Neutrinos and the Baryon Asymmetry of the Universe Valerie Domcke DESY Hamburg Neutrino Platform 2018 @ CERN based partly on 1507.06215, 1709.00414 in collaboration with A. Abada, G. Arcadi, and M. Lucente bla The observed baryon asymmetry of the Universe tiny matter-antimatter asymmetry in the early universe as particles and anti-particles annihilate, tiny asymmetry results in matter dominated Universe Sakharov conditions for dynamical generation [Sakharov '67] • violation of B (or L) • violation of C and CP • departure from thermal equilibrium [Particle Data Group] Neutrinos and the Baryon Asymmetry of the Universe| Valerie Domcke | DESY | 01.02.2018 | Page 2 Baryogenesis meets particle physics electroweak baryogenesis thermal leptogenesis (1st order phase EW PT) (NR decay) ARS leptogenesis GUT baryogenesis (NR oscillations) (X decay) Baryogenesis / Leptogenesis SM sphalerons, violate B+L gravitational (SM gravitiational anomaly, RR~) non-thermal leptogenesis (NR decay) Affleck-Dine through magnetogenesis (B L charged scalar) − (helical magnetic fields) and more ... Neutrinos and the Baryon Asymmetry of the Universe| Valerie Domcke | DESY | 01.02.2018 | Page 3 Baryogenesis meets particle physics electroweak baryogenesis thermal leptogenesis (1st order phase EW PT) (NR decay) ARS leptogenesis GUT baryogenesis (NR oscillations) (X decay) Baryogenesis / Leptogenesis SM sphalerons, violate B+L gravitational (SM gravitiational anomaly, RR~) non-thermal leptogenesis (NR decay) Affleck-Dine through magnetogenesis (B L charged scalar) − (helical magnetic fields) and more ... Neutrinos and the Baryon Asymmetry of the Universe| Valerie Domcke | DESY | 01.02.2018 | Page 3 Outline (Standard) thermal leptogenesis • overview • implications for the neutrino sector Leptogenesis through neutrino oscillations (ARS) • overview • neutrino mass models Neutrino observables from ARS • active-sterile mixing • tests at colliders • neutrinoless double beta decay Neutrinos and the Baryon Asymmetry of the Universe| Valerie Domcke | DESY | 01.02.2018 | Page 4 (Standard) thermal leptogenesis [Fukugita,Yanagida '86] right-handed Majorana neutrinos with ∆L = 2 process h h LH ν N N¯ ν H¯ L¯ ! ! ! thermal initial conditions eq ( nN;N¯ 1 for T > MN = 2 3=2 n π mN MN =T γ ζ(3) 2πT e− for T < MN if ΓN . H T =MN , abundance cannot track rapidly falling thermal abundancej departure from thermal equilibrium: ! 2 Γ H (hy h )M M =M N . jT =MN ! ν ν N . N P CP violation in N-decays n =s TRH=M ! ∆L ∼ N conversion to baryon asymmetry through sphaleron processes Neutrinos and the Baryon Asymmetry of the Universe| Valerie Domcke | DESY | 01.02.2018 | Page 5 (Standard) thermal leptogenesis The two key parameters of thermal leptogenesis are closely tied to neutrino physics: CP 2 ¨ ΓN LH ΓN L¯H¯ (hνy hν )v ¨CP : = ! − ! wash-out : m CP e 1 M ΓN LH + ΓN L¯H¯ ∼ N ! ! Type - I seesaw mechanism: 1 T 1 2 mν MN m = (h M − h )v m ; 0:1 ν 2 ν N ν ∼ e 1 . v2 8 lower bound: TRH > MN > 10 GeV [Davidson,Ibarra '02] A! typical example ( GUT scale leptogenesis): ∼ 13 3 M 10 GeV ; m~ 0:01 eV ; h 0:1 ; 10− N ∼ 1 ∼ ν ∼ ∼ Neutrino mass generation + cosmic history viable high-scale leptogenesis mechanism ! Neutrinos and the Baryon Asymmetry of the Universe| Valerie Domcke | DESY | 01.02.2018 | Page 6 (Standard) thermal leptogenesis [Buchm¨uller,Di Bari, Pl¨umacher '04] thermal initial conditions vanishing initial conditions Beautiful - but very hard to test! Neutrinos and the Baryon Asymmetry of the Universe| Valerie Domcke | DESY | 01.02.2018 | Page 7 Outline (Standard) thermal leptogenesis • (overview • (implications for the neutrino sector Leptogenesis through neutrino oscillations (ARS) • overview • neutrino mass models Neutrino observables from ARS • active-sterile mixing • tests at colliders • neutrinoless double beta decay Neutrinos and the Baryon Asymmetry of the Universe| Valerie Domcke | DESY | 01.02.2018 | Page 8 defining a generalized lepton number under which also the Ns are charged, both the active and sterile sectorL develop a ∆ of equal magnitude but opposite sign (for M T ) L N Sphaleron processes only pick up the ∆ = ∆L of the active sector, leading to a net baryon asymmetry L low-scale leptogenesis mechanism experimentally accessible ! ! Leptogenesis through neutrino oscillations [Akhmedov, Rubakov, Smirnov '98] nearly degenerate right-handed Majorana neutrinos N with MN 7 2 ∼ MeV - GeV and weak coupling to SM, h 10− ± ν ∼ starting from a vanishing initial abundance, Ns are thermally produced but do not reach full thermal equilibrium before the EW phase transition (= sphaleron freeze-out) NR oscillations create a CP violating background for the active neutrinos Neutrinos and the Baryon Asymmetry of the Universe| Valerie Domcke | DESY | 01.02.2018 | Page 9 Leptogenesis through neutrino oscillations [Akhmedov, Rubakov, Smirnov '98] nearly degenerate right-handed Majorana neutrinos N with MN 7 2 ∼ MeV - GeV and weak coupling to SM, h 10− ± ν ∼ starting from a vanishing initial abundance, Ns are thermally produced but do not reach full thermal equilibrium before the EW phase transition (= sphaleron freeze-out) NR oscillations create a CP violating background for the active neutrinos defining a generalized lepton number under which also the Ns are charged, both the active and sterile sectorL develop a ∆ of equal magnitude but opposite sign (for M T ) L N Sphaleron processes only pick up the ∆ = ∆L of the active sector, leading to a net baryon asymmetry L low-scale leptogenesis mechanism experimentally accessible ! ! Neutrinos and the Baryon Asymmetry of the Universe| Valerie Domcke | DESY | 01.02.2018 | Page 9 Boltzmann equations Kinetic equations for neutrino density matrix ρ ; A; B N; N;¯ ν; ν¯ AB 2 f g dρ i i i = [H; ρ] Γ; ρ + Γp;I ρ [Sigl, Raffelt '93] dt − 2 f g 2 f − g Assuming MN mν : active-sterile oscillations suppressed, eq kinetic equilibrium: ρNN (T; k) = RN (T )ρNN (T; k), thermal equilibrium for active ν: ρ ρeq(T; k) exp [ diag(µ )]: ν;ν¯ ∼ ± Lα dRN 1 (0) 1 (1b) = i [ H ;R ] γ F yF; R I γ F yµ F; R dt − h i N − 2h i N − − 2h i L N (1a) + γ F yµ F; h i L dµ∆α 9 ζ(3) n (0) T (1a) = 2 γ FRN F y F ∗RN¯ F 2 γ µLFF y+ dt − 2ND π h i − − h i (1b) T o + γ µL FRN F y + F ∗RN¯ F ; [Asaka, Shaposhnikov '05] h i αα w. F = Yukawa coupling in mass basis, H = eff. Hamiltonian, h·i = thermal average Neutrinos and the Baryon Asymmetry of the Universe| Valerie Domcke | DESY | 01.02.2018 | Page 10 Benchmark solutions [Abada, Arcadi, VD, Lucente '15, '17] 7 weak washout regime, F 10− (analytical solutions available) j j . 