1. Neutralino relic density from ILC measurements in the CPV MSSM Sabine Kraml LPSC Grenoble
Based on arXiv:
with G. Bélanger, O. Kittel, H.U. Martyn and A. Pukhov
GDR Supersymétrie  IPHC Strasbourg  April 2008

2. Neutralino relic density from ILC measurements in the CPV MSSM
Motivation
Main aim of ILC is high-precision measurements of new particles: Higgs & beyond the SM (BSM).
BSM often provides a dark matter candidate, cf SUSY!
Hope to determine properties of BSM DM at ILC  make a “collider prediction” of its h2.
In general, expected precision is O(10%) at LHC and few % at ILC  could match WMAP/PLANCK
However, reality could be more demanding …
Nojiri, Polesello, Tovey; Arnowitt et al.; Bambade, Berggren, Richard, Zhang; Martyn; Baltz, Battaglia, Peskin, Wizansky; Berger, Gainer, Hewett, Lillie, Rizzo.
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

3. Neutralino relic density from ILC measurements in the CPV MSSM
MSSM with CP violation
In the general MSSM, gaugino and higgsino mass parameters and trilinear couplings can be complex:
Well known that sparticle and Higgs phenomenology at colliders depends sensitivly on CP phases; important variations in production and decay rates .
In hep-ph/ * we analysed all c0 annihilation channels and showed that CP phases can also have dramatic effects on the relic density
*) Belanger, Boudjema, SK, Pukhov, Semenov, hep-ph/ (PRD73)
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

4. Example: light stau, t-channel
Wh2 too low
coannihilation strip
Wh2 within
WMAP range
Wh2 too high
„stau bulk“
Belanger, Boudjema, SK, Pukhov, Semenov, hep-ph/ (PRD73)
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

5. How well could ILC resolve this?
Pick a point for case study
For 1>110, h2<0.136
For 1=0, relic density would be too large: h2=0.167
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

6. Neutralino relic density from ILC measurements in the CPV MSSM
ILC cross sections
N.B. heavy selectrons to avoid EDM constraints; suppresses neutralino production
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

7. Neutralino relic density from ILC measurements in the CPV MSSM
Threshold scans
Kinematic endpoints
Polarized cross sections
Tau polarization
per-mil level !
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

8. Parameter fit with Markov Chain MC
Perform a fit to the six measurements and  total Xsect at 400 GeV
Free parameters: M1, , tan, ML3,MR3, A, 1, 
Use Markov Chain Monte Carlo (MCMC) to explore parameter space
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

9. Neutralino relic density from ILC measurements in the CPV MSSM
Markov Chain
Dice a starting point, xc, compute its chi^2
Dice another point, xt, in the vinicy of xc. If
accept it in the chain, xc=xt, dice a new xt, etc
Gaussian
distribution p1
found better
point!
better
point! p2 p3
minimum
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

10. 1s and 2s parameter ranges
black: c2<1
green: c2<3.84
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

11. Neutralino relic density from ILC measurements in the CPV MSSM
m – tanb correlation
black: c2<1
green: c2<3.84
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

12. Include Higgs mass in fit? → No
Stop parameters fixed
to their nominal values
green: stop sector undetermined;
blue: stop masses known to 10%
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

13. Results of parameter determination
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

14. Prediction of relic density
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

15. Use CP-odd observables?
Consider
define T-odd asymmetry
A1≠0 would be signal of CP violation. But does not help to constrain Wh2 because A1 symmetric around f1 = 90° 
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

16. Interplay with direct DM detection
spin-independent neutralino-proton cross sections
black: points within 1s, green: points within 2s fitted region.
Present CDMS bound for 80 GeV WIMP is 5*10-8 pb.
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

17. Interplay with EDM measurements (Tl)
Present limit: dTl < 9*10-25 e cm. Future improvement by 2 orders of magnitude would probe most of the parameter space of this scenario
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

18. Neutralino relic density from ILC measurements in the CPV MSSM
Conclusions
Collider determination of Wh2 needs precise measurements of masses *and* couplings → CP phases
Investigated „stau bulk“ scenario in CPV-MSSM: only neutralino1, chargino1, stau1+2 detectable at ILC.
Very good precision on masses and stau mixing  however poor parameter determination  [NB m-tanb]
Parameter fit gives 0.11 < Wh2 < 0.19 at 95% CL
Would need complete –ino system at √s~1-2 TeV; direct DM detection and EDM experiments could help resolve the scenario.
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

19. Neutralino relic density from ILC measurements in the CPV MSSM
backup slides
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

20. Neutralino relic density from ILC measurements in the CPV MSSM
CPV-MSSM » micrOMEGAs
We have implemented the general MSSM Lagrangian with CP-violating phases in CalcHEP/micrOMEGAs
Higgs and sparticle masses and mixing matrices are computed with CPsuperH
ALL annihilation and coannihilation channels included
Coherent and complete analysis of neutralino relic density in the CPV-MSSM; disentangling effects due to shifts in masses and in couplings.
micrOMEGAs: G. Bélanger et al., Comput. Phys. Commun. 149 (2002), hep-ph/
CPsuperH: J.S. Lee et al., Comput. Phys. Commun. 156 (2004), hep-ph/
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

21. Neutralino relic density
c0 LSP as thermal relic: relic density computed as thermally avaraged cross section of all annihilation channels → Wh2 ~ 1/<sv>
expect large effects from modified couplings for nonzero phases
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

22. Neutralino relic density from ILC measurements in the CPV MSSM
Neutralino system
Neutralino mass eigenstates
CP phases modify masses and mixings (couplings)
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

23. Neutralino relic density from ILC measurements in the CPV MSSM
Chargino system
Mass matrix
Interaction with neutralino and W
wino
higgsino fractions (coupling vanishes in the pure bino case)
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

24. Sfermions, 3rd generation
3rd generation can be light and have important phase effects
from trilinear Af couplings and/or m parameter (~ Yuk. coupl.)
Assume 1st & 2nd generation > 10 TeV to avoid EDM constraints
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

25. Neutralino relic density from ILC measurements in the CPV MSSM
Higgs sector
Non-zero phases induce CP violation in the Higgs sector through loop effects → mixing of h,H,A:
Couplings to neutralinos: scalar and pseudoscalar parts
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

26. Neutralino annihilation in CPV-MSSM
Falk, Olive, Srednicki, hep-ph/
P. Gondolo, K. Freese, hep-ph/
T. Nihei, M. Sasagawa, hep-ph/
M. Argyrou et al., hep-ph/
C. Balazs et al., hep-ph/
M. E. Gomez et al., hep-ph/
T. Nihei, hep-ph/
S.Y. Choi, J.G. Kim, hep-ph/
V. Cirigliano et al., hep-ph/
.... concentrated on particular aspects and/or particular channels,
often ignoring coannihilations or Higgs CP-mixing, etc.
.... did not distinguish between effects on masses and on couplings
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

27. Disentangling effect on LSP mass
Up to order-of-magnitude effect for constant LSP mass
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

28. 3. Light staus Important phase effects for c1c1 → tt,
interference of t1, t2 exchanges ! ~
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM

29. Conclusions from hep-ph/0604150
CP phases can have important effects on the relic density of the neutralino LSP.
Implemented the CPV-MSSM into micrOMEGAs.
Detailed analysis of the typical c0 DM scenarios
→ up to order-of-magnitude variations in Wh2
especially in Higgs funnel and (mixed) higgsino region.
Important changes in couplings, interference effects
Note: we have singled out kinematic effects. ~
S. Kraml
Neutralino relic density from ILC measurements in the CPV MSSM