neutralino dark matter with cp violation sabine kraml, cern
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Neutralino Dark Matter with CP Violation
Sabine Kraml, CERN
GDR matière noir,
Montpellier, 13-14 Feb 2006
in collab. w. G. Bélanger, F. Boudjema, A. Pukhov & A. Semenov
S. Kraml Neutralino dark matter with CP violation 2
Relic density of WIMPs
(1) Early Universe dense and hot; WIMPs in thermal equilibrium
(2) Universe expands and cools; WIMP density is reduced through pair annihilation; Boltzmann suppression: n~e-m/T
(3) Temperature and density too low for WIMP annihilation to keep up with expansion rate → freeze out
Final dark matter density: h2 ~ 1/<v>Thermally avaraged cross section of all annihilation channels
S. Kraml Neutralino dark matter with CP violation 3
Neutralino LSP of the MSSM
The generic O(100) GeV neutralino LSP has a too large relic density → need specific mechanism(s) for efficient enough annihilation
0.094 < h2 < 0.129 puts strong bounds on the parameter space
S. Kraml Neutralino dark matter with CP violation 4
mSUGRA parameter space
GUT-scale boundary conditions: m0, m1/2, A0
4 regions with good h2
bulk (const. by LEP mh limit)
co-annihilation (small M)
Higgs funnel (tan ~ 50)
focus point (higgsino scenario)
Analogous scenarii in the general MSSM
S. Kraml Neutralino dark matter with CP violation 5
Neutralino system
Neutralino mass eigenstates
Gauginos
Higgsinos
→ LSP
Gaugino and higgsino mass terms can be complex
→ CP violation ←
S. Kraml Neutralino dark matter with CP violation 6
CP violation
In the general MSSM, gaugino and higgsino mass parameters and trilinear couplings can be complex:
Sparticle production and decay rates strongly depend on CPV phases → expect similar influence on <v>
Caution: also the sparticle masses depend on phases
→ disentangle effects from kinematics and couplings
NB1: M2 can also be complex, but its phase can be rotated away.
NB2: CPV phases are strongly constrained by dipole moments;
we set =0 and assume very heavy 1st+2nd generation sfermions
S. Kraml Neutralino dark matter with CP violation 7
CP violation: 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 dark matter with CP violation 8
Previous studies of relic with CPV
... typically concentrate on some particular aspect;no complete, general analysis so far; no public tools
S. Kraml Neutralino dark matter with CP violation 9
CPV with 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
Fully automatical computation of the relic density;
all contributing channels automatically included!
Now performing general analysis of CPV-MSSM parameter space ....
micrOMEGAs: G. Bélanger et al., Comput. Phys. Commun. 149 (2002), hep-ph/0112278CPsuperH: J.S. Lee et al., Comput. Phys. Commun. 156 (2004), hep-ph/0307377
S. Kraml Neutralino dark matter with CP violation 10
Scan over phases in M1- plane
Blue: WMAP-allowed range in the CP-conserving MSSMGreen: same for the CP-violating case (arbitrary phases of M1 and )
M1 ~
main channel is annihilation into WW
S. Kraml Neutralino dark matter with CP violation 11
With increasing (M1), the LSP mass increases; annihilation into WW becomes
less efficient while coannihilation with charginos can set in. Hence h2 ↑ or ↓ ...
()=180°
()=0°
S. Kraml Neutralino dark matter with CP violation 12
Scan over phases in M1- plane
mH+ = 500 GeVHiggs funnel
We find the conventional Higgs funnels just above and below 2m=mHi.The allowed bands are again wider than in the CP-conserving case.
S. Kraml Neutralino dark matter with CP violation 13
A closer look to the Higgs funnel
M1 = 150, M2 = 300, At = 1200 GeV, tan = 5
masses of 3rd gen: 500 GeV, 1st+2nd gen: 10 TeV
>>M1 → bino-like LSP, m ~ 150 GeV
h2 < 0.129 needs annihilation through Higgs
Scenario 1: = 500 GeV → small mixing in Higgs sector Scenario 2: = 1 TeV → large mixing in Higgs sector
Higgs mixing ~ Im(At)
S. Kraml Neutralino dark matter with CP violation 14
Scenario 1, = 500 GeV
S. Kraml Neutralino dark matter with CP violation 15
Scenario1: dependence on phase of At
dm2 = mh2−2m
WMAP allowed region follows position of h2 pole, deviation only 4%
0.094 < h2 < 0.129
h2 < 0.094
S. Kraml Neutralino dark matter with CP violation 16
When arg(M1) increases, h2 drops This is because m increases and hence dm2 decreases
Scenario1: dependence on phase of M1
0.094 < h2 < 0.129
h2 < 0.094
S. Kraml Neutralino dark matter with CP violation 17
Keeping LSP and Higgs masses fixed
gS,P(h2) gS,P(h3)
(M1)=0 (~0, -.06) (-.05, ~0)
(M1)=90° (.05, -.01) (-.002, .04)
Scalar/pseudos. parts of H copuling
S. Kraml Neutralino dark matter with CP violation 18
Scenario 2, large Higgs mixing
Smaller mass difference needed
S. Kraml Neutralino dark matter with CP violation 19
Order-of-magnitude effects due to t
Green bands: 0.94 < h2 < 0.129
dmi = mhi - 2mLSP, i=2,3
h3 h3
h3
h2
S. Kraml Neutralino dark matter with CP violation 20
h3
h3
h2
h2 and h3 interchange scalar-pseudoscalar character
S. Kraml Neutralino dark matter with CP violation 21
h3
Not only position but also height of peak varies.
m = −1.5
m = +1.5 GeV
Even for fixed masses order-of-magnitude variation in h2!
S. Kraml Neutralino dark matter with CP violation 22
Conclusions
CP-violating phases in the MSSM can have sizeable effects for collider phenomenology as well as for the relic density of the LSP
Implemented the CPV-MSSM into micrOMEGAs found up to order-of-magnitude effects in h2
no generically new features (same channels as in CP-conserving case) but important changes in the couplings; need to disentangle kinematic effects
detailed analysis of Higgs funnel (Higgs CP mixing) general analysis of annihilation is on the way
S. Kraml Neutralino dark matter with CP violation 23
Green bands: 0.094 < h2 < 0.129
Yellow region: h2 < 0.094
Phase dependences, scenario 1, = 500 GeV
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