Neutrino theory of everything? dark matter, baryogenesis and neutrino masses 25 th International Workshop on Weak Interactions and Neutrinos (WIN2015) June 8-13, 2015, MPIK Heidelberg, Germany @Heidelberg ()
Overview Neutrino Masses How to test? 2 Right-handed Neutrinos Dark Matter Baryon Asymmetry of the Universe
3 Neutrino Masses ー Seesaw Mechanism
RH Neutrinos and Seesaw Mechanism 4 M M c L i R R F L R R R 2 + h.c. Minkowski ʼ77 Yanagida ʼ79 Gell-Mann, Ramond, Slansky ʻ79 Glashow ʻ79 Seesaw mechanism ( Φ ) c c 1 0 0 c MD L 1 c M L ( L, R) hc. (, N ) hc.. T 2 M D M M 2 0 M T 1 R M N M MD MD M M T U M U diag( m1, m2, m3) Light active neutrinos explain neutrino oscillations Heavy neutral leptons Mass Mixing Θ / mixing in CC current
Yukawa Coupling and Mass of HNL 5 F 10 2 10 1 10 0 10-1 10-2 10-3 10-4 10-5 10-6 10-7 10-8 10-9 10-10 10-11 10-12 10-13 10-14 Seesaw does not work! 10-10 10-5 10 0 10 5 10 10 10 15 10 20 M N [GeV] Φ 5 10 GeV
Yukawa Coupling and Mass of HNL 6 F 10 2 10 1 10 0 10-1 10-2 10-3 10-4 10-5 10-6 10-7 10-8 10-9 10-10 10-11 10-12 10-13 10-14 Seesaw does not work! 10-10 10-5 10 0 10 5 10 10 10 15 10 20 M N [GeV] Φ Leptogenesis (Fukugita, Yanagida ʻ86) Baryogenesis via neutrino oscillation (Akhmedov, Rubakov, Smirnov ʼ98, TA, Shaposhnikov ʼ05, ) 5 10 GeV
Mixing and Mass of HNL 7 10 0 Θ 5 10 GeV 10-5 Baryogenesis via neutrino oscillation 10-10 Θ 2 10-15 10-20 Leptogenesis 10-25 10-30 10-10 10-5 10 0 10 5 10 10 10 15 10 20 M N [GeV]
Various Physics of HNLs 8 10 0 10-5 Baryogenesis via neutrino oscillation Θ 2 10-10 10-15 10-20 Dark Matter 10-25 10-30 10-10 10-5 10 0 10 5 10 10 10 15 10 20 M N [GeV]
Various Physics of HNLs 9 MSM TA, Blanchet, Shaposhnikov ʻ05, TA, Shaposhnikov ʻ05 10 0 10-5 Baryogenesis via neutrino oscillation 10-10, Θ 2 10-15 10-20 Dark Matter 10-25 10-30 10-10 10-5 10 0 10 5 10 10 10 15 10 20 M N [GeV]
10 Dark Matter ー HNL with ~kev
Properties of DM N1 11 TA, Laine, Shaposhnikov ʻ07
Mixing for DM abundance DM abundance Ω Ω 0.1 12 TA, Laine, Shaposhnikov ʻ07 sin 2 8 10 1keV DM is produced by scatterings Dodelson, Widrow ʻ94 W,Z N1
Cosmological constraint (1) 13 Radiative decays of DM Dominant decay: 3 Subdominant decay TA, Laine, Shaposhnikov ʻ07 Severely restricted from X-ray observations Upper bound on mixing angle!
