Cosmology and the ILC
G. Bélanger
LAPTH- Annecy
PLAN
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Cosmology <-> colliders
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Dark matter
Baryon asymmetry
Dark energy?
Neutralino dark matter
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Precision studies
Correlation with direct/indirect detection
Dark matter : beyond MSSM
Electroweak Baryogenesis
Conclusions
What is the universe made of?
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Although evidence for dark
matter has been around for a
while both at scale of galaxy
clusters (Zwicky 1933) and of
galaxies (rotation curves), in
2003 with CMB anisotropy
map achieve precise
determination of
cosmological parameters
What is the universe made of?
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In recent years : new
precise determination
of cosmological
parameters
Data from CMB
(WMAP) agree with the
one from clusters and
supernovae
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Dark matter: 23+/- 4%
Baryons: 4+/-.4%
Dark energy 73+/-4%
Neutrinos < 1%
Search for dark matter
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In 2003 WMAP has measured
relic density +/-15% (2σ)
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This year new results
In 2007 PLANCK will start
operating, goal is to reach +/5-6% on relic density(2σ)
In 2008 LHC will start, might
have discovery and
measurements of
supersymmetric particles (or
other NP) within a few years
In the meantime direct
detection and indirect
detection experiments
continue to run with improved
detectors
HEPAP subpanel report on
future particle colliders
What is dark matter/dark energy
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Dark matter
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Related to physics at weak
scale
New physics at weak scale can
also solve EWSB
Many possible solutions: new
particle that exist in some NP
models, not necessarily
designed for DM
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Dark energy
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Related to Planck scale
physics
NP for dark energy might affect
cosmology and dark matter
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Neutrinos (they exist but only
small component of DM)
Supersymmetry with R parity
conservation
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Neutralino LSP
Gravitino
Axino
Kaluza-Klein dark matter
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UED (LKP )
LZP is neutrino-R (in
Warped Xdim models with
matter in the bulk)
Branons
Little Higgs with T-parity
……
Relic density of wimps
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In early universe WIMPs are
present in large number and they
are in thermal equilibrium
As the universe expanded and
cooled their density is reduced
through pair annihilation
Eventually density is too low for
annihilation process to keep up
with expansion rate
• Freeze-out temperature
LSP decouples from standard
model particles, density depends
only on expansion rate of the
universe
Freeze-out
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Relic density
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A relic density in agreement with present
measurements Ωh2 ~0.1 requires typical
weak interactions cross-section
Accuracy on relic density of LSP
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Goal is to reach at least the same precision on the
prediction of the relic density as the experimental
one
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Right now depending on particle physics models
(even if only consider supersymmetry) predictions
vary by orders of magnitude
For different cosmological model also vary by
orders of magnitude
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Changes in H affect the freeze-out temperature
New terms in Boltzmann equations
Dark matter : cosmo/astro/pp
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Wimps have roughly right value for relic density
Neutralinos are wimps but not all SUSY models are acceptable
Precise measurement of relic density  constrain models
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Generic class of SUSY models that are OK
Direct/Indirect detection : search for dark matter  establish
that new particle is dark matter  constrain models
Colliders : which model for NP/ prediction for σv/confront
cosmology
• LHC: discovery of new physics, dark matter candidate and/or
new particles
• ILC: extend discovery potential of LHC + precision
measurements
How well this can be done strongly depends on model for NP
Neutralino LSP
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Prediction for relic density depend on parameters of
model
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Mass of neutralino LSP
Nature of neutralino : determine the coupling to Z, h, A …
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M1 <M2< bino
 <M1,M2 Higgsino
M2<M1<  Wino
Neutralino annihilation
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3 typical mechanisms for
χ annihilation
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Bino annihilation into ff
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Mixed bino-Higgsino (wino)
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• σ ~ mχ2/mf 4
• Coupling depends on
Z12,Z13,Z14, mixing of LSP
Annihilation near resonance
(Higgs)
Neutralino annihilation
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3 typical mechanisms for
χ annihilation
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Bino annihilation into ff
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Mixed bino-Higgsino (wino)
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• σ ~ mχ2/mf 4
• Coupling depends on
Z12,Z13,Z14
Annihilation near resonance
(Higgs)
• Need some coupling to A,
some mixing with Higgsino
Coannihilation
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If M(NLSP)~M(LSP) then
maintains thermal
equilibrium between NLSP-LSP even after SUSY particles decouple from
standard ones
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Relic density depends on rate for all processes involving LSP/NLSP  SM
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All particles eventually decay into LSP, calculation of relic density
requires summing over all possible processes
Exp(- ΔM)/T
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Important processes are those involving particles close in mass to LSP
Public codes to calculate relic density: micrOMEGAs, DarkSUSY, IsaRED
Neutralino co-annihilation
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Can occur with all
sfermions, gauginos
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Bino LSP (sfermion
coannihilation)
Higgsino LSPcoannihilation with
chargino and
neutralinos
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What happens in generic SUSY models,
does one gets the right value for the relic
density?
• mSUGRA (only 5 parameters)
• M0, M1/2, tan β, A0, 
• Other models  MSSM (at least 19
parameters)
The mSUGRA case
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Theoretical assumption: the model
is known mSUGRA (CMSSM)
Useful case study contains (almost)
all typical processes for neutralino
(co)-annihilation
bino – LSP :annihilation in fermion
pairs
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In most of mSUGRA parameter space
Works well for light sparticles but hard to
reconcile with LEP/Higgs limit (small
window open)
Sfermion coannihilation
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Staus or stops
More efficient, can go to higher masses
Mixed bino-Higgsino: annihilation into
W/Z/t pairs
Resonance (Z, light/heavy Higgs)
Mt=178
Mt=175GeV
The mSUGRA case -WMAP
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Bino – LSP
Sfermion Coannihilation
Mixed Bino-Higgsino
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Annihilation into W pairs
In mSUGRA unstable region, mt
dependence, works better at
large tanβ
Resonance (Z, light/heavy
Higgs)
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LEP constraints for light Higgs/Z
Heavy Higgs at large tanβ
(enhanced Hbb vertex)
WMAP and SUSY dark matter
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The mSUGRA model seems fine-tuned (either small ΔM or
Higgs resonance) .
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Not generic of other SUSY models, a good dark matter
candidate is a mixed bino/Higgsino ….
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The LSP is bino
In particular, main annihilation into gauge boson pairs works well
for Higgsino fraction ~25%
The mixed bino/Higgsino can be found in many models:
mSUGRA (focus), non-universal SUGRA, string inspired
(moduli-dominated) models, split SUSY, NMSSM….
Which scenario? Potential for
SUSY discovery at LHC/ILC
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Some of these scenarios will be probed
at LHC/ILC and/or direct /indirect
detection experiments
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Corroborating two signals SUSY dark
matter
LHC
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Squarks, gluinos < 2- 2.5 TeV
Sparticles in decay chains
mSUGRA: probe significant parameter
space, heavy Higgs difficult, large m0m1/2 also.
Other models : similar reach in masses
ILC
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Production of any new sparticles within
energy range
Extend the reach of LHC in particular in
“focus point” of mSUGRA
Baer et al., hep-ph/0405210
Probing cosmology using collider
information
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Within the context of a given model can one make precise predictions
for the relic density at the level of WMAP(10-15%) and even PLANCK
(3-6%) (2007) therefore test the underlying cosmological model.
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Assume discovery SUSY, precision from LHC?
Precision from ILC?
