Testing the low scale seesaw and leptogenesis

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1 based on and with Marco Drewes, Björn Garbrecht and Juraj Klarić Bielefeld, 18. May 2017

2 Remaining puzzles of the universe BAU baryon asymmetry of the universe WMAP, Planck and Big bang nucleosynthesis: Neutrino masses Nobel prize 2015 Kajita, McDonald n B /n γ = 6.05(7) 10 10

3 Remaining puzzles of the universe BAU baryon asymmetry of the universe WMAP, Planck and Big bang nucleosynthesis: Neutrino masses Nobel prize 2015 Kajita, McDonald n B /n γ = 6.05(7) SM is not enough

4 Remaining puzzles of the universe BAU baryon asymmetry of the universe WMAP, Planck and Big bang nucleosynthesis: Neutrino masses Nobel prize 2015 Kajita, McDonald n B /n γ = 6.05(7) SM is not enough Need to go beyond the SM

5 Extending the Standard Model by RH neutrinos quarks leptons 2.3 MeV u up 4.8 MeV down d 511 kev e electron ν e I II III < 2 ev 1.28 GeV c charm 95 MeV s strange µ MeV muon < 190 kev ν µ GeV t top 4.7 GeV b bottom GeV τ tau < 18.2 MeV ν τ g gluon γ photon 91.2 GeV Z 80.4 GeV W ± GeV H Higgs e neutrino µ neutrino τ neutrino

6 Extending the Standard Model by RH neutrinos quarks leptons I II III 2.3 MeV u up 4.8 MeV down d 511 kev e electron < 2 ev ν e N GeV c charm 95 MeV s strange µ MeV muon < 190 kev ν µ N GeV t top 4.7 GeV b bottom GeV τ tau < 18.2 MeV ν τ N 3 g gluon γ photon 91.2 GeV Z 80.4 GeV W ± GeV H Higgs e neutrino µ neutrino τ neutrino

7 RH neutrinos could solve these puzzles BAU baryon asymmetry of the universe WMAP, Planck and Big bang nucleosynthesis: Neutrino masses Nobel prize 2015 Kajita, McDonald n B /n γ = 6.05(7) LEPTOGENESIS SEE-SAW MECHANISM m ν = v 2 Y M 1 M Y

8 Neutrino masses via seesaw mechanism Add RH neutrinos (SM singlets) ν R to SM L l L Y ν R Φ 1 2 νc R M Mν R + h.c. Two sets of Majorana mass states after EW symmetry breaking ν U ν (ν L + θν c R ) light neutrinos mostly active doublet light masses: m ν v 2 Y M 1 M Y N ν R + θ T ν c L heavy neutrinos mostly sterile singlets heavy masses: M N M M m ν N only interact via small mixing U 2 ai θ ai 2 1

9 Constraints on RHN parameters Direct constraints - past experiments Seesaw constraints - neutrino oscillation data Cosmological constraints - BBN τ N < 0.1 s Indirect constraints neutrinoless double β decay lepton universality CKM universality electroweak precision data rare lepton decays

10 Direct constraints [Plot from arxiv: ]

11 Seesaw constraints 10-5 U seesaw M [GeV]

12 Constraints on flavour patterns: Normal hierarchy Uμ 2 /U sin 2 θ 23 = sin 2 θ 23 = δ = Ue 2 /U 2

13 Constraints on flavour patterns: Inverted hierarchy Uμ 2 /U sin 2 θ 23 = sin 2 θ 23 = 0.45 δ = Ue 2 /U 2

14 Cosmological constraints - BBN 10-5 U BBN seesaw M [GeV]

15 Global constraints - Inverted neutrino mass hierarchy Uμ global constraints M [GeV]

16 Global constraints - Inverted neutrino mass hierarchy 10-4 Uμ LEPTOGENESIS? global constraints M [GeV]

17 Evolution Equations RHN density matrix dn dz = i 2 [H, n] 1 2 {Γ, n neq } Γq l Active lepton equations dq l dz = S l(n) W q l + T W q N Density matrix of the RHN( ) n11 n n = 12 n 21 n 22 Effective Hamiltonian H of the RHN M 2 Production rate Γ Y 2 Source term S l of the active neutrinos Washout term W

18 Oscillatory regime small mixing angles SM Thermal Bath CP - even RHN CP - odd RHN Lepton Number Asymmetry Re[n12 odd ]/s Δa/s Baryon Number Asymmetry YB z=t EW /T

19 Overdamped regime large mixing angles SM Thermal Bath CP - even RHN CP - odd RHN Lepton Number Asymmetry Re[n12 odd ]/s Δa/s Baryon Number Asymmetry YB z=t EW /T

20 LBNE Results: Inverted hierarchy 10-5 BAU (upper bound) 10-7 ILC CEPC U SHiP FCC-ee(Z) BAU (lower bound) disfavoured by global constraints M [GeV] [Drewes/Garbrecht/Gueter/Klarić ]

21 Results: Inverted hierarchy 10-5 BAU (upper bound) FCC-ee(B) Belle II FCC-ee(W) LHC 10-7 NA62 U μ T2K SHiP disfavoured by global constraints BAU (lower bound) M [GeV] [Drewes/Garbrecht/Gueter/Klarić ]

22 Flavour patterns from leptogenesis: Normal hierarchy M = 1 GeV 0.8 U Uμ 2 /U Ue 2 /U 2 [Drewes/Garbrecht/Gueter/Klarić ]

23 Flavour patterns from leptogenesis: Inverted hierarchy 0.5 M = 1 GeV U Uμ 2 /U Ue 2 /U 2 [Drewes/Garbrecht/Gueter/Klarić ]

24 Leptogenesis and neutrinoless double β decay m min 0 [Bilenky ]

25 Leptogenesis and neutrinoless double β decay [Eijima/Drewes ]

26 Conclusions GeV scale RHN could simultaneously generate the light neutrino masses via the seesaw mechanism and the BAU via leptogenesis. The requirement to explain both imposes constraints of the RHN masses spectrum, flavour mixing pattern and CP properties. GeV scale neutrinos may be found at the proposed SHiP experiment or a future high-energy collider. A combination of different observables could reconstruct enough fundamental parameters in order to decide if these could in fact be responsible for the BAU.

Marco Drewes, Université catholique de Louvain. The Other Neutrinos IAP Meeting. Université libre de Bruxelles

Marco Drewes, Université catholique de Louvain The Other Neutrinos 21.12.2017 IAP Meeting Université libre de Bruxelles The Standard Model of Particle 125 GeV The periodic table of elementary particles