6 intermediate/strong washout regime, F 10− (perturbative expansion) j j ∼ Neutrinos and the Baryon Asymmetry of the Universe| Valerie Domcke | DESY | 01.02.2018 | Page 11 Neutrino mass models for ARS leptogenesis Inverse Seesaw [Wyler, Wolfenstein '83; Mohapatra, Valle '86] (schematically for `active', `RH', `sterile') 0 0 1 h v 01 0 1 p2 ν 0 0 0 M = 1 h v 0 Λ + ξ 0 0 0 ν @ p2 ν A @ A 0 Λ 0 0 0 Λ | {z } | {z } L conserving ∆L=2 ξ(h v)2 m ν ; ∆m2 = M 2 M 2 2ξΛ2 ) ν ' 2Λ N2 − N1 ' Linear Seesaw [Barr '04; Malinsky, Romao, Valle '05] 0 0 1 h v 01 0 0 0 1 h v1 p2 ν p2 ν0 M = 1 h v 0 Λ + 0 0 0 ν @ p2 ν A @ A 1 h v 0 0 0 Λ 0 p2 ν0 | {z } | {z } L conserving ∆L=2 (h v)2 m ν ; ∆m2 = M 2 M 2 2(h v)2 ) ν ' Λ N2 − N1 ' ν Neutrinos and the Baryon Asymmetry of the Universe| Valerie Domcke | DESY | 01.02.2018 | Page 12 Neutrino mass models for ARS leptogenesis Inverse Seesaw [Wyler, Wolfenstein '83; Mohapatra, Valle '86] (schematically for `active', `RH', `sterile') 0 0 1 h v 01 0 1 p2 ν 0 0 0 M = 1 h v 0 Λ + ξ 0 0 0 ν @ p2 ν A @ A 0 Λ 0 0 0 Λ | {z } | {z } L conserving ∆L=2 ξ(h v)2 m ν ; ∆m2 = M 2 M 2 2ξΛ2 ) ν ' 2Λ N2 − N1 ' Linear Seesaw [Barr '04; Malinsky, Romao, Valle '05] plus Inverse Seesaw 1 0 1 1 0 0 h v 01 0 0 h0 v p2 ν p2 ν M = 1 h v 0 Λ + B 0 0 0 C ν @ p2 ν A @ A 1 h v 0 ξ Λ 0 Λ 0 p2 ν0 | {z } | {z } L conserving ∆L=2 (h v)2 m ν ; ∆m2 = M 2 M 2 2(h v)2 ) ν ' Λ N2 − N1 ' ν Neutrinos and the Baryon Asymmetry of the Universe| Valerie Domcke | DESY | 01.02.2018 | Page 12 Strategy [Abada, Arcadi, VD, Lucente '15,'17] Generate data points which respect all constraints on active neutrino masses/mixings as well as laboratory constraints on sterile neutrinos minimial models: LISS(1,1), ISS(2,2), ISS(2,3) [Abada, Lucente '14] ) Calculate baryon asymmetry by solving Boltzmann equations • analytically in the weak washout regime • perturbative numerical procedure otherwise requirements for successful leptogenesis: constraints) on masses, Yukawa couplings, mixing angles... Neutrinos and the Baryon Asymmetry of the Universe| Valerie Domcke | DESY | 01.02.2018 | Page 13 Neutrino mass models for ARS leptogenesis weak washout regime, LISS model (2 additional NR's): intermediate/strong washout regime: LISS ISS(2,2) Neutrinos and the Baryon Asymmetry of the Universe| Valerie Domcke | DESY | 01.02.2018 | Page 14 Why consider specific mass models? fewer parameters / more predictive small parameters are symmetry protected directions for further model building ! distinguish model independent from model-dependent features but do not cover entire ARS parameter space Neutrinos and the Baryon Asymmetry of the Universe| Valerie Domcke | DESY | 01.02.2018 | Page 15 An example: dark matter in the ISS(2,3) MPD decouple mPD GeV leptogenesis ∆m keV ∼ keV mDM dark matter (Dodelson-Widrow) eV mν ν oscillations with 5 1=2 1=2 mDM ∆m 3 10− mPD mν 10− mPD ' mPD ' F GeV 0:05 eV j j Neutrinos and the Baryon Asymmetry of the Universe| Valerie Domcke | DESY | 01.02.2018 | Page 16 An example: