Baryogenesis via mesino oscillations

Transcription

1 Baryogenesis via mesino oscillations AKSHAY GHALSASI, DAVE MCKEEN, ANN NELSON arxiv:

2 The one minute summary 2 Mesino a bound state of colored scalar and quark Model analogous to Kaon system Mesinos form after the QCD hadronization temp Oscillations analogous to Kaon system give CP violation Baryon violating decays give baryogenesis

3 Outline 3 Introduction and Motivation The Model Oscillations and CP Asymmetry Experimental Constraints Cosmology Conclusion

4 Introduction and Motivation 4

5 Evidence for baryogenesis 5 Universe is made up of baryons

6 No baryogenesis in SM 6 Sakharov conditions Baryon number violation (sphalerons) C and CP Violation (CKM phase not enough) Departure from thermal equilibrium (no first order PT ) Models of baryogenesis require high reheating temperature

7 Reheating temperature can be low 7 No evidence of high reheating temperature Many reasonable theories favor a low reheating scale Gravitino production in SUSY extensions of SM(Moroi et al 83) Isocurvature perturbations(fox et al 04) There do exist low scale baryogenesis models(claudson et al 84, Dimopolous et al 87)

8 The Model 8

9 Particle content 9 colored scalars singlet fermions majorana mass N 2,3 O(TeV) N 1

10 Complex phases all 9 phases remain real and diagonal two complex phases remain 10 Oscillations and CP violation B violation

11 Decay Modes 11 d i d i * s u j Baryon +mesons s* u* j Antibaryon +mesons N 1 N 1 s d i N 1 +mesons s* d i * N 1 +mesons

12 12 Oscillations and CP Asymmetry

13 On-shell and off-shell oscillations 13 Off shell diagrams N 2 s* s N 2 O(TeV) N 1 On shell diagrams via common final states s N 1 s*

14 Off-shell contribution 14 Off shell oscillations M 12 : s s* N 1,2 Form factor Berger et al 13 N 2 N 1

15 On-shell contribution 15 Contributions to Γ 12 : s* We want to be in the squeezed limit In squeezed limit one can show s

16 Hamiltonian is not diagonal 16 Hamiltonian without oscillations With oscillations we get off diagonal terms

17 Diagonalizing the Hamiltonian 17 Hamiltonian has off diagonal terms, new eigenstates are Assuming a state starts as at t = 0 then CP violation gives favoring one state over another

18 CP asymmetry 18 Can show asymmetry per mesino-antimesino pair is given by branching ratio into baryons Lets define and then we have We expect generally Can show

19 Experimental Constraints 19

20 Experimental Signatures 20 d i 2 jets q u j soft quark, no jet d i 2 jets N 1 N 1 u j d k q d i soft quarks, no jet usually soft quark, no jet

21 Constraints on mass 21 Constraints from squarks decaying into b and light quark: (CMS) Effective constraints from squark decaying to light quarks: (CMS) Constraints from 3 jet events: We take value as our benchmark

22 Couplings 22 upper bounds from Kaon oscillations, n തn oscillations and diinucleon decays, lower bounds from displaced vertices upper bounds from n തn oscillations and dinucleon decays upper bound from cosmology

23 Constraints summary 23 Totally fine set of couplings for : Constraints only get weaker with increasing mass

24 Cosmology 24

25 Cosmic Story T 25 T = 200 MeV N 3 N 3 N 3 N 3 N s s* CP Violation T = 1 MeV Baryons Anti Baryons

26 N 3 does not annihilate 26 Number density of N 3 at hadronization temp T c For N 3 to last until T c we need Small Yukawa imply N 3 annihilations are slower than expansion rate. So most of the N 3 survives till T c

27 Exact Solution 27 We can coevolve the radiation, N 3 and baryons produced from their decay to get the exact solution

28 Sudden Decay Approximation 28 Baryon to entropy ratio in sudden decay approximation Ratio of matter and radiation energy densities for ent. dil. However and so

29 Constraints on decay rate 29

30 Asymmetry dependence on α B 30

31 Possible signatures 31 Finding colored scalars at LHC (1 TeV at 1000 fb -1 ) final states jets will have third generation quarks mostly 2-jet decays but will have 3-jets sometimes possible displaced vertices signature same sign tops (Berger 13) CP violation in same sign tops hard to see at LHC Any signature needs to be consistent with neutron-antineutron oscillations and B meson and Kaon oscillations

32 Conclusions and future work 32 If there is a scalar quark it can form mesinos CP violation in mesino oscillations can be the source for baryogenesis In order to get enough CP violation we need the singlets to be very close in mass with mesinos

33 33 THANK YOU! QUESTIONS?

34 Constraints on couplings from 34 displaced vertices Displaced vertices search give us cτ < 1 mm Φ quarks : Φ N 1 quarks: These constraints don t apply if Mass independent constraints from BBN are O 10 6 weaker

35 Constraints from Rare Processes 35 B = 2, neutron-antineutron oscillation: For we get Dinucleon to Kaon decay constraints for Easily satisfied if

36 Kaon oscillation constraints s N i d 36 d * N j s * Constraints from K L and K S mass difference Constraints from CP violation in Kaon system B meson oscillations aren t as constraining