Baryon-Dark Matter Coincidence Bhaskar Dutta Texas A&M University Based on work in Collaboration with Rouzbeh Allahverdi and Kuver Sinha Phys.Rev. D83 (2011) 083502, Phys.Rev. D82 (2010) 035004 Miami 2011 1
Coincidence Problem n s DM 510 m DM 10 : Dark matter abundance of the Universe [CMB] entropy density n b n s b 910 11 : Baryon asymmetry of the Universe [CMB & BBN] W c, W DM ~ 6 W B? What is the source of this coincidence? Both redshift in the same way This coincidence may be a particle physics model property 2
Early Universe Production of DM: Thermal Models: Hubble expansion dominates over the m interaction rate: freeze out Dark Matter content: W DM ~ 1 v v 310 26 Non Thermal Models: Late Decay (T r ) of some fields produce the DM particles, T r <T f We need larger cross-section : T f / T r < v> T f cm 3 s ~ DM Typical Dark Matter candidates: neutralino, sneutrino etc Which scenario is correct? Which dark matter particle? LHC may give us clue 20
Early Universe Generation of Baryon asymmetry: Requirements (Sakharov Condition) B violation, C and CP violation; Out of equilibrium decay Without violating both, B-violating processes would make just as many baryons as antibaryons Possible scenarios: EW Baryogenesis, GUT Baryogenesis, Leptogenesis etc In general baryon asymmetry physics is not correlated to that of DM Can the baryon and the dark matter contents be correlated? 4
Coincidence Problem-Models A few ideas Asymmetric Dark Matter Generate baryon or lepton asymmetry Transfer lepton or baryon asymmetry to Dark Matter E.g., W = LHX 2 /M, W = uddx 2 /M 2 n X n n X l, B nl, B Symmetric component [X X] annihilates, asymmetric part determines the relic density Cross-section is large Since the same asymmetry is responsible, matter density favors light dark matter 5-10 GeV S. Barr (1992), D. B. Kaplan (1993) [Early papers] Variants of asymmetric dark matter: Sneutrino Dark Matter, Hylogenesis, Aidnogenesis, Darkogenesis etc An, Agashe, Belayev, Blennow, Buckley, Cirelli, Davoudiasl, Dasgupta, Dutta, Fernandez-Martinez, Gu, Hall, Hooper, Kaplan, Kitano, Kumar, Low, Luty, March- Russell, Morrisey, Randall, Pierce, Sarkar, Servant, Thomas, West, Zhang, Zurek 5
Coincidence Problem-Models Typical issues: The symmetric part of DM needs to completely annihilate The annihilation cross-section depends on mass and couplings and is not related to baryons The natural prediction is n DM ~ O(n B ) m DM is O(GeV) to satisfy the coincidence problem 6
Coincidence Problem: Cladogenesis Possible connection: Both DM abundance and Baryon asymmetry are produced from the same source Moduli decay: Source of Baryon asymmetry and DM Phys.Rev. D83 (2011) 083502 Cladogenesis: is an evolutionary splitting event in a species in which each branch and its smaller branches forms a "clade", an evolutionary mechanism and a process of adaptive evolution that leads to the development of a greater variety of sister species. 7
The moduli decay width: Cladogenesis Moduli are heavy scalar fields that acquire mass after SUSY breaking and are gravitationally coupled to matter 3 c m 2 2 M p Inflation Radiation domination start oscillating when H < m dominate the Universe before decaying and reheating it T r ~ c 1/ 2 m 100TeV 3/ 2 (5MeV) T r ~ MeV for m ~100 TeV: not allowed by BBN moduli domination radiation domination... 8
Cladogenesis Moduli decay produces dilution in the yield of the decay products The dilution factor even from a 100 TeV moduli is huge! Y n s 3 1/ 2 1/ 2 8 Tr 4m ~ c m 100TeV (510 ) Any previously produced DM abundance and baryon asymmetry is also diluted away 9
Cladogenesis Two Possibilities: 1. Baryon asymmetry and DM abundance are produced before the moduli decay Very hard for DM Becomes impossible if this modulus is an inflaton 2. Baryon asymmetry and DM abundance are produced from the moduli decay Post-sphaleron Baryogenesis & non-thermal DM 10
Cladogenesis Large Dilution Factor Almost saturates the need for DM and Baryon abundance ~ 10-10 10 or so [Since n 510 ] [Easy for a different cut off scale/modification of c : T r <<T EW, T f 1/3 T r M 5MeV Ref: Large Volume Scenario: Cicoli, Mazumdar, 2010] Typical mass of this moduli field : 100 TeV <m <1000 TeV It is natural to expect : m ~ O(10) x gravitino mass Y ~ 2/3 p 8 Type IIB moduli stabilization: Adams etal 2011 c DM s 2/3 m DM (510 ) 11
Cladogenesis We consider the Mirage Mediation Model [Choi, Falkowski, Nilles, Olechowski, Pokorski; Choi, Jeong, Okumura] Clear predictions for the LHC The possible range for dilution: Y ~ 10 7 10 9 12
Cladogenesis Baryon Asymmetry in this model: Br N : branching ratio of moduli decay to N : asymmetry factor in the N decay b b Y BrN 9 7 Y ~10 10, <0.1, Br N ~ 10-2 -1 B = 9x10-11 All particles in the observable sector are produced from the modulus decay: dilution factor, branching ratio source for baryon asymmetry (e.g., via N particles interaction) and DM are same B n s n Assuming that N produces Baryon Asymmetry due to nos. of degrees of freedom 13
Cladogenesis DM in this model is the lightest SUSY particles DM abundance in this model: n s Y Y ~ 10 Br 7 10 9 Br : branching ratio of moduli decay to We use: min. Y Br, 8 45 2 g * M p 1 T r v Moroi, Randall 99 If this is smaller, not enough dark matter particles are produced to start the self annihilation Upper bond on <v> easy to satisfy in models Br 10 3 Lower limit from the branching ratio into gauginos Wb 1 BRN Using Leads to 5GeV m 500GeV W m BR 14
Cladogenesis Br 10 3 arises due to 3-body decay of moduli into gauginos via gauge boson pair production: g gg ~ ~ vs g ~ g ~ It is possible to have 3 body decay width larger than the 2-body decay width of moduli into gauginos We need suppression of two-body decays to R-parity odd particles The dominant decay mode to gauge boson final states L C 2 (Re K f ) 1 (~ T gg i 1 4 F 2 N F : KKLT ) 1 4M m 3 g 1 2 Ti C 2 i 2 128 M P p 1 C F F 15
Cladogenesis 1 L 4M ( F e p ( ( D W ) K K / 2 N Gauginos g 2 T gg ~~ C p 128 F C m i 2 Ti pf i 2 p M P Decay to gauginos needs to be suppressed Can be satisfied in multiple moduli scenario ) h. c.) Requirements: C i ~ 1, p( p) C p( p) ( m p( p) T i F T i ) ~ 0.1 0.01, Leads to suppression of two-body decays to R-parity odd particles: 16
Cladogenesis L 1 G / 2 2 e ( G G )[ m mn n m mn ] n G K 2 Log W 2 3 ~ Ti Ti T T T 2 2 1 288 2 1 Gravitinos ~ ~ G K ~, T GG i i i i m m m M 3 / 2 P Decay to gravitinos is typically suppressed by a factor of 100 The modulus decay to Higgsinos and squarks are suppressed as well 17
Cladogenesis: Explicit Model W extra i N u c i X ' ij d c i d c j X M X X M 2 N N N X, X : SM singlet; : Color triplet, hypercharge 4/3 R= +1: N fermions and X scalars R parity conserved Baryogenesis : From decays of (if ) N Or X, X M M decays of (if ) M M 18
Cladogenesis: Explicit Model 1 24 Im[( ) ( ) ] 2 [3F s ( x) F V ( x)] 2 x 1 F s F V x ln(1 ) x 1 x ~ O(1), Im( ) ~ O(1) ~O(0.1) 19
Cladogenesis: Explicit Model Similarly, one can use X, X fields to produce 20
Cladogenesis: N-N Oscillation Oscillation operator: G M 2 '2 1 12 c c c 2 ( u d s ) 4 X M N Oscillation time t = 1/(2.5 x 10-5 G) > 0.86 x 10 8 sec G < 3 x 10-28 GeV -5 ' 1 12 Using this bound for M x ~M N ~ 1 TeV ( )<10-4 ( Choosing the strange quark content of proton to be ~ 1%) 21
Cladogenesis: LHC LHC signal: New Particles: Heavy colored states: SM Singlet: LHC signals: When R=1 new colored states are produced high E T four jets in the final states When R=-1 new colored states are produced, high E T four jets +missing energy [via cascade decays into squarks etc] X, Distinguishing Feature: 4 high E T jets and 4 high E T jets + missing energy X N 22
Conclusion Baryon-DM coincidence explanation requires a connection between the physics of baryon abundance and DM Particle physics models correlate baryon and DM number densities. The mass of the dark matter gets determined from this correlation and the observation of energy densities We propose a non-thermal scenario for the explanation Late time moduli decay is responsible: produces DM abundance and Baryon asymmetry The dilution factor 10-7 -10-9 is the key to explain the Coincidence with a DM mass 5-500 GeV The Baryon asymmetry is generated through the presence of new color triplet fields and SM singlet fields This proposed model has interesting LHC signals 23