Answer depends strongly on underlying NP scenario, many
parameters enter computation of relic density, only a handful of
relevant ones for each scenario – work is going on in North America,
Asia and Europe both for LHC and ILC, within mSUGRA or MSSM
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Moroi, Bambade, Richard, Zhang, Martyn, Tovey, Polesello, Lari, D. Zerwas,
Allanach, Belanger, Boudjema, Pukhov, Battaglia, Birkedal, Gray, Matchev,
Alexander, Fields, Hertz, Jones, Meyraiban, Pivarski, Peskin, Dutta, Kamon,
Arnowitt, Khotilovith, Nojiri…
Precision on relic density
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Concentrate on MSSM, although choice
of case study done within mSUGRA
Examples of typical scenarios
• SPA1A (bulk+coannihilation)
• Coannihilation
• LCC2 (Higgsino or focus)
• Heavy Higgs
One example: SPA1A
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‘Bulk’+ stau
coannihilation
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Annihilation into fermions
Coannihilation with staus
Relevant parameters :
LSP mass, couplings,
slepton masses
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stau-neutralino mass
difference (for coannihilation
processes)
M0=70, M1/2=250, A0=-300,tanβ=10
Determination of parameters
LHC : SPA1A
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Decay chain
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Signal: jet +dilepton pair
Can reconstruct four
masses from endpoint of ll
and qll
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Mixing in the stau
sector obtained from
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For LSP couplings need
3 masses (χ1 χ2 χ4) and
assume tanβ
Assume tanβ known +
limit on heavy stau and
on heavy Higgs
In particular stau-neutralino
mass difference
Here Δm (NLSP-LSP) =
2.5GeV
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LHC: SPA1A
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LHC: roughly the WMAP
precision can be achieved
within MSSM if good
precision on position of ττ
edge
Also important to measure
sfermion/neutralino
parameters and setting
limits on Higgs, other
coannihilation particles…
Nojiri et al, hep-ph/0512204
LHC: SPA1A
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LHC: roughly the WMAP
precision can be achieved
within MSSM if good
precision on position of ττ
edge
Also important to measure
sfermion/neutralino
parameters and setting
limits on Higgs, other
coannihilation particles…
Nojiri et al, hep-ph/0512204
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Even in this favourable scenario, LHC
can reach only roughly WMAP precision
if no underlying assumption about
mSUGRA
Other mSUGRA and even more so other
MSSM scenarios will be hard for LHC
Need ILC precision
• Is that enough?
MSSM: stau coannihilation
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Challenge: measuring precisely
mass difference
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Why? Ωh2 dominated by Boltzmann
factor exp(- ΔM/T)
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Stau-neutralino mass
difference need to be
measured to ~1 GeV
ILC: can match the precision
of WMAP and even better
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Precision required for ΔΩ/Ω~10%
Stau mass at threshold
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Bambade et al, hep-ph/040601
Stau and Slepton masses
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Martyn, hep-ph/0408226
Stau -neutralino mass difference
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Khotilovitch et al, hep-ph/0503165
Allanach et al, JHEP2005
Higgsino in MSSM:
mSUGRA-inspired focus point
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No dependence on mt except
near threshold
Relic density depend on 4
neutralino parameters, M1, M2, ,
tanβ
To achieve WMAP precision on
relic density must determine
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(M1,) 1% .
tanβ~10%
Is it possible?
…. Higgsino LSP
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If squarks are heavy difficult
scenario for LHC
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only gluino accessible,
chargino/neutralino in decays
mass differences could be
measured from neutralino
leptonic decays,
How well can gaugino
parameters can be
reconstructed?
Light Higgsinos possibly many
accessible states at ILC
•Baltz, et al , hep-ph/0602187
… Higgsino LSP
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Recent study of determination
of parameters and
reconstruction of relic density
in this scenario (LCC2)
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LHC: not enough precision
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ILC: chargino pair production
sensitive to bino/Higgsino
mixing parameter
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ILC: roughly 10% precision on
Ωh2
Baltz et al hep-ph/0602187
Annihilation through Higgs
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In mSUGRA relevant
at large tanβ
Important parameters :
mass LSP, mA, Γ(A)
Right at the peak,
annihilation much too
effective
Allanach et al, JHEP2005
Higgs funnel (LCC4)
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Some information on
MA is not sufficient to
have precise prediction
of relic density, must
measure also width
In this scenario
(MA~410GeV), width
can only be measured
at ILC-1000 ( ~10%)
Leads to ΔΩ/Ω~ 18%
M0=380 M1/2=420 tanβ=53
Summary - Relic density
Complementarity astroparticle/
colliders
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Indirect/direct detection can find (some hints from Egret, Hess..) signal for dark
matter
Many experiments under way, more are planned
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Can check if compatible with some SUSY or other scenario
Complementarity with LHC/ILC:
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Establishing that there is dark matter
Probing SUSY dark matter candidates
Models that give good signal in direct/indirect detection (mixed bino/Higgsino
LSP) also give signal at ILC
Direct detection: scattering of LSP on nuclei through Higgs/squark exchange
Indirect detection of product of dark matter pair annihilation in space
(positrons, photons, neutrinos)
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Direct: CDMS, Edelweiss, Dama, Cresst, Zeplin Xenon, Genius…
Indirect: Hess, Veritas, Glast, HEAT, Pamela, AMS, Amanda, Icecube, Antares …
Best signal for hard positrons or hard photons from neutralino annihilation into WW,ZZ
Clear complementarity between (in)direct detection – LHC -ILC
LHC+ILC + indirect detection
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With measurements
from LHC+ILC can we
refine predictions for
direct/indirect detection?
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Consider our Higgsino
example (LCC2)
Prediction for
annihilation crosssection at v=0
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E. Baltz et al hep-ph/0602187
Other dark matter candidates
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Gravitinos (axinos…)
Universal extra-dimensions : LKP
Warped extra-dimensions: LZP
Little Higgs models: LTP
…
Other DM candidates: KK
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UED
• Minimal UED: LKP is B (1), partner of hypercharge
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gauge boson
s-channel annihilation of LKP (gauge boson)
typically more efficient than that of neutralino LSP
Compatibility with WMAP means rather heavy LKP, 500-600
GeV (Tait, Servant)
New calculation show that all coannihilation should be included
as well as radiative corrections to masses (Kong, Matchev)
• Within LHC range, relevant for > TeV linear collider
Other DM candidates: KK
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Warped Xtra-Dim (Randall-Sundrum)
• GUT model with matter in the bulk
• Solving baryon number violation in GUT models
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 stable Kaluza-Klein particle
Example based on SO(10) with Z3 symmetry:
LZP is KK right-handed neutrino
• Agashe, Servant, hep-ph/0403143
Dark matter in Warped X-tra Dim
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Compatibility with WMAP for
LZP range 50- >1TeV
LZP is Dirac particle,
coupling to Z through Z-Z’
mixing and mixing with LH
neutrino
Large cross-sections for
direct detection
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Signal for next generation of
detectors in large area of
parameter space
What can be done at
colliders : identify model,
determination of parameters
and confronting cosmology?
Agashe, Servant, hep-ph/0403143
Other DM candidates: LTP
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Little Higgs models with global symmetry broken at TeV
scale
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light Higgs is a pseudo Nambu-Goldstone boson,
Littlest Higgs model: simplest model but need a discrete
symmetry (T-parity) to be consistent with electroweak
precision measurements
Heavy photon (partner of hypercharge boson) is LTP
Annihilation through Higgs exchange or coannihilation
Determination of parameters at colliders ?
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Precision required on masses expected to be similar to Higgs
funnel scenario of MSSM
Cosmological scenario
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Different cosmological
scenario might affect the
relic density of dark matter
Example: quintessence
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Quintessence contribution
forces universe into faster
expansion
Annihilation rate drops
below expansion rate at
higher temperature
Increase relic density of
WIMPS
In MSSM: can lead to large
enhancements
Profumo, Ullio, hep-ph/0309220
Baryon asymmetry of universe
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Small excess of particles over
antiparticles in the universe
Both Big Bang Nucleosynthesis (BBN)
and measurements of CMB agree
Conditions to create an excess
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Baryon number violation
C and CP violation
Out of thermal equilibrium
Non-vanishing B-L
Need physics Beyond the SM
Electroweak baryogenesis
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Baryon number generation at electroweak phase
transition
Need strong first order phase transition
Finite temperature effective potential
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V= AT2φ2 - ET φ3+ λφ4 , condition : 2E/λ>1
In SM requires Higgs mass < 50 GeV
New physics solution:
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Bosonic loops: light stops in MSSM (Carena et al..)
