Sterile Neutrinos As the Origin of Dark and Baryonic Matter Mikhail Shaposhnikov

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Sterile Neutrinos as the Origin of Dark and Baryonic Matter Mikhail Shaposhnikov

BNL, 21 June 2016

BNL, 21 June 2016 – p. 1 Outline

Setting up the scene: LHC and new physics

Standard Model and heavy neutral leptons (HNL or sterile neutrinos)

Dark matter from HNL

Baryon asymmetry of the Universe from HNL

How to search for HNL?

SHiP and FCC-ee

Conclusions

BNL, 21 June 2016 – p. 2 The scene : LHC discoveries

BNL, 21 June 2016 – p. 3 July 4, 2012, Higgs at ATLAS and CMS

3500 ATLAS Data Sig+Bkg Fit (m =126.5 GeV) 3000 H CMS Bkg (4th order polynomial) 2500 Events / 2 GeV 2000 1500 s=7 TeV, #Ldt=4.8fb-1 1000 s=8 TeV, #Ldt=5.9fb-1 500 H !!" (a) 200 100 0 -100

Events - Bkg (b) -200 V Data S/B Weighted 100 Sig+Bkg Fit (m =126.5 GeV) H Bkg (4th order polynomial) 80 weights / 2 Ge

$ 60

20 (c) 8 4 0 -4 (d)

$ -8 weights - Bkg 100 110 120 130 140 150 160 m !! [GeV]

BNL, 21 June 2016 – p. 4 Higgs boson properties

Atlas - MH = 125.36 ± 0.41 GeV

ATLAS Prelim. &(stat.) Total uncertainty m = 125.36 GeV sys inc. H &(theory ) ±1& on µ arXiv:1408.7084 CMS - MH = 125.03 ± 0.29 GeV + 0.23 H # "" - 0.23

) 4 +0.27 + 0.16 ATLAS Combined ## +ZZ* µ = 1.17-0.27 - 0.11 s = 7 TeV Ldt = 4.5 fb-1 H $ ## 3.5 " H $ ZZ* $ 4l s = 8 TeV Ldt = 20.3 fb-1 arXiv:1408.5191 " + 0.34 Best fit H # ZZ* # 4l - 0.31

=125.36 GeV) 3 H 68% CL

(m 95% CL +0.40 + 0.21 µ = 1.44 - 0.11 SM 2.5 -0.33 ! / arXiv:1412.2641 ! 2 + 0.16 H # WW* # l$l$ - 0.15 1.5 +0.23 + 0.17 µ = 1.09-0.21 - 0.14 1 JHEP11(2014)056 Signal yield ( 0.5 + 0.3 W,Z H # bb - 0.3

0 +0.4 + 0.2 123 123.5 124 124.5 125 125.5 126 126.5 127 127.5 µ = 0.5-0.4 - 0.2

mH [GeV] ATLAS-CONF-2014-061 + 0.3 H # %% - 0.3

+0.4 + 0.3 µ = 1.4-0.4 - 0.3 0 0.5 1 1.5 2 s = 7 TeV !Ldt = 4.5-4.7 fb-1 Signal strength (µ) s = 8 TeV Ldt = 20.3 fb-1 ! released 09.12.2014 New resonance properties are consistent with those of the Higgs

boson of the Standard Model BNL, 21 June 2016 – p. 5 Determination of top quark mass

Monte Carlo mass: mt = 172.38 ± 0.10 ± 0.65 GeV

19.7 fb-1 (8 TeV) + 5.1 fb-1 (7 TeV)

CMS Preliminary CMS 2010, dilepton 175.5 ± 4.6 ± 4.6 GeV JHEP 07 (2011) 049, 36 pb-1 (value ± stat ± syst)

10 CMS 2010, lepton+jets 173.1 ± 2.1 ± 2.6 GeV PAS TOP-10-009, 36 pb-1 (value ± stat ± syst)

CMS 2011, dilepton 172.5 ± 0.4 ± 1.4 GeV EPJC 72 (2012) 2202, 5.0 fb-1 (value ± stat ± syst)

CMS 2011, lepton+jets 173.5 ± 0.4 ± 1.0 GeV JHEP 12 (2012) 105, 5.0 fb-1 (value ± stat ± syst)

CMS 2011, all-hadronic 173.5 ± 0.7 ± 1.2 GeV EPJ C74 (2014) 2758, 3.5 fb-1 (value ± stat ± syst)

CMS 2012, lepton+jets 172.0 ± 0.1 ± 0.7 GeV PAS TOP-14-001, 19.7 fb-1 (value ± stat ± syst)

5 CMS 2012, all-hadronic 172.1 ± 0.3 ± 0.8 GeV PAS TOP-14-002, 18.2 fb-1 (value ± stat ± syst)

CMS 2012, dilepton 172.5 ± 0.2 ± 1.4 GeV PAS TOP-14-010, 19.7 fb-1 (value ± stat ± syst)

CMS combination 172.38 ± 0.10 ± 0.65 GeV September 2014 (value ± stat ± syst)

