mesino oscillations AKSHAY GHALSASI, DAVE MCKEEN, ANN NELSON - PowerPoint PPT Presentation

Baryogenesis via mesino oscillations AKSHAY GHALSASI, DAVE MCKEEN, ANN NELSON arxiv:1508.05392

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

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

4 Introduction and Motivation

Evidence for baryogenesis 5  Universe is made up of baryons

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

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

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

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

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

12 Oscillations and CP Asymmetry

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

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

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

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

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

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

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

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 as our benchmark value

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

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

24 Cosmology

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

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

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

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

Constraints on decay rate 29

Asymmetry dependence on α 𝐶 30

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

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 THANK YOU! QUESTIONS?

Constraints on couplings from 34 displaced vertices  Displaced vertices search give us 𝑑τ < 1 𝑛𝑛  Φ → quarks :  Φ → N 1 → quarks :  These constraints don’t apply if  Mass independent constraints from BBN are 𝑃 10 6 weaker

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

Kaon oscillation constraints 36 s d N i N j d * s *  Constraints from K L and K S mass difference  Constraints from CP violation in Kaon system  B meson oscillations aren’t as constraining