New strongly coupled fermions
Modification of tree-level potential
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NMSSM, SUSY with U(1)’ (Kang et al, 2005)
Higher-order operators in Higgs-potential
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Kanemura, Okada, Senaha (2004) , Grojean, Servant, Wells (2004)
EW baryogenesis and ILC
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Whether electroweak baryogenesis is realised
with new particles or modification of the Higgs
sector, there will be signals at colliders (and edm)
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Light RH stop in MSSM + light neutralino/
chargino +CP
• Light RH stop for 1st order phase transition
• New CP phases from  and A
• Discovery potential at Tevatron/LHC/ILC + edm
• Signals for CP violation at ILC
• Prediction for relic density of DM in this model
Scenario with light stop
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Can explain both dark
matter and baryon
asymmetry
ILC extend discovery
range of Tevatron
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Freitas et al, Snowmass
Improvement of edm
limit -> strong
constraint on model
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Balazs et al 2005
CP violation and ILC
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CP even observables can be
used to determine phases in
MSSM, unambiguous signal
from CP- and T-odd asymetries
at ILC
Many studies with neutralino/
chargino production and
decays
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T-odd triple product
CP odd asymmetries with
transverse beam polarization
S. Hesselbach, Snowmass
Relic density and phases
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Strong dependence on
phases even after taking
into account shifts in
masses
For example, in stop
coannihilation scenario ~
factor 2
Need to measure
precisely spectrum and
couplings of LSP
(including phases)
GB et al, hep-ph/0604150
Conclusions and remarks
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In most scenarios, LHC will not provide sufficient precise information to
probe cosmology  large uncertainties from particle physics models
remain.
ILC fare much better especially without underlying theoretical
assumption
More detailed studies needed both in MSSM and for other dark matter
candidates
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Note that it might also be possible with collider data to show that
expected relic density is below WMAP pointing towards different
cosmological model or other dark matter candidate
• In this case correlation with signals from direct/indirect
detection important (expect large signals for Higgsino LSP)
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ILC can also test models of baryogenesis
Higgs self-coupling and EWBG
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Electroweak baryogenesis requires a large
correction to the finite temperature effective
potential.
The zero temperature potential is also expected to
receive a large correction.
In particular modification of triple Higgs boson
coupling  can be measured at ILC
For example in 2HDM and MSSM.
S.Kanemura, Y. Okada, E.Senaha, 2004
Triple Higgs coupling at ILC
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Requiring a strong
enough first order
phase transition for
EWBG,
Yasui et al, GLC report
Other DM candidates: gravitino
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Gravitino LSP has extremely weak interactions SUPERWIMP->
irrelevant during thermal freeze-out
NLSP freeze-out as usual (can be slepton, neutralino..) and Ω
can be ~0.1
NLSP eventually decay to SM+gravitino
ΩG = mG/mNLSP ΩNLSP
Relic density naturally of right order
Consequences on BBN or on leptogenesis
Wide range of masses 100GeV-TeV possible for slepton-NLSP
No hope of detecting in direct/indirect detection
Colliders:
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search for metastable NLSP (104-108 s)(trapped in water tanks at
LHC/ILC )
Feng, Smith, hep-ph0409278
MSSM: coannihilation
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Coannihilation
scenario at large tanβ
is more challenging
Strong dependence of
relic density on tanβ
Could be determined
from measurement of
ΓA
M0=213, M1/2=360 tanβ=40
Baltz et al
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With WMAP cosmology has entered precision era, can quantify
amount of dark matter. In 2007 PLANCK satellite will go one step
further (expect to reach precision of