Baryogenesis and dark matter in the nMSSM
Transcript of Baryogenesis and dark matter in the nMSSM
Baryogenesis and dark matter in the nMSSM
C.Balázs, M.Carena, A. Freitas, C.Wagner
Phenomenology of the nMSSM from colliders to cosmology
arXiv:0705431
C. Balázs, Monash U Melbourne BG & DM in the nMSSM DSU, June 6, 2007 1/18
Minimal Supersymmetric Standard Model
Explains the origin of
è mass: radiative dynamics Ø
electroweak symmetry breaking
è dark matter: R-parity Ø
stable, neutral WIMP LSP
è baryons: lepto-, baryogenesis Ø
baryon-antibaryon asymmetry
è ...
But the Higgs sector of the MSSM is problematic
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Problems with the Higgs sector of the SSM
è the m problem:
W m H`
1.H`
2 in not natural
è the fine-tuning problem:
tension between mh > 114 GeV and ... stops
è the baryogenesis problem:
electroweak baryogenesis demands mh d 120 GeV
è ... put your own problem here ...
...
Fortunately, it's is easy to fix these problems while
keeping radiative EWSB intact
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nMSSM: nearly MSSM
— Discreet symmetries of super- & Kahler potentials
Z5R, Z7
R Õ U 1 R' where R' = 3R + "PQ"
to prevent domain walls and large tadpoles
è Superpotential
W = WMSSM + m122
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄl
S`
+ l S`
H`
1.H`
2
è Scalar potential
V = VMSSM + tS S + h.c. + mS2 S 2 + al S H1.H2 + h.c.
è New parameters
vS, l, al , m12, mS, tS
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Positive features of the nMSSM
— Solves m problem naturally
W = WMSSM + m122
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄl
S`
+ l S`
H`
1.H`
2
è m = l S = l vS set by EW scale
— Alleviates fine tuning in Higgs/stop sector
mh2 § mZ
2 cos2 2 b + 2 l2ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄgèèè2 sin2 2 b
è tree level lightest Higgs mass limit relaxed
— Tree level cubic term of scalar potential
V = VMSSM + tS S + h.c. + mS2 S 2 + al S H1.H2 + h.c.
è assists a strongly 1st order EW phase transition
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Electroweak baryogenesis in the nMSSM
— Measured hB ¨ strongly 1st order EWPT ¨ large OP
fC/TC t 1
è strength of EWPT ¨ minimum of finite T eff. potential
Veff(f,T) = (— m2+aT2)f2 — g T f3+ lÅÅÅÅÅ4 f4+ ...
è V eff minimal for 0 < f if
l fCÅÅÅÅÅÅÅÅTC~ gÅÅÅÅÅl Ø g affects OP
è g generated byl SM : bosonic loops Ø g ~g 3
l MSSM : sc. loops Ø g ~ y 3
l nMSSM : tree level Ø g ~al
è MSSM: light stop induces strongly 1st order EWPT
nMSSM: tree level al S H1.H2 coupling does the same
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Dark matter in nMSSM
— Neutralinos
Zé =
M1 . . . .
0 M2 . . .
-cb sw mZ cb sw mZ 0 . .
sb cw mZ -sb cw mZ l vS 0 .
0 0 l v2 l v1 0
è unification assumption: |M2|= a2/a1|M1|
è EWBG Ø low tanb &
Arg(M1) = Arg(M2) = fM ~ 0.1
è typical lightest neutralino (Zè
1): mostly singlino
mZé
1~ 2lv1v2vS/(v1
2 +v22+vS
2) d 60 GeV
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All matter in nMSSM
— Neutralino relic density
è Zè
1 light Ø no coannihilations
dominant annihilation channel: Zè
1 Zè
1 Ø Z* Ø SM
Menon, Morrissey, Wagner 2004
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Can we "measure" WZè
1 at colliders?
— WZè
1(mZ
è1, sv ) under standard thermal assumptions
— nMSSM benchmark: point "A"
tanb l vS al ma M2 fM
1.70 0.619 –384 373 923 245 0.14
GeV GeV GeV GeV
— Extracting physical parameters from cross sections
è generate LHC & ILC events (tree & parton level w/
BGs, jet broadening, ...)
è construct appropriate invariant mass distributions
è reconstruct masses (couplings) from distributions
è determine central values and precision
è scan around the central value in a precision window
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Mass determination at the LHC
— Typical production/decay chain:
squarks/gluinos Ø
charginos/neutralinos Ø
leptons/jets
è typical invariant mass spectra (lumi 300 fb-1)
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Mass determination at the LHC
è four kinematic (mass) edges Ø four mass parameters
mll,max = mZé
2–mZ
é1= 73.5±0.6 GeV
m jll,max,22 = (mZ
é2
2 –mZé
1
2 )(mb1é2 –mZ
é2
2 )/mZé
2
2 = 447.0±20.0 GeV
m jll,min,32 = f1(mZ
é1,mZ
é3,mZ
é2,mb
é1)= 256.2±7.0 GeV
m jll,max,32 = f2(mZ
é1,mZ
é3,mZ
é2,mb
é1)= 463.5±9.0 GeV
è results for individual masses
mZé
1= 33-18
+32 GeV mZé
2= 107-18
+33 GeV
mZé
3= 181-10
+20 GeV mbé
1= 499-17
+30 GeV
è absolute precision is reasonable but Zè
1 is very light!
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Mass determination at the ILC
— Processes utilized at ILC (lumi 500 fb-1)
e+ e- Ø Wè1+ Wè
1- e+ e- Ø Zè 2 Zè 4 e+ e- Ø Zè 3 Zè 4
è results for individual masses
mZé
1= 33.3±1.1 GeV mZ
é2= 106.6-1.7
+1.4 GeV
mZé
3= 181.5±5.2 GeV mWè
1+= 165 ± 0.3 GeV
è after inclusion of e+ e- Ø Wè1+ Wè
1- threshold scan
mZé
1= 33.3-0.3
+0.4 GeV
è resulting precision of WZé
1 is comparable to WMAP!
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Dark matter direct detection
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Dark matter indirect detection
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Conclusions
nMSSM improves on MSSM: no m problem, less
fine-tuning, looser constraints on EWBG
All matter in the Universe can be simultaneously
generated in the nMSSM
Model can be discovered at LHC, direct detection,
and low energy experiments (e-EDM)
ILC precision is critical for determining astrophysical
parameters: relic density, WIMP-nucleon scattering, ...
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