Tevatron combination 174.34 ± 0.37 ± 0.52 GeV July 2014 arXiv:1407.2682 (value ± stat ± syst) World combination March 2014 173.34 ± 0.27 ± 0.71 GeV ATLAS, CDF, CMS, D0 (value ± stat ± syst) 0 165 170 175 180 mt [GeV]

BNL, 21 June 2016 – p. 6 Important fact: The combination of top-quark and Higgs boson masses is very close to the stability bound of the SM vacuum∗ (95’), to the ∗∗ Higgs inﬂation bound (08’), and to asymptotic safety values for MH ∗∗∗ and Mt (09’):

V V V ∗ Froggatt, Nielsen ∗∗ M Bezrukov, MS crit metastability De Simone, Hertzberg, stability φ φ φ Wilczek Fermi Planck Fermi Planck Fermi Planck ∗∗∗ Wetterich, MS

BNL, 21 June 2016 – p. 7 123)%,#,&/*0 &"#)$ 4 3"#6)7'.&1 3)7"#" &"#)% 5 5 453"#6%8,.&153)7)#" &"#) 453"#6%6$.&153)7%#" &"#"( 453"#68,6.&153)78#) 453"#6$)8.&153)7$#" &"#"' 453"#6$7%.&153)7,#" ! &"#"$ &"#"% &" !"#"% !"#"$ &)""""" &)*+)" &)*+), &)*+%" -.&/*0

Absolute stability Metastability

TEVATRON 2014: mt = 174.34 ± 0.37 ± 0.52 GeV BNL, 21 June 2016 – p. 8 123)%,#,&/*0 &"#)$ 4 3"#6)7'.&1 3)7"#" &"#)% 5 5 453"#6%8,.&153)7)#" &"#) 453"#6%6$.&153)7%#" &"#"( 453"#68,6.&153)78#) 453"#6$)8.&153)7$#" &"#"' 453"#6$7%.&153)7,#" ! &"#"$ &"#"% &" !"#"% !"#"$ &)""""" &)*+)" &)*+), &)*+%" -.&/*0

Absolute stability Metastability

PDG 2014: mt = 173.34 ± 0.27 ± 0.71 GeV BNL, 21 June 2016 – p. 9 123)%,#,&/*0 &"#)$ 4 3"#6)7'.&1 3)7"#" &"#)% 5 5 453"#6%8,.&153)7)#" &"#) 453"#6%6$.&153)7%#" &"#"( 453"#68,6.&153)78#) 453"#6$)8.&153)7$#" &"#"' 453"#6$7%.&153)7,#" ! &"#"$ &"#"% &" !"#"% !"#"$ &)""""" &)*+)" &)*+), &)*+%" -.&/*0

Absolute stability Metastability

CMS 2014: mt = 172.38 ± 0.10 ± 0.65 GeV BNL, 21 June 2016 – p. 10 Buttazzo et al, ’13, ’14 Bednyakov et al, ’15

Vacuum is unstable at 2.8σ Vacuum is unstable at 1.3σ

Main uncertainty: top Yukawa coupling, relation between the MC mass and the top Yukawa coupling allows for ±1 GeV in Mtop. Alekhin et al, Frixione et al.

BNL, 21 June 2016 – p. 11 Vacuum lifetime

129

128

127

126 , GeV h 125 m

124

123 320 80 20 10 tU 10 tU 10 tU 122 170 171 172 173 174 175 176 177

mt, GeV

BNL, 21 June 2016 – p. 12 Searches for new physics, SUSY

ATLAS SUSY Searches* - 95% CL Lower Limits ATLAS Preliminary Status: ICHEP 2014 √s =7,8TeV miss 1 e,µ,τ, γ E L dt[fb− ] Model Jets T ! Mass limit Reference

MSUGRA/CMSSM 0 2-6 jets Ye s 20.3 q˜, g˜ 1.7 TeV m(q˜)=m(g˜) 1405.7875 MSUGRA/CMSSM 1 e,µ 3-6 jets Ye s 20.3 g˜ 1.2 TeV any m(q˜) ATLAS-CONF-2013-062 MSUGRA/CMSSM 0 7-10 jets Ye s 20.3 g˜ 1.1 TeV any m(q˜) 1308.1841 0 q˜ χ˜0 st nd q˜q˜, q˜ qχ˜1 0 2-6 jets Ye s 20.3 850 GeV m( 1)=0 GeV, m(1 gen. ˜q )=m(2 gen. ˜q ) 1405.7875 → 0 0 g˜g˜, g˜ qq¯χ˜ 0 2-6 jets Ye s 20.3 g˜ 1.33 TeV m(χ˜1)=0 GeV 1405.7875 ±1 ± → ± 0 g˜ χ˜0 χ˜ χ˜0 g˜g˜, g˜ qqχ˜1 qqW χ˜1 1 e,µ 3-6 jets Ye s 20.3 1.18 TeV m( 1)<200 GeV, m( )=0.5(m( 1)+m(g˜)) ATLAS-CONF-2013-062 → → 0 - g˜ χ˜0 = g˜g˜, g˜ qq(ℓℓ/ℓν/νν)χ˜1 2 e,µ 0-3 jets 20.3 1.12 TeV m( 1) 0GeV ATLAS-CONF-2013-089 GMSB→ (ℓ˜ NLSP) 2 e,µ 2-4 jets Ye s 4 . 7 g˜ 1.24 TeV tanβ<15 1208.4688 GMSB (ℓ˜ NLSP) 1-2 τ +0-1ℓ 0-2 jets Ye s 2 0 . 3 g˜ 1.6 TeV tanβ >20 1407.0603 0 GGM (bino NLSP) 2 γ - Ye s 20.3 g˜ 1.28 TeV m(χ˜1)>50 GeV ATLAS-CONF-2014-001 0 GGM (wino NLSP) 1 e,µ+ γ - Ye s 4 . 8 g˜ 619 GeV m(χ˜ )>50 GeV ATLAS-CONF-2012-144

