgs boson and spontaneous CP violation in the Lee model, Phys. Rev. D90 (2014) 115024, [1409.6844]. [69] L. Bian, T. Liu and J. Shu, Cancellations Between Two-Loop Contributions to the Electron Electric Dipole Moment with a CP-Violating Higgs Sector, Phys. Rev. Lett. 115 (2015) 021801, [1411.6695]. [70] Y.-n. Mao and S.-h. Zhu, Lightness of a Higgs Boson and Spontaneous CP-violation in the Lee Model: An Alternative Scenario, Phys. Rev. D94 (2016) 055008, [1602.00209]. [71] L. Bian and N. Chen, Higgs pair productions in the CP-violating two-Higgs-doublet model, JHEP 09 (2016) 069, [1607.02703]. [72] L. Bian and N. Chen, Cancellation mechanism in the predictions of electric dipole moments, Phys. Rev. D95 (2017) 115029, [1608.07975]. [73] D. Egana-Ugrinovic and S. Thomas, Higgs Boson Contributions to the Electron Electric Dipole Moment, 1810.08631. [74] K. Fuyuto, W.-S. Hou and E. Senaha, Cancellation mechanism for the electron electric dipole moment connected with the of the Universe, Phys. Rev. D 101 (2020) 011901, [1910.12404]. [75] J. Shu and Y. Zhang, Impact of a CP Violating Higgs Sector: From LHC to Baryogenesis, Phys. Rev. Lett. 111 (2013) 091801, [1304.0773]. [76] G. W. S. Hou, ElectroWeak BaryoGenesis via Top Transport, PoS EPS-HEP2017 (2017) 444, [1709.01262]. [77] K. Fuyuto, W.-S. Hou and E. Senaha, Electroweak baryogenesis driven by extra top Yukawa couplings, Phys. Lett. B 776 (2018) 402–406, [1705.05034]. [78] A. W. El Kaffas, W. Khater, O. M. Ogreid and P. Osland, Consistency of the two Higgs doublet model and CP violation in top production at the LHC, Nucl. Phys. B775 (2007) 45–77, [hep-ph/0605142]. [79] P. Osland, P. N. Pandita and L. Selbuz, Trilinear Higgs couplings in the two Higgs doublet model with CP violation, Phys. Rev. D78 (2008) 015003, [0802.0060]. [80] A. Arhrib, E. Christova, H. Eberl and E. Ginina, CP violation in charged Higgs production and decays in the Complex Two Higgs Doublet Model, JHEP 04 (2011) 089, [1011.6560]. [81] Belle collaboration, A. Abdesselam et al., Measurement of the inclusive B X γ branching → s+d fraction, photon energy spectrum and HQE parameters, in Proceedings, 38th International Conference on High Energy Physics (ICHEP 2016): Chicago, IL, USA, August 3-10, 2016, 2016, 1608.02344. [82] T. Hermann, M. Misiak and M. Steinhauser, B¯ X γ in the Two Higgs Doublet Model up to → s 54

Next-to-Next-to-Leading Order in QCD, JHEP 11 (2012) 036, [1208.2788]. [83] M. Misiak et al., Updated NNLO QCD predictions for the weak radiative B-meson decays, Phys. Rev. Lett. 114 (2015) 221801, [1503.01789]. Weak radiative decays of the B meson and bounds on in the [84] M. Misiak and M. Steinhauser, MH± Two-Higgs-Doublet Model, Eur. Phys. J. C77 (2017) 201, [1702.04571]. [85] M. E. Peskin and T. Takeuchi, A New constraint on a strongly interacting Higgs sector, Phys. Rev. Lett. 65 (1990) 964–967. [86] M. E. Peskin and T. Takeuchi, Estimation of oblique electroweak corrections, Phys. Rev. D46 (1992) 381–409. [87] J. de Blas, M. Ciuchini, E. Franco, S. Mishima, M. Pierini, L. Reina et al., Electroweak precision observables and Higgs-boson signal strengths in the Standard Model and beyond: present and future, JHEP 12 (2016) 135, [1608.01509]. [88] W. Grimus, L. Lavoura, O. M. Ogreid and P. Osland, A Precision constraint on multi-Higgs-doublet models, J. Phys. G35 (2008) 075001, [0711.4022]. [89] W. Grimus, L. Lavoura, O. M. Ogreid and P. Osland, The Oblique parameters in multi-Higgs-doublet models, Nucl. Phys. B801 (2008) 