Cosmological constraint (2) DM plays as WDM and may erase structures on small scales! 14 TA, Laine, Shaposhnikov ʻ07 ~Mpc kev Lower bound on mass Ly- forest observations 8 kev(dw scenario) Boyarsky, Lesgourgues, Ruchayskiy, Viel ʼ09, ʼ09 The simplest Dodelson-Widrow scenario conflicts with cosmological constraints
Current status Other production mechanism is needed!! Laine, Shaposhnikov ʻ08 15 Shi-Fuller mechanism with large lepton asymmetry Shi, Fuller ʼ99 Scenario in the numsm Canetti, Drewes, Shaposhnikov ʼ13 Canetti, Drewes, Frossard, Shaposhnikov ʻ13 Additional interactions of DM (scalar, Zʼ, ) Shaposhnikov, Tkachev ʻ06, Kusenko ʻ06, Petraki, Kusenko ʻ06 Bezrukov, Gorbunov ʼ10, Bezrukov, Kartavtsev, Lindner ʻ12, Tsuyuki ʼ14,
X-rays from DM decays? 16 Unidentified x-ray line with E 3.5keV Bulbul et al (arxiv:1402.2301) Boyarsky, Ruchayskiy, Iakubovskyi, Franse (arxiv:1402.4119) Can be explained by DM 7keV sin 2Θ 10
17 Baryon Asymmetry ー Baryogenesis via Neutrino Oscillation
Baryon asymmetry of the universe (BAU) 18 Baryon Number = (# of baryons) (# of antibaryons) Planck 2015 [arxiv:1502.01589] n B s : : Baryon number density Entropy density Condiations for baryogenesis: Sakharov (1967) (1) Baryon number B is violated (2) C and CP symmetries are violated (3) Out of thermal equilibrium
Baryogenesis in the MSM 19 B and L violations B violation due to EW sphaleron for L violation due to Majorana masses Since,, this violating effect is negligible for baryogenesis temperature C and CP violations 1 CP phase in quark sector 6 CP phases in lepton sector Among them 3 CP phases associated with, are relevant Out of equilibrium No 1st order EW phase transition as in the SM, can be out of equilibrium for, if Yukawa couplings are small enough
Baryogenesis via Neutrino Oscillation 20 Oscillation of HNLs can be a source of BAU Akhmedov, Rubakov, Smirnov (ʼ98) / TA, Shaposhnikov (ʻ05) Shaposhnikov (ʼ08), Canetti, Shaposhnikov (ʻ10) TA, Ishida (ʻ10), Canetti, Drewes, Shaposhnikov (ʼ12), TA, Eijima, Ishida (ʻ12) Canetti, Drewes, Shaposhnikov (ʻ12), Canetti, Drewes, Frossard, Shaposhnikov (ʻ12) Oscillation starts at ~ / Medium effects 8 N L N Asymmetries are generated since evolution rates of and are different due to CPV
Key points 21 Baryogenesis via leptogenesis B L sphaleron B L Baryogenesis via neutrino osc. B L B L sphaleron
Baryogenesis Region 22 Region accounting for IH NH Canetti, Shaposhnikov ʻ10 8.55-9.00) 10 ΔΜ [ev] 10 7 Two RH neutrino case 10 6 10 5 10 4 IH 10 3 NH 10 2 10 1 10 0 10-1 10-2 10-3 10-4 10-4 10-3 10-2 10-1 10 0 M N [GeV] TA, Eijima ʻ13
Allowed regions for HNLs N2 and N3 23 Allowed region of HNLs N2 and N3 for the seesaw mechanism and baryogenesis via neutrino oscillation Blondel Graverini, Serra, Shaposhnikov (arxiv:1411.5230)
24 Experimental Tests for Heavy Neutral Leptons
Search at SHiP 25 SHiP is a fixed-target experiment at CERN SPS NHLs are produced in charmed meson decays look for a visible decay of HNLs (,, ) inside detector Technical Proposal arxiv:1504.04956
Search at FCC-ee (TLEP) 26 Future Circular Collider at CERN includes collisions as a possible first step toward 100 TeV pp collider. At Z-pole, 10-10 Z bosons HNLs are produced in Z boson decays ( ) look for a displaced vertex of HNL decay Blondel Graverini, Serra, Shaposhnikov (arxiv:1411.5230)
Search at T2K 27 HNLs are produced in kaon decays as active neutrinos look for a visible decay of HNLs inside ND280 PS191 T2K T2K at 10 POT has a better sensitivity than PS191 (0.86 10 POT)! TA, Eijima, Watanabe ʻ13
Test by Lepton Universality Shrock 1981 28 HNLs may modify lepton universality in kaon decays Γ Γ Δ TA, Eijima, Takeda ʻ14 Δ 10 will be probed by near future experiments NA62@CERN and TREK/E36@J-PARC!
Summary 29 The MSM is SM with three RH neutrinos with Lightest Heavy Neutral Lepton Dark Matter with kev Heavier Heavy Neutral Leptons Quasi-degenerate with ~100MeV-100GeV Seesaw mass matrix for masses and mixings of active neutrinos Baryon Asymmetry of the Universe (BAU) through the mechanism via neutrino oscillation N 1 N and N 2 3 Heavy neutral leptons in the MSM can be tested experimentally Tests of HNLs are crucial to identify the origin of neutrino masses, but also to reveal the mysteries of our universe (DM, BAU, )!!!