Inclusive Searches 1 0 GGM (higgsino-bino NLSP) γ 1 b Ye s 4.8 g˜ 900 GeV m(χ˜1)>220 GeV 1211.1167 GGM (higgsino NLSP) 2 e,µ(Z) 0-3 jets Ye s 5 . 8 g˜ 690 GeV m(NLSP)>200 GeV ATLAS-CONF-2012-152 1/2 4 Gravitino LSP 0 mono-jet Ye s 10.5 F scale 645 GeV m(G˜)>10− eV ATLAS-CONF-2012-147 0 g˜ χ˜0 g˜ bb¯χ˜1 03b Ye s 2 0 . 1 1.25 TeV m( 1)<400 GeV 1407.0600 0 0 → ¯χ˜ 0 7-10 jets Ye s 20.3 g˜ 1.1 TeV m(χ˜ ) <350 GeV 1308.1841 gen. g˜ tt 1 1

med. 0 0 → ¯χ˜ 0-1 e,µ 3 b Ye s 2 0 . 1 g˜ 1.34 TeV m(χ˜ )<400 GeV 1407.0600 rd g˜ tt 1 1 ˜ g + 0 3 → ˜ g˜ bt¯χ˜1 0-1 e,µ 3 b Ye s 20.1 g 1.3 TeV m(χ˜1)<300 GeV 1407.0600 → 0 0 ˜ ˜ ˜ χ˜ 0 2 b Ye s 2 0 . 1 b˜ 1 100-620 GeV m(χ˜ )<90 GeV 1308.2631 b1b1, b1 b ±1 1 → ˜ χ± χ0 b˜1b˜1, b˜1 tχ˜1 2 e,µ(SS) 0-3 b Ye s 20.3 b1 275-440 GeV m( ˜1 )=2 m( ˜1) 1404.2500 → ± ˜ 0 t˜1t˜1(light), t˜1 bχ˜1 1-2 e,µ 1-2 b Ye s 4.7 t1 110-167 GeV m(χ˜1)=55 GeV 1208.4305, 1209.2102 → 0 ˜ χ˜0 χ˜± t˜1t˜1(light), t˜1 Wbχ˜1 2 e,µ 0-2 jets Ye s 20.3 t1 130-210 GeV m( 1) =m(t˜1)-m(W)-50 GeV, m(t˜1)<

rd 0 → 0 ˜ ˜ ˜ χ˜ 0 mono-jet/c-tag Ye s 20.3 t˜1 90-240 GeV m(t˜ )-m(χ˜ )<85 GeV 1407.0608 3 direct productiont1t1, t1 c 1 1 1 → ˜ 0 t˜1t˜1(natural GMSB) 2 e,µ(Z) 1 b Ye s 2 0 . 3 t1 150-580 GeV m(χ˜1)>150 GeV 1403.5222 0 t˜2t˜2, t˜2 t˜1 + Z 3 e,µ(Z) 1 b Ye s 20.3 t˜2 290-600 GeV m(χ˜ )<200 GeV 1403.5222 → 1 0 0 ℓ˜ ℓ˜ , ℓ˜ ℓχ˜ 2 e,µ 0Yes20.3ℓ˜ 90-325 GeV m(χ˜ )=0 GeV 1403.5294 L+,R L,R+ 1 1 → χ˜ ± 0 ± 0 χ˜ χ˜−, χ˜ ℓν˜ (ℓν˜) 2 e,µ 0 Ye s 20.3 1 140-465 GeV m(χ˜1)=0 GeV, m(ℓ˜, ν˜)=0.5(m(χ˜1 )+m(χ˜1)) 1403.5294 1+ 1 1+ ± → - χ˜ χ0 χ± χ0 χ˜ 1 χ˜1−, χ˜1 τν˜ (τν˜) 2 τ Ye s 2 0 . 3 1 100-350 GeV m( ˜1)=0 GeV, m(τ˜, ν˜)=0.5(m( ˜1 )+m( ˜1)) 1407.0350 ± 0 → ˜ ± ˜ 0 ± 0 0 ± 0 χ˜ χ˜ ℓ˜ νℓ˜ ℓ(˜νν), ℓν˜ℓ˜ ℓ(˜νν) 3 e,µ 0 Ye s 20.3 χ , χ 700 GeV m(χ˜1 )=m(χ˜2), m(χ˜1)=0, m(ℓ˜, ν˜)=0.5(m(χ˜1 )+m(χ˜1)) 1402.7029 EW 1 2 L L L 1 2 ± ± 0 ± 0 0 direct 0→ 0 0 χ˜ χ˜ χ˜ χ˜ χ˜ 1403.5294, 1402.7029 χ˜ 1 χ˜2 Wχ˜1Zχ˜ 1 2-3 e,µ 0Yes20.31 , 2 420 GeV m( 1 )=m( 2), m( 1)=0, sleptons decoupled ± 0→ 0 0 χ˜ ± χ˜ 0 χ˜± χ˜0 χ˜0 χ˜ 1 χ˜2 Wχ˜1h χ˜ 1 1 e,µ 2 b Ye s 20.3 1 , 2 285 GeV m( 1 )=m( 2), m( 1)=0, sleptons decoupled ATLAS-CONF-2013-093 0 0 →0 ˜ χ˜ 0 χ˜0 χ˜0 χ˜0 ˜ χ˜0 χ˜0 χ˜ 2χ˜ 3, χ˜ 2,3 ℓRℓ 4 e,µ 0Yes20.32,3 620 GeV m( 2)=m( 3), m( 1)=0, m(ℓ, ν˜)=0.5(m( 2)+m( 1)) 1405.5086 + → ± χ˜ ± χ± χ0 = χ± = Direct χ˜1 χ˜ 1− prod., long-lived χ˜ 1 Disapp. trk 1 jet Ye s 20.3 1 270 GeV m( ˜1 )-m( ˜1) 160 MeV, τ( ˜1 ) 0.2 ns ATLAS-CONF-2013-069 0 Stable, stopped g˜ R-hadron 0 1-5 jets Ye s 2 7 . 9 g˜ 832 GeV m(χ˜1)=100 GeV, 10 µs<τ(˜g)<1000 s 1310.6584 0 -- χ˜ 0 10