81–96, [0802.4353]. [90] H. E. Haber and D. O’Neil, Basis-independent methods for the two-Higgs-doublet model III: The CP-conserving limit, custodial symmetry, and the oblique parameters S, T, U, Phys. Rev. D83 (2011) 055017, [1011.6188]. [91] T. Chupp and M. Ramsey-Musolf, Electric Dipole Moments: A Global Analysis, Phys. Rev. C91 (2015) 035502, [1407.1064]. [92] C. Cesarotti, Q. Lu, Y. Nakai, A. Parikh and M. Reece, Interpreting the Electron EDM Constraint, JHEP 05 (2019) 059, [1810.07736]. [93] N. Yamanaka, Analysis of the Electric Dipole Moment in the R-parity Violating Supersymmetric Standard Model, Ph.D. thesis, Osaka U., Res. Ctr. Nucl. Phys., 2013. 10.1007/978-4-431-54544-6. [94] A. Crivellin, A. Kokulu and C. Greub, Flavor-phenomenology of two-Higgs-doublet models with generic Yukawa structure, Phys. Rev. D87 (2013) 094031, [1303.5877]. [95] S. M. Barr, Measurable T and P odd electron - nucleon interactions from Higgs boson exchange, Phys. Rev. Lett. 68 (1992) 1822–1825. [96] W. Dekens, J. de Vries, M. Jung and K. K. Vos, The phenomenology of electric dipole moments in models of scalar leptoquarks, JHEP 01 (2019) 069, [1809.09114]. [97] K. Cheung, W.-Y. Keung, Y.-n. Mao and C. Zhang, Constraining CP-violating electron-gluonic operators, JHEP 07 (2019) 074, [1904.10808]. [98] X.-D. Ji, A QCD analysis of the mass structure of the nucleon, Phys. Rev. Lett. 74 (1995) 1071–1074, [hep-ph/9410274]. [99] H.-Y. Cheng and C.-W. Chiang, Revisiting Scalar and Pseudoscalar Couplings with Nucleons, JHEP 07 (2012) 009, [1202.1292]. 55

[100] R. J. Hill and M. P. Solon, Standard Model anatomy of WIMP dark matter direct detection II: QCD analysis and hadronic matrix elements, Phys. Rev. D91 (2015) 043505, [1409.8290]. [101] xQCD collaboration, Y.-B. Yang, A. Alexandru, T. Draper, J. Liang and K.-F. Liu, πN and strangeness sigma terms at the physical point with chiral fermions, Phys. Rev. D94 (2016) 054503, [1511.09089]. [102] K. Yanase, N. Yoshinaga, K. Higashiyama and N. Yamanaka, Electric dipole moment of 199Hg atom from P , CP -odd electron-nucleon interaction, Phys. Rev. D99 (2019) 075021, [1805.00419]. [103] JLQCD collaboration, N. Yamanaka, S. Hashimoto, T. Kaneko and H. Ohki, Nucleon charges with dynamical overlap fermions, Phys. Rev. D98 (2018) 054516, [1805.10507]. [104] S. Weinberg, Larger Higgs Exchange Terms in the Neutron Electric Dipole Moment, Phys. Rev. Lett. 63 (1989) 2333. [105] D. A. Dicus, Neutron Electric Dipole Moment From Charged Higgs Exchange, Phys. Rev. D41 (1990) 999. [106] E. Braaten, C.-S. Li and T.-C. Yuan, The Evolution of Weinberg’s Gluonic CP Violation Operator, Phys. Rev. Lett. 64 (1990) 1709. [107] G. Degrassi, E. Franco, S. Marchetti and L. Silvestrini, QCD corrections to the electric dipole moment of the neutron in the MSSM, JHEP 11 (2005) 044, [hep-ph/0510137]. [108] S. Aoki et al., Review of lattice results concerning low-energy particle physics, Eur. Phys. J. C77 (2017) 112, [1607.00299]. [109] Flavour Lattice Averaging Group collaboration, S. Aoki et al., FLAG Review 2019: Flavour Lattice Averaging Group (FLAG), Eur. Phys. J. C 80 (2020) 113, [1902.08191]. [110] J. Hisano, J. Y. Lee, N. Nagata and Y. Shimizu, Reevaluation of Neutron Electric Dipole Moment with QCD Sum Rules, Phys. Rev. D85 (2012) 114044, [1204.2653]. [111] D. A. Demir, M. Pospelov and A. Ritz, Hadronic EDMs, the Weinberg operator, and light gluinos, Phys. Rev. D67 (2003) 015007, [hep-ph/0208257]. [112] U. Haisch and A. Hala, Sum rules for CP-violating operators of Weinberg type, JHEP 11 (2019) 154, [1909.08955]. [113] B. Yoon, T. Bhattacharya, V. Cirigliano and R. Gupta, Neutron Electric Dipole Moments with Clover Fermions, PoS LATTICE2019 (2020) 243, [2003.05390]. [114] C. McNeile, A. Bazavov, C. T. H. Davies, R. J. Dowdall, K. Hornbostel, G. P. Lepage et al., Direct determination of the strange and light quark condensates from full lattice QCD, Phys. Rev. D87 (2013) 034503, [1211.6577]. [115] C. A. Baker et al., CryoEDM: A cryogenic experiment to measure the neutron electric dipole moment, J. Phys. Conf. Ser. 251 (2010) 012055. [116] R. Picker, How the minuscule can contribute to the big picture: the neutron electric dipole moment project at TRIUMF, JPS Conf. Proc. 13 (2017) 010005, [1612.00875]. [117] N. Ayres, Data and Systematic Error Analysis for the Neutron Electric Dipole Moment Experiment 56

at the Paul Scherrer Institute and Search for Axionlike Dark Matter, Ph.D. thesis, Sussex U., 2018-12-14. [118] C. Abel et al., The n2EDM experiment at the Paul Scherrer Institute, EPJ Web Conf. 219 (2019) 02002, [1811.02340]. [119] nEDM collaboration, M. Ahmed et al., A New Cryogenic Apparatus to Search for the Neutron Electric Dipole Moment, JINST 14 (2019) P11017, [1908.09937]. [120] B. Graner, Y. Chen, E. Lindahl and B. Heckel, Reduced Limit on the Permanent Electric Dipole Moment of Hg199, Phys. Rev. Lett. 116 (2016) 161601, [1601.04339]. [121] M. Bishof et al., Improved limit on the 225Ra electric dipole moment, Phys. Rev. C 94 (2016) 025501, [1606.04931]. [122] N. Sachdeva et al., New Limit on the Permanent Electric Dipole Moment of 129Xe using 3He Comagnetometry and SQUID Detection, Phys. Rev. Lett. 123 (2019) 143003, [1902.02864]. [123] M. Pospelov, Best values for the CP odd meson nucleon couplings from , Phys. Lett. B 530 (2002) 123–128, [hep-ph/0109044]. [124] LHC Higgs Cross Section Working Group, S. Dittmaier, C. Mariotti, G. Passarino and R. Tanaka (Eds.), Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables, CERN-2011-002 (CERN, Geneva, 2011) , [1101.0593]. [125] S. Dittmaier et al., Handbook of LHC Higgs Cross Sections: 2. Differential Distributions, 1201.3084. [126] LHC Higgs Cross Section Working Group collaboration, J. R. Andersen et al., Handbook of LHC Higgs Cross Sections: 3. Higgs Properties, 1307.1347. [127] LHC Higgs Cross Section Working Group collaboration, D. de Florian et al., Handbook of LHC Higgs Cross Sections: 4. Deciphering the Nature of the Higgs Sector, 1610.07922. [128] ATLAS collaboration, G. Aad et al., Combined measurements of Higgs boson production and decay using up to 80 fb−1 of proton-proton collision data at √s = 13 TeV collected with the ATLAS experiment, Phys. Rev. D101 (2020) 012002, [1909.02845]. [129] ATLAS, CMS collaboration, L. Cadamuro, Higgs boson couplings and properties, PoS LHCP2019 (2019) 101. [130] ATLAS collaboration, Measurement of Higgs boson production in association with a tt pair in the diphoton decay channel using 139 fb−1 of LHC data collected at √s = 13 TeV by the ATLAS experiment, Tech. Rep. ATLAS-CONF-2019-004, CERN, Geneva, Mar, 2019. [131] ATLAS collaboration, M. Aaboud et al., Observation of Higgs boson production in association with a top quark pair at the LHC with the ATLAS detector, Phys. Lett. B784 (2018) 173–191, [1806.00425]. [132] CMS collaboration, Combined Higgs boson production and decay measurements with up to 137 fb-1 of proton-proton collision data at √s = 13 TeV, Tech. Rep. CMS-PAS-HIG-19-005, CERN, Geneva, 2020. [133] CMS collaboration, A. M. Sirunyan et al., Combined measurements of Higgs boson couplings in 57

proton-proton collisions at √s = 13 TeV, Eur. Phys. J. C79 (2019) 421, [1809.10733]. [134] CMS collaboration, A. M. Sirunyan et al., Observation of Higgs boson decay to bottom quarks, Phys. Rev. Lett. 121 (2018) 121801, [1808.08242]. [135] A. Djouadi, The Anatomy of electro-weak symmetry breaking. I: The Higgs boson in the standard model, Phys. Rept. 457 (2008) 1–216, [hep-ph/0503172]. [136] A. Djouadi, The Anatomy of electro-weak symmetry breaking. II. The Higgs bosons in the minimal supersymmetric model, Phys. Rept. 459 (2008) 1–241, [hep-ph/0503173]. [137] H.-L. Li, P.-C. Lu, Z.-G. Si and Y. Wang, Associated Production of Higgs Boson and tt¯ at LHC, Chin. Phys. C40 (2016) 063102, [1508.06416]. [138] ATLAS collaboration, Search for heavy ZZ resonances in the `+`−`+`− and `+`−νν¯ final states using proton–proton collisions at √s = 13 TeV with the ATLAS detector, Tech. Rep. ATLAS-CONF-2017-058, CERN, Geneva, Jul, 2017. [139] A. D. Martin, W. J. Stirling, R. S. Thorne and G. Watt, Parton distributions for the LHC, Eur. Phys. J. C63 (2009) 189–285, [0901.0002]. [140] E. W. N. Glover and J. J. van der Bij, Z BOSON PAIR PRODUCTION VIA GLUON FUSION, Nucl. Phys. B 321 (1989) 561–590. [141] A. Pilaftsis, Resonant CP violation induced by particle mixing in transition amplitudes, Nucl. Phys. B 504 (1997) 61–107, [hep-ph/9702393]. [142] M. Berger and C. Kao, Production of Z boson pairs via gluon fusion in the minimal supersymmetric model, Phys. Rev. D 59 (1999) 075004, [hep-ph/9809240]. [143] N. Kauer, Signal-background interference in gg H VV , PoS RADCOR2011 (2011) 027, → → [1201.1667]. [144] ATLAS collaboration, M. Aaboud et al., Search for heavy particles decaying into top-quark pairs using lepton-plus-jets events in proton-proton collisions at √s = 13 TeV with the ATLAS detector, Eur. Phys. J. C78 (2018) 565, [1804.10823]. [145] D. Dicus, A. Stange and S. Willenbrock, Higgs decay to top quarks at hadron colliders, Phys. Lett. B333 (1994) 126–131, [hep-ph/9404359]. [146] A. Djouadi, J. Ellis, A. Popov and J. Quevillon, Interference effects in tt production at the LHC as a window on new physics, JHEP 03 (2019) 119, [1901.03417]. [147] S. Moretti and D. A. Ross, On the top-antitop invariant mass spectrum at the LHC from a Higgs boson signal perspective, Phys. Lett. B712 (2012) 245–249, [1203.3746]. [148] ATLAS collaboration, M. Aaboud et al., Search for Heavy Higgs Bosons A/H Decaying to a Top Quark Pair in pp Collisions at √s = 8 TeV with the ATLAS Detector, Phys. Rev. Lett. 119 (2017) 191803, [1707.06025]. [149] CMS collaboration, A. M. Sirunyan et al., Search for heavy Higgs bosons decaying to a top quark pair in proton-proton collisions at √s = 13 TeV, JHEP 04 (2020) 171, [1908.01115]. [150] CMS collaboration, Search for standard model production of four top quarks in final states with 58

same-sign and multiple leptons in proton-proton collisions at √s = 13 TeV, Tech. Rep. CMS-PAS-TOP-18-003, CERN, Geneva, 2019. [151] ATLAS collaboration, G. Aad et al., Evidence for ttt¯ t¯ production in the multilepton final state in proton-proton collisions at √s=13 TeV with the ATLAS detector, 2007.14858. [152] Q.-H. Cao, S.