Neutralino Dark Matter with CP Violation Sabine Kraml, CERN

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Neutralino Dark Matter with CP Violation
Sabine Kraml, CERN

• GDR Supersymétrie
• Ecole Polytechnique, 5-7 April 2006
• in collab. with G. Bélanger, F. Boudjema, A.
  Pukhov A. Semenov

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MSSM with CP violation

• In the general MSSM, gaugino and higgsino mass
  parameters and trilinear couplings can be
  complex
• CP violation (CPV) in the Standard Model is not
  sufficient to explain the baryon asymmetry in the
  Universe
• ? we do need new sources of CPV beyond the SM.
• In the MSSM, the sparticle and Higgs
  phenomenology depends sensitivly on CP phases
  important variations in production and decay
  rates ? similar influence on Wh2?

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Neutralino relic density
c0 LSP as thermal relic relic density computed
as thermally avaraged cross section of all
annihilation channels ? Wh2 1/ltsvgt
expect large effects from modified couplings for
nonzero phases
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Neutralino system
Neutralino mass eigenstates
CP phases modify masses and mixings (couplings)
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Chargino system

• Mass matrix
• Interaction with neutralino and W

higgsino fractions (coupling vanishes in the pure
bino case)
wino
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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 gt 10 TeV to avoid
  EDM constraints

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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

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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/0112278 CPsuperH J.S.
Lee et al., Comput. Phys. Commun. 156 (2004),
hep-ph/0307377
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Previous studies

• Falk, Olive, Srednicki, hep-ph/9502401
• P. Gondolo, K. Freese, hep-ph/9908390
• T. Nihei, M. Sasagawa, hep-ph/0404100
• M. Argyrou et al., hep-ph/0404286
• C. Balazs et al., hep-ph/0412264
• M. E. Gomez et al., hep-ph/0506243
• T. Nihei, hep-ph/0508285
• S.Y. Choi, J.G. Kim, hep-ph/0602109
• V. Cirigliano et al., hep-ph/0603246

.... 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
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1. Annihilation into gauge bosons

• cc ? WW / ZZ mainly through t-channel chargino /
  neutralino
• exchange typically also some annihilation into
  Zh, hh
• Does not occur for a pure bino LSP needs
• to be mixed bino-higgsino
• Pure higgsino LSP
• neutralino1,2 and chargino1
• are a mass-degenerate triplet,
• (co)annihilation too efficient
• Right relic density for
• (m-M1)/M1 0.3
• Note wino case is different

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Scan over phases in M1-m plane
0.094 lt Wh2 lt 0.129 WMAP band
M1 0.7 m main channel is annihilation into
WW LSP has 25 higgsino admixture
Blue WMAP-allowed range for zero phases Green
same for the CP-violating case (arbitrary phases
of M1, m, ...)
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Same in terms of neutralino and chargino masses
no CP phases
with CP phases
With CP phases, much smaller neutralino-chargino
mass differences can be in agreement with WMAP
bound !
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In M1-arg(M1) plane, m 200 GeV, tanb 10
D0.16
Wh2 lt 0.094
0.094 lt Wh2 lt 0.129 WMAP band
D0.4
Wh2 gt 0.129
Key parameter is higgsino fraction fh ? c0c? W
coupling fh decreases with arg(M1), hence Wh2
increases for const M1
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Disentangling effect on LSP mass
Up to order-of-magnitude effect for constant LSP
mass
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2. Analysis of Higgs funnel with CPV

• G. Bélanger, F. Boudjema, SK, A. Pukhov and A.
  Semenov,
• in Les Houches Physics at TeV colliders
  workshop 2005,
• BSM working group report, hep-ph/0602198,
  pp.37-44.
• Order-of-magnitude effects due to
  scalar-pseudoscaler mixing
• See also S.Y. Choi and J.G. Kim, hep-ph/0602109

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Interferences in chargino and Higgs exchanges
Blue WMAP-allowed range for zero phases Green
same for the CP-violating case (arbitrary phases
of M1, m, Af)
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A closer look to the Higgs funnel, cc ? bb
Bino-like LSP, mc 150 GeV, small H/A mixing
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Phase dependence of neutralino-Higgs couplings
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Disentangling kinematic effects
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3. Light staus
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Summary

• 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.
• Paper in preparation

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• For a precise prediction of Wh2
• from experiments at colliders we need
• not only precision measurements of most of the
  SUSY spectrum
• but of all the relevant couplings,
• including possible CP phases