Long-lived → q˜q˜, χ˜ qqµ (RPV) 1 µ, displ. vtx --20.3 q˜ 1.0 TeV 1.5 X, ν˜τ e + µ 2 e,µ --4.6 ν˜τ 1.61 TeV λ′ =0.10, λ132=0.05 1212.1272 → → 311 LFV pp ν˜τ + X, ν˜τ e(µ) + τ 1 e,µ+ τ --4.6 ν˜τ 1.1 TeV λ′ =0.10, λ1(2)33=0.05 1212.1272 → → 311 Bilinear RPV CMSSM 2 e,µ(SS) 0-3 b Ye s 20.3 q˜, g˜ 1.35 TeV m(q˜)=m(g˜), cτLS P<1mm 1404.2500 + + 0 0 - χ˜ ± χ0 χ± χ˜1 χ˜1−, χ˜1 Wχ˜1, χ˜ 1 eeν˜µ, eµν˜e 4 e,µ Ye s 20.3 1 750 GeV m( ˜1)>0.2 m( ˜1 ), λ121!0 1405.5086 RPV + +→ 0 0→ χ˜ ± 0 × ± χ˜ χ˜−, χ˜ Wχ˜ , χ˜ ττν˜ , eτν˜ 3 e,µ+ τ - Ye s 20.3 1 450 GeV m(χ˜1)>0.2 m(χ˜1 ), λ133!0 1405.5086 1 1 1 1 1 e τ × g˜ qqq → → 0 6-7 jets - 20.3 g˜ 916 GeV BR(t)=BR(b)=BR(c)=0% ATLAS-CONF-2013-091 → g˜ t˜1t, t˜1 bs 2 e,µ(SS) 0-3 b Ye s 20.3 g˜ 850 GeV 1404.250 → → Scalar gluon pair, sgluon qq¯ 0 4 jets - 4.6 sgluon 100-287 GeV incl. limit from 1110.2693 1210.4826 → Scalar gluon pair, sgluon tt¯ 2 e,µ(SS) 2 b Ye s 14.3 sgluon 350-800 GeV ATLAS-CONF-2013-051 → WIMP interaction (D5, Dirac χ) 0 mono-jet Ye s 1 0 . 5 M* scale 704 GeV m(χ)<80 GeV, limit of<687 GeV for D8 ATLAS-CONF-2012-147 Other √s =7TeV √s =8TeV √s =8TeV 10 1 1 full data partial data full data − Mass scale [TeV] *Only a selection of the available mass limits on new states o rp h e n o m e n ai ss h o w n .A l ll i m i t sq u o t e da rσ eotheoretical b s e r v signal e dm cross i n u section s1 uncertainty.