-L. Chen, Y. Liu, R. Zhang and Y. Zhang, Limiting top quark-Higgs boson interaction and Higgs-boson width from multitop productions, Phys. Rev. D99 (2019) 113003, [1901.04567]. [153] J. Alwall, M. Herquet, F. Maltoni, O. Mattelaer and T. Stelzer, MadGraph 5 : Going Beyond, JHEP 06 (2011) 128, [1106.0522]. [154] J. Alwall, R. Frederix, S. Frixione, V. Hirschi, F. Maltoni, O. Mattelaer et al., The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations, JHEP 07 (2014) 079, [1405.0301]. [155] CMS collaboration, A. M. Sirunyan et al., Search for a charged Higgs boson decaying into top and bottom quarks in events with electrons or muons in proton-proton collisions at √s = 13 TeV, JHEP 01 (2020) 096, [1908.09206]. [156] CMS collaboration, Search for charged Higgs bosons decaying into top and a bottom quark in the fully hadronic final state at 13 TeV, Tech. Rep. CMS-PAS-HIG-18-015, CERN, Geneva, 2019. [157] A. Arhrib, D. Azevedo, R. Benbrik, H. Harouiz, S. Moretti, R. Patrick et al., Signal versus Background Interference in H+ t¯b Signals for MSSM Benchmark Scenarios, 1905.02635. → [158] CMS Collaboration collaboration, Analysis of the CP structure of the Yukawa coupling between the Higgs boson and τ leptons in proton-proton collisions at √s = 13 TeV, Tech. Rep. CMS-PAS-HIG-20-006, CERN, Geneva, 2020. [159] C. Degrande, C. Duhr, B. Fuks, D. Grellscheid, O. Mattelaer and T. Reiter, UFO - The Universal FeynRules Output, Comput. Phys. Commun. 183 (2012) 1201–1214, [1108.2040]. [160] C. Degrande, Automatic evaluation of UV and R2 terms for beyond the Standard Model Lagrangians: a proof-of-principle, Comput. Phys. Commun. 197 (2015) 239–262, [1406.3030]. [161] L. A. Harland-Lang, A. D. Martin, P. Motylinski and R. S. Thorne, Parton distributions in the LHC era: MMHT 2014 PDFs, Eur. Phys. J. C75 (2015) 204, [1412.3989]. [162] A. Kalogeropoulos and J. Alwall, The SysCalc code: A tool to derive theoretical systematic uncertainties, 1801.08401. [163] P. Artoisenet, R. Frederix, O. Mattelaer and R. Rietkerk, Automatic spin-entangled decays of heavy resonances in Monte Carlo simulations, JHEP 03 (2013) 015, [1212.3460]. [164] T. Sj¨ostrand,S. Ask, J. R. Christiansen, R. Corke, N. Desai, P. Ilten et al., An Introduction to PYTHIA 8.2, Comput. Phys. Commun. 191 (2015) 159–177, [1410.3012]. [165] M. Dobbs and J. B. Hansen, The HepMC C++ Monte Carlo event record for High Energy Physics, Comput. Phys. Commun. 134 (2001) 41–46. [166] A. Buckley, J. Butterworth, L. L¨onnblad, D. Grellscheid, H. Hoeth, J. Monk et al., Rivet user manual, Comput. Phys. Commun. 184 (2013) 2803–2819, [1003.0694]. 59

[167] M. Cacciari, G. P. Salam and G. Soyez, The Anti-k(t) jet clustering algorithm, JHEP 04 (2008) 063, [0802.1189]. [168] M. Cacciari, G. P. Salam and G. Soyez, FastJet User Manual, Eur. Phys. J. C72 (2012) 1896, [1111.6097]. [169] G. Corcella, I. G. Knowles, G. Marchesini, S. Moretti, K. Odagiri, P. Richardson et al., HERWIG 6.5 release note, hep-ph/0210213. [170] G. Corcella, I. G. Knowles, G. Marchesini, S. Moretti, K. Odagiri, P. Richardson et al., HERWIG 6.4 release note, hep-ph/0201201. [171] G. Corcella, I. G. Knowles, G. Marchesini, S. Moretti, K. Odagiri, P. Richardson et al., HERWIG 6.3 release note, hep-ph/0107071. [172] G. Corcella, I. G. Knowles, G. Marchesini, S. Moretti, K. Odagiri, P. Richardson et al., HERWIG 6: An Event generator for hadron emission reactions with interfering gluons (including supersymmetric processes), JHEP 01 (2001) 010, [hep-ph/0011363]. [173] M. Wobisch and T. Wengler, Hadronization corrections to jet cross-sections in deep inelastic scattering, in Monte Carlo generators for HERA physics. Proceedings, Workshop, Hamburg, Germany, 1998-1999, pp. 270–279, 1998, hep-ph/9907280. [174] Y. L. Dokshitzer, G. D. Leder, S. Moretti and B. R. Webber, Better jet clustering algorithms, JHEP 08 (1997) 001, [hep-ph/9707323]. [175] M. Cacciari and G. P. Salam, Pileup subtraction using jet areas, Phys. Lett. B659 (2008) 119–126, [0707.1378]. [176] M. Cacciari, G. P. Salam and G. Soyez, The Catchment Area of Jets, JHEP 04 (2008) 005, [0802.1188]. [177] CMS collaboration, Object definitions for top quark analyses at the particle level, Tech. Rep. CMS-NOTE-2017-004, CERN-CMS-NOTE-2017-004, CERN, Geneva, Jun, 2017. [178] J. Pumplin, D. Stump, R. Brock, D. Casey, J. Huston, J. Kalk et al., Uncertainties of predictions from parton distribution functions. 2. The Hessian method, Phys. Rev. D65 (2001) 014013, [hep-ph/0101032]. [179] W. Bernreuther and Z.-G. Si, Top quark spin correlations and polarization at the LHC: standard model predictions and effects of anomalous top chromo moments, Phys. Lett. B725 (2013) 115–122, [1305.2066]. [180] ATLAS collaboration, M. Aaboud et al., Measurements of top quark spin observables in tt events using dilepton final states in √s = 8 TeV pp collisions with the ATLAS detector, JHEP 03 (2017) 113, [1612.07004]. [181] CMS collaboration, A. M. Sirunyan et al., Measurement of the top quark polarization and t¯t spin correlations using dilepton final states in proton-proton collisions at √s = 13 TeV, Phys. Rev. D100 (2019) 072002, [1907.03729]. [182] ATLAS collaboration, Measurements of top-quark pair spin correlations in the eµ channel at 60

√s = 13 TeV using pp collisions in the ATLAS detector, Tech. Rep. ATLAS-CONF-2018-027, CERN, Geneva, Jul, 2018. [183] CMS collaboration, Measurements of differential cross sections for t¯t production in proton-proton collisions at √s = 13 TeV using events containing two leptons, Tech. Rep. CMS-PAS-TOP-17-014, CERN, Geneva, 2018. [184] R. M. Godbole, L. Hartgring, I. Niessen and C. D. White, Top polarisation studies in H−t and W t production, JHEP 01 (2012) 011, [1111.0759]. [185] S. D. Rindani and P. Sharma, Probing anomalous tbW couplings in single-top production using top polarization at the Large Hadron Collider, JHEP 11 (2011) 082, [1107.2597]. [186] A. Prasath V, R. M. Godbole and S. D. Rindani, Longitudinal top polarisation measurement and anomalous W tb coupling, Eur. Phys. J. C75 (2015) 402, [1405.1264]. [187] R. M. Godbole, G. Mendiratta and S. Rindani, Looking for bSM physics using top-quark polarization and decay-lepton kinematic asymmetries, Phys. Rev. D92 (2015) 094013, [1506.07486]. [188] A. Jueid, Probing anomalous W tb couplings at the LHC in single t-channel top quark production, Phys. Rev. D98 (2018) 053006, [1805.07763]. [189] A. Arhrib, A. Jueid and S. Moretti, Top quark polarization as a probe of charged Higgs bosons, Phys. Rev. D98 (2018) 115006, [1807.11306]. [190] R. Godbole, M. Guchait, C. K. Khosa, J. Lahiri, S. Sharma and A. H. Vijay, Boosted Top quark polarization, Phys. Rev. D100 (2019) 056010, [1902.08096]. [191] A. Arhrib, A. Jueid and S. Moretti, Searching for Heavy Charged Higgs Bosons through Top Quark Polarization, Int. J. Mod. Phys. A 35 (2020) 2041011, [1903.11489]. [192] S. Chatterjee, R. Godbole and T. S. Roy, Jets with electrons from boosted top quarks, JHEP 01 (2020) 170, [1909.11041]. [193] J. Ren, L. Wu and J. M. Yang, Unveiling CP property of top-Higgs coupling with graph neural networks at the LHC, Phys. Lett. B 802 (2020) 135198, [1901.05627]. [194] CMS collaboration, V. Khachatryan et al., Measurement of the differential cross section for top quark pair production in pp collisions at √s = 8 TeV, Eur. Phys. J. C75 (2015) 542, [1505.04480].