1. Baryogenesis at Electroweak scale
and EDM in MSSM
Yingchuan Li
University of Wisconsin, Madison
YL, S. Profumo, M. Ramsey-Musolf, PRD 78, , 2008; PLB 673, 95, 2009.
V. Cirigliano, YL, S. Profumo, M. Ramsey-Musolf, Arxiv:
Nov. 3rd, 2009, UC-Davis, CA

2. What does it require in MSSM?
Outline
Electroweak baryogenesis
Why ruled out in SM?
Why possible in MSSM?
What does it require in MSSM?
The interplay between EWB and EDM in MSSM
Various contributions to neutron and atomic EDMs in MSSM;
Chargino-neutralino two-loop: the most relevant contribution;
Bino-driven EWB with highly suppressed EDMs;
Conclusion 2 2 2 2

3. The origin of matter and energy
Baryon asymmetry of Universe:
(WMAP)
(BBN)
Sakharov conditions:
Baryon number violation;
C and CP violation;
Departure from thermal equlibrium. 4

4. Scenarios of baryogenesis
Planck scale baryoenesis;
GUT baryogenesis;
Baryogenesis via leptogenesis
(Fukugita & Yanagita 1986; M. Luty 1992);
Afleck-Dine baryogenesis;
Electroweak baryogenesis;
most testable scenario! 5 5

5. Electroweak baryogenesis process
bubble wall expands fast
CP violating
interactions
Sphaleron
process
Not washed out if PT
is strongly 1st order
freeze in as bubble
wall expands rapidly 6 6

6. Electroweak baryogenesis in SM
No 1st order phase transition:
1st order:
Light bosonic
d.o.f
LEP bound: 7 7 7

7. Electroweak baryogenesis in SM
Not enough CP violations:
with
is needed for explaining the observed baryon asymmetry!
NEED: (1) New bosonic degrees of freedom;
(2) New CP violation source.
Beyond SM physics 8 8 8 8

8. SUSY – one of the most studied BSM
Stabilize the electroweak scale.
Help gauge coupling unification.
Provide dark matter candidate.
Help electroweak baryogenesis to happen? 9 9 9 9 9

9. MSSM More particles : New parameters: Fermions + Bosons
quarks, leptons + squarks, sleptons
New bosonic degrees of freedom makes phase transition 1st order.
gauginos gauge bosons
two higgsino doublets two higgs doublets
New parameters:
ratio of vevs:
SUSY invariant couplings:
Soft breaking couplings:
Combinations of new parameters give new physical CP violation phases. 10 10 10 10

10. Chargino-neutralino sector:
EWB in MSSM
Strong 1st order phase transition:
(Carena, et al. 2008)
Light Higgs:
Light RH stop:
Heavy LH stop:
Extra CP violation phase:
Chargino-neutralino sector:
Stop sector:
Bino-driven
Wino-driven 11 11 11 11 11

11. EWB in MSSM Resonant enhancement of CP violation:
(Carena, et al. 1997,2001; Lee, et al. 2004)
Chargino-neutralino scenario
preferred !
Stop scenario
not preferred!
mA = 100 GeV
mA = 150 GeV
mA = 400 GeV
Crucial parameters in chargino-neutralino scenario:
Can large phases and small mass scales survive EDM bounds? 12 12

12. EDM – probe of CP violation
Electric dipole moment:
CPT
P and T violation
P and CP violation
Experimental searches:
Future reach
SM values
Current bounds 13 13

13. Various contributions to EDMs.
CP violating phases in MSSM
New CP violation sources:
Studied, but incomplete
CP-odd
operators:
Extensively studied
Neutron and
atom EDMs: 14 14 14 14

14. Compatibility between EWB and EDM?
Compatibility condition
CP odd op.
Phases ? 15

15. 4-fermion and 3-gluon in MSSM
CP-odd 4-fermion operator:
Induced by phases:
Suppressed with low
CP-odd 3-gluon operator:
Induced by phases:
Ssuppressed with small phases:

16. Compatibility between EWB and EDM?
CP odd op.
Phases
Compatibility condition ? ? ? ? ? ? ? ? ? ? ? 17 17

17. One-loop EDM and chromo-EDM in MSSM
One-loop EDM and chromo-EDM operators:
Induced by phases:
Always involve first two generations
of squarks and sleptons;
Suppressed with
a solution to SUSY CP problem;
A.G.Cohen,D.B.Kaplan,A.E.Nelson,PLB,1996
a way to reconcile with EW baryogenesis;

18. Compatibility between EWB and EDM?
CP odd op.
Phases
Compatibility condition ? ? ? ? ? ? ? 19 19 19

19. Two-loop EDM and chromo-EDM in MSSM
Stop-sbottom-stau two-loop:
Induced by phases:
Involve the 3rd generation of
squarks, sleptons and Higgs:
Suppressed with:
Chargino-neutralino two-loop:
Induced by phases:
Involve the charginos,
neutralinos and Higgs:
Most relevant part to EWB. 20

20. How to suppress various EDM?
CP odd op.
Phases
Compatibility condition
Not obvious. ?
Full calculation is needed. 21 21 21 21

21. Chargino-neutralino 2-loop EDM: diagrams
Complete diagrams:
Calculated:
Uncalculated:

22. Chargino-neutralino 2-loop EDM: gauge choice
Non-linear gauge:
K. Fujikawa, PRD, 1973; J. Romao, A. Barroso, PRD, 1987
M. Gavela, G. Girardi, C. Malleville, P. Sorba, Nucl. Phys.B,1981
No couping: diagram (c) vanishes.
Taking the non-linear Landau gauge ( ) limit: diagram (d) vanishes.

23. Chargino-neutralino 2-loop EDM: upper-loop structures
Ward-identity consistent structures:
Structures for each contributions: 24

24. Chargino-neutralino 2-loop EDM: analytic result
YL, S. Profumo, M. Ramsey-Musolf, arXiv:

25. YL, S. Profumo, M. Ramsey-Musolf, arXiv:0806.2693
Chargino-neutralino 2-loop EDM: numerical result
ZA and WH are dominant contributions
Ref. point:
YL, S. Profumo, M. Ramsey-Musolf, arXiv:

26. Chargino-neutralino 2-loop EDM: bino v.s. wino contribution
Very different contribution
from bino and wino phases
Suppression is due to many aspects:
Neutralino only appears in WH and WW: 20%
In WH and WW:
Another factor of 0.3 is presumably from that, in WH and WW,
W boson only couple to wino and higgsino.
YL, S. Profumo, M. Ramsey-Musolf, arXiv:

27. Comparing bino- and wino-driven EWB
Electron EDM:
Ref. point:
YL, S. Profumo, M. Ramsey-Musolf, arXiv:

28. Comparing bino- and wino-driven EWB
Neutron EDM:
Ref. point:
Bino-driven EWB can happen with highly suppressed EDMs!
YL, S. Profumo, M. Ramsey-Musolf, arXiv:

29. Compatibility between EWB and EDM?
CP odd op.
phases
Compatibility condition
Not obvious.
Bino-driven EWB scenario! 30 30 30 30 30
YL, S. Profumo, M. Ramsey-Musolf, arXiv:

30. Lower bound on phase from EWB in MSSM
V. Cirigliano, YL, S. Profumo, M. Ramsey-Musolf, arXiv:

31. Lower bound on EDM from MSSM EWB32
Lower bound on EDM from MSSM EWB
Lower bounds of EDMs are within the reach of next generation of EDM experiments!
V. Cirigliano, YL, S. Profumo, M. Ramsey-Musolf, arXiv:

32. Conclusions & outlook Thank you !!!
EWB in SM is ruled out, but EWB in MSSM, either
bino-driven or wino-driven, remains possible.
EWB in MSSM is strongly constrained by EDM experiments.
We calculate the full chargino-neutralino 2-loop EDMs,
which is the most relevant part to EWB in MSSM.
We observe that the bino-driven EWB is much less
constrained from EDM bounds than wino-driven EWB.
The lower bounds on EDMs are within the reach of next
generation of EDM experiments.
Possible signature of large bino phase at LHC is under study.
Thank you !!!