BNL, 21 June 2016 – p. 13 Searches for new physics, exotics

LQ1(ej) x2 stopped gluino (cloud) LQ1(ej)+LQ1(νj) stopped stop (cloud) LQ2(μj) x2 HSCP gluino (cloud) Long-Lived LQ2(μj)+LQ2(νj) Leptoquarks HSCP stop (cloud) LQ3(νb) x2 q=2/3e HSCP Particles LQ3(τb) x2 q=3e HSCP LQ3(τt) x2 neutralino, ctau=25cm, ECAL time LQ3(vt) x2 0 1 2 3 4 0 1 2 3 4 j+MET, SI DM=100 GeV, Λ RS1(γγ), k=0.1 j+MET, SD DM=100 GeV, Λ RS1(ee,uu), k=0.1 RS Gravitons γ+MET, SI DM=100 GeV, Λ RS1(jj), k=0.1 γ+MET, SD DM=100 GeV, Λ Dark Matter RS1(WW→4j), k=0.1 l+MET, ξ=+1, SI DM=100 GeV, Λ l+MET, ξ=+1, SD DM=100 GeV, Λ 0 1 2 3 4 l+MET, ξ=-1, SI DM=100 GeV, Λ CMS Preliminary l+MET, ξ=-1, SD DM=100 GeV, Λ 0 1 2 3 4 Heavy Gauge SSM Z'(ττ) SSM Z'(jj) Bosons ADD (γγ), nED=4, MS SSM Z'(bb) ADD (ee,μμ), nED=4, MS Large Extra SSM Z'(ee)+Z'(µµ) ADD (j+MET), nED=4, MD Dimensions SSM W'(jj) ADD (γ+MET), nED=4, MD SSM W'(lv) QBH, nED=4, MD=4 TeV SSM W'(WZ→lvll) NR BH, nED=4, MD=4 TeV SSM W'(WZ→4j) Jet Extinction Scale String Scale (jj) 0 1 2 3 4 0 2 4 5 7 9 Excited e* (M=Λ) Compositeness Fermions dijets, Λ+ LL/RR μ* (M=Λ) dijets, Λ- LL/RR q* (qg) dimuons, Λ+ LLIM q* (qγ) dimuons, Λ- LLIM b* dielectrons, Λ+ LLIM 0 1 2 3 4 dimuons, Λ- LLIM coloron(jj) x2 single e, Λ HnCM coloron(4j) x2 Multijet single μ, Λ HnCM gluino(3j) x2 inclusive jets, Λ+ gluino(jjb) x2 Resonances inclusive jets, Λ- 0 1 2 3 4 0 4 8 13 17 21 CMS Exotica Physics Group Summary – ICHEP, 2014

BNL, 21 June 2016 – p. 14 Summary of the LHC ﬁndings

The Standard Model in now complete: the last particle - Higgs boson, predicted by the SM, has been found

BNL, 21 June 2016 – p. 15 Summary of the LHC ﬁndings

The Standard Model in now complete: the last particle - Higgs boson, predicted by the SM, has been found

No signiﬁcant deviations from the SM have been observed (750 ?)

BNL, 21 June 2016 – p. 15 Summary of the LHC ﬁndings

The Standard Model in now complete: the last particle - Higgs boson, predicted by the SM, has been found

No signiﬁcant deviations from the SM have been observed (750 ?)

The masses of the top quark and of the Higgs boson, the Nature has chosen, make the SM a self-consistent effective ﬁeld theory all the way up to the Planck scale

BNL, 21 June 2016 – p. 15 Summary of the LHC ﬁndings

The Standard Model in now complete: the last particle - Higgs boson, predicted by the SM, has been found

No signiﬁcant deviations from the SM have been observed (750 ?)

The masses of the top quark and of the Higgs boson, the Nature has chosen, make the SM a self-consistent effective ﬁeld theory all the way up to the Planck scale End of high energy physics?

BNL, 21 June 2016 – p. 15 Experimental evidence for BSM physics

BNL, 21 June 2016 – p. 16 Experimental evidence for BSM physics

Neutrino masses and oscillations, absent in the Standard Model

BNL, 21 June 2016 – p. 16 Experimental evidence for BSM physics

Neutrino masses and oscillations, absent in the Standard Model

Most of the matter in the universe is dark : no particle physics candidate in the SM

BNL, 21 June 2016 – p. 16 Experimental evidence for BSM physics

Neutrino masses and oscillations, absent in the Standard Model

Most of the matter in the universe is dark : no particle physics candidate in the SM

The Universe is asymmetric: it contains baryons, but there isno antimatter in amounts comparable with matter. This cannot be explained in the SM.

BNL, 21 June 2016 – p. 16 How to reconcile the evidence for new physics without spoiling the success of the Standard Model?

BNL, 21 June 2016 – p. 17 There are hundreds of proposals for models of neutrino masses, for baryogenesis, and for particle dark matter candidates

BNL, 21 June 2016 – p. 18 There are hundreds of proposals for models of neutrino masses, for baryogenesis, and for particle dark matter candidates How to choose?

BNL, 21 June 2016 – p. 18 There are hundreds of proposals for models of neutrino masses, for baryogenesis, and for particle dark matter candidates How to choose? My selection: simplicity

BNL, 21 June 2016 – p. 18 There are hundreds of proposals for models of neutrino masses, for baryogenesis, and for particle dark matter candidates How to choose? My selection: simplicity Ockham’s razor principle (1288 - 1348): “Frustra ﬁt per plura quod potest ﬁeri per pauciora” or ”en- tities must not be multiplied be- yond necessity”.

BNL, 21 June 2016 – p. 18 the νMSM

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BNL, 21 June 2016 – p. 19 The missing piece: sterile neutrinos

Most general renormalizable (see-saw) Lagrangian

M µ I c Lsee−saw = LSM +N¯I i∂µγ NI −FαI L¯αNI Φ− N¯ NI +h.c., 2 I

Assumption: all Yukawa couplings with different leptonic generations are allowed. I ≤ N - number of new particles - HNLs - cannot be ﬁxed by the symmetries of the theory. Let us play with N to see if having some number of HNLs is good for something

BNL, 21 June 2016 – p. 20 N =1: Only one of the active neutrinos gets a mass

BNL, 21 June 2016 – p. 21 N =1: Only one of the active neutrinos gets a mass N =2: Two of the active neutrinos get masses: all neutrino experiments, except LSND-like, can be explained. The theory contains 3 new CP-violating phases: baryon asymmetry of the Universe can be understood item N =2: Two of the active neutrinos get masses: all neutrino experiments, except LSND-like, can be explained. The theory contains 3 new CP-violating phases: baryon asymmetry of the Universe can be understood N =3: All active neutrinos get masses: all neutrino experiments, can be explained (LSND with known tensions). The theory contains 6 new CP-violating phases: baryon asymmetry of the Universe can be understood. If LSND is dropped, dark matter in the Universe can be explained. The quantisation of electric charges follows from the requirement of anomaly cancellations (1-3-3, 1-2-2, 1-1-1, 1-graviton-graviton).

BNL, 21 June 2016 – p. 21 New mass scale and Yukawas

Y 2 = Trace[F †F ]

- - -

BNL, 21 June 2016 – p. 22 N =3with MI

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-".(($%&' (-.")$%&' (")))$*&' ,-"#$*&' ."3,64 -".(($%&' (-.")$%&' (")))$*&' ,-"#$*&' ."3,64 , , -5 -5 -5 9 5 -5 -5 -5 9 5 t t t ' t # t $ t + ' # $ + Left Righ Left Righ Righ Left Righ Left Righ Left Righ Left <0"(),. <0"(),. D).),.6@A)�.B6."3,65 D).),.6@A)�.B6."3,65 +0%7 +0%7 020#(&), '!), (%! 8)� 020#(&), '!), (%! 8)� N = Heavy Neutral Lepton - HNL

Role of N1 with mass in keV region: dark matter

Role of N2,N3 with mass in 100 MeV – GeV region: “give” masses to neutrinos and produce baryon asymmetry of the Universe

BNL, 21 June 2016 – p. 23 What should be the properties of N1,2,3 in the minimal setup - no any type of new physics between the Fermi and Planck scales ? How to search for them experimentally?

BNL, 21 June 2016 – p. 24 DM candidate: the lightest Majorana ν, N1

Yukawa couplings are small → sterile N can be very sta- For one ﬂavour: ble. 1keV 5 10−8 τ 26 sec N N1 =5×10 2 M1 Θ ν ! " # $ Z

mD ν Θ = ν MI

Main decay mode: N → 3ν.

BNL, 21 June 2016 – p. 25 Dark Matter candidate: N1

DM particle is not stable. Main decay mode N1 → 3ν is not observable. Subdominant radiative decay channel: N → νγ. e± ν Photon energy: Ns ν W ∓

M W ∓ γ Eγ = 2

Radiative decay width:

2 9 αEM GF 2 5 Γrad = sin (2θ) M 256 · 4π4 s

BNL, 21 June 2016 – p. 26 Dark Matter production

Cosmological production of sterile neutrinos Sterile neutrino never equilibrates, since their interactions are very weak

2 2 |ΘαI | MI Ω h2 ∼ 0.1 . N −8 α=e,µ,τ 10 1 keV %I % ! "! "

MI 1/3 Production temperature ∼ 130 1keV MeV Production rate depends on Yukawa& couplings' and on lepton asymmetry. Note: DM sterile neutrino does not contribute to the number of relativistic species! Perfect agreement with Planck measurements.

BNL, 21 June 2016 – p. 27 Constraints on DM sterile neutrino N1

Stability. N1 must have a lifetime larger than that of the Universe

Production. N1 are created in the early Universe in reactions l¯l → νN1,qq¯ → νN1 etc. We should get correct DM abundance

Structure formation. If N1 is too light it may have considerable free streaming length and erase ﬂuctuations on small scales. This can be checked by the study of Lyman-α forest spectra of distant quasars and structure of dwarf galaxies

X-rays. N1 decays radiatively, N1 → γν, producing a narrow line which can be detected by X-ray telescopes (such as Chandra or XMM-Newton).

BNL, 21 June 2016 – p. 28 eeto fA ndnie msinLn nteSakdX-r Stacked the in Line Emission Unidentiﬁed An of Detection rne -rn:arXiv:1402.4119 Iaku D. e-Print: Ruchayskiy, Franse. O. , Boyarsky A. galaxy Andromeda cluster. the galaxy Perseus of spectra X-ray in line unidentiﬁed An arXiv:1402. e-Print: Randall. Fo W. A. S. Markevitch, Loewenstein, M. M. Bulbul, Smith, E. Clusters. Galaxy of spectrum

2 Interaction strength [Sin (2θ)] 10 10 10 10 10 10 10 10 10 -14 -13 -12 -11 -10 -9 -8 -7 -6

Phase-space density constraints

Non-resonant production Non-resonant BBN limit: L limit: BBN

Too muchDarkMatter Not enoughDarkMatter

BBN

= 2500 =

L L L

DM mass[keV]

6 6

max

=25 =70

=700

6 =12 5 of darkmatterdecayline Excluded bynon-observation 10 for NRPsterileneutrino Lyman- α bound 2301 50 osy,J. bovskyi, tr .K. R. ster, ay N,2 ue21 .29 p. – 2016 June 21 BNL, and Next step for 3.5 keV line: Astro-H

10 XMM spectrum 9 Resolved spectrum

I Astro-H – new generation X-ray 7 spectrometer with a superb spectral 6 5 resolution 4

Count rate, arb. units 3 I Launched 17 February 2016 2 1

0 I Calibration phase – about 1 year 400 450 500 550 600 650 700 Energy [eV]

I First observational/calibration target – Astro-H SXS Perseus, 1 Msec −3

10 kT = 6.5 keV, 0.6 solar Perseus galaxy cluster, where strong ×

1.5 z=0.0178

) v(baryons) = 300 km/s -1 v(line) = 1300 km/s

3.5 keV line has been detected keV -1 s -2 I Expected to be able to conﬁrm the 3.62 keV −3 Ar XVII DR Ca XIX 10 presence of the 3.5 keV line in Perseus (ph cm Flux Ar XVII Ar XVIII and distinguish it from atomic element 3.55 keV Line

lines (Potassium, Chlorium, etc.) −4 10

× 3 3.2 3.4 3.6 3.8 5 Energy (keV) HOWEVER Status of Astro-H From Supplemental Handout4.1 Presumed on the OperationMechanism(Summary) Plan of the X-ray Astronomy Satellite ASTRO-H (From“Normalsituation”tothe“AttitudeanomalyEvent”,and“Objectsseparation”)

Considering the information above, JAXA concluded that the satellites

functionality(*)UnloadingOperation could to not decrease be the restored momentum and kept in ceased RW within the recovery range of designed activities. range. (April 28) 29 Before its failure Astro-H had started its observational programme

I There are observations of the center of Perseus galaxy cluster

I Observations performed in calibration phase, so low eciency (additional ﬁlters)

I However, the center of Perseus galaxy cluster exhibits one of the strongest signals at 3.5 keV (conﬁrmed by several groups and observed with 3 instruments)

I The data has not been revealed by the collaboration, but based on some conference presentations we expect to see at least a 3 signal

I To summarize: it can still be possible to conﬁrm the presence of the 3.5 keV line in Perseus and distinguish it from atomic element lines (Potassium, Chlorium, etc.) Future after Astro-H failure

Microcalorimeter on sounding rocket (2017)

I Instrument with large ﬁeld-of-view and very high spectral resolution

I Very useful to resolve narrow lines from di↵use sources

I Can improve existing bounds by a factor of few in the mass range (5-15 keV) and partially probe 3.5 keV line region 2 I Fly time 10 seconds pointing to some area in the sky can only explore⇠ a signal from Galactic dark matter halo )

Athena+

I Large ESA X-ray mission (2028)

I X-ray spectrometer (X-IFU) – unprecedented spectral resolution

I Lifetime: 5–10 years

I Very large collecting area (10 that of XMM) ⇥ Baryon asymmetry

Sakharov conditions:

Baryon number violation - OK due co complex vacuum structure in the SM and chiral anomaly

CP-violation - OK due to new complex phases in Yukawa couplings

Deviations from thermal equilibrium - OK as HNL are out of thermal equilibrium for T>O(100) GeV

BNL, 21 June 2016 – p. 30 Baryon asymmetry

Akhmedov, Rubakov, Smirnov; Asaka, MS

Idea - N2,3 HNL oscillations as a source of baryon asymmetry. Qualitatively:

HNL are created in the early universe and oscillate in a coherent way with CP-breaking.

Lepton number from HNL can go to active neutrinos.

The lepton number of active left-handed neutrinos is transferred to baryons due to equilibrium sphaleron processes.

BNL, 21 June 2016 – p. 31 Constraints on BAU HNL N2,3

Baryon asymmetry generation: CP-violation in neutrino sector+singlet fermion oscillations+sphalerons

BAU generation requires out of equilibrium: mixing angle of N2,3 to active neutrinos cannot be too large

Neutrino masses. Mixing angle of N2,3 to active neutrinos cannot be too small

BBN. Decays of N2,3 must not spoil Big Bang Nucleosynthesis

Experiment. N2,3 have not been seen

BNL, 21 June 2016 – p. 32 NuTeV CHARM

! ! 10 6 NuTeV 10 6 CHARM PS191 PS191 BAU BBN BAU

2 !8 2 !8 BBN U U 10 10 BAU BAU

10!10 10!10 Seesaw Seesaw

10!12 10!12 0.2 0.5 1.0 2.0 5.0 10.0 0.2 0.5 1.0 2.0 5.0 10.0 M !GeV" M !GeV"

Constraints on U 2 coming from the baryon asymmetry of the Universe, from the see-saw formula, from the big bang nucleosynthesis and experimental searches. Left panel - normal hierarchy, rightpanel- inverted hierarchy (Canetti, Drewes, Frossard, MS).

BNL, 21 June 2016 – p. 33 Experimental search for HNL

Production via intermediate (hadronic) state p + target → mesons + ...,andthenhadron→ N + .... via Z-boson decays: e+e− → Z → νN

Detection Subsequent decay of N to SM particles

BNL, 21 June 2016 – p. 34 Survey of constraints

BNL, 21 June 2016 – p. 35 How to improve the bounds or to discover light very weakly interacting HNL’s?

BNL, 21 June 2016 – p. 36 Dedicated experiments

Common features of all relatively light feebly interacting particles : Can be produced in decays of different mesons (π,K, charm, beauty) Can decay to SM particles (l+l−, γγ,lπ,etc) Can be long lived Requirements to experiment: Produce as many mesons as you can Study their decays for a missing energy signal: charm or B-factories, NA62, BNL E949 Search for decays of hidden sector particles - ﬁxed target experiments Have as many pot as you can, with the energy enough to produce charmed (or beauty) mesons Put the detector as close to the target as possible, in order tocatchallhidden particles from meson decays (to evade 1/R2 dilution of the ﬂux) Have the detector as large as possible to increase the probability of hidden particle decay inside the detector Have the detector as empty as possible to decrease neutrino and other backgrounds BNL, 21 June 2016 – p. 37 Most recent dedicated experiment - 1986, Vannucci et al

No new particles are found with mass below K-meson, the best for many years constraints are derived, improved by BNL E949 in 2014

BNL, 21 June 2016 – p. 38 Proposal to Search for Heavy Neutral Leptons at the SPS arXiv:1310.1762

W. Bonivento, A. Boyarsky, H. Dijkstra, U. Egede, M. Ferro-Luzzi, B. Goddard, A. Golutvin, D. Gorbunov, R. Jacobsson, J. Panman, M. Patel, O. Ruchayskiy, T. Ruf, N. Serra, M. Shaposhnikov, D. Treille ⇓ General beam dump facility: Search for Hidden Particles

BNL, 21 June 2016 – p. 39 Hidden sector: very weakly interacting relatively light particles: HNL, dark photon, scalars, ALPS, etc

BNL, 21 June 2016 – p. 40 SHiP is currently a collaboration of 46 institutes from 15 countries web-site: http://ship.web.cern.ch/ship/

BNL, 21 June 2016 – p. 41 SHiP schedule

BNL, 21 June 2016 – p. 42 FCC-ee Z-factory

Processes: Z → Nν,N→ lqq¯ (lepton + meson, lepton + 2 quark jets), 2 5 2 GF M 2 BR(Z → νN) ≃ BR(Z → νν)U , ΓN ≃ U A 192π3

Coefﬁcient A counts the number of open channels, A ∼ 10 for M>10 GeV Detector of size L:

“short lived” N: decay length < L =⇒ constraint on U 2 may go down to U 2 < 10−10 as the sensitivity will grow as the number of Z-decays! This works for M ! 20 GeV.

“long lived” N: decay length exceeds the size of the detector =⇒ constraint on U 2 may go down to U 2 < 4 × 10−8 as the sensitivity will grow as the square root of the number of Z-decays. This works for lighter HNL. BNL, 21 June 2016 – p. 43 SHiP and FCC-ee sensitivity

Normal hierarchy Normal hierarchy Normal hierarchy 10-6 10-6 10-6 NuTeV NuTeV NuTeV

-7 -7 -7 10 PS191 10 PS191 10 PS191

BAU BAU BAU 10-8 10-8 10-8

2 SHiP 2 SHiP 2 SHiP -9 -9 -9 |U| |U| |U| 10 10 10

10-10 BBN FCC-ee 10-10 BBN FCC-ee 10-10 BBN FCC-ee 10-11 10-11 10-11 Seesaw Seesaw Seesaw

1 10 1 10 1 10 HNL mass (GeV) HNL mass (GeV) HNL mass (GeV)

Inverted hierarchy Inverted hierarchy Inverted hierarchy 10-6 10-6 -6 NuTeV NuTeV 10 NuTeV CHARM CHARM CHARM -7 -7 10 10 10-7 PS191 PS191 PS191 BAU BAU BAU -8 -8 10 10 10-8 2 2 SHiP SHiP 2 SHiP -9 -9 -9

|U| 10 |U| 10

|U| 10

-10 -10 10 BBN FCC-ee 10 BBN FCC-ee 10-10 BBN FCC-ee -11 -11 10 Seesaw 10 Seesaw 10-11 Seesaw

1 10 1 10 1 10 HNL mass (GeV) HNL mass (GeV) HNL mass (GeV) Decay length: 10-100 cm 10-100 cm 0.01-500 cm

1012 Z0 1013 Z0 1013 Z0

BNL, 21 June 2016 – p. 44 Conclusions

Heavy neutral leptons can be a key to (almost all) BSM problems: neutrino masses and oscillations dark matter baryon asymmetry of the universe

They can be found in Space and on the Earth X-ray satellites proton ﬁxed target experiment - SHiP, M " 2 GeV collider experiments at FCC-ee in Z-peak, M ! 2 GeV

BNL, 21 June 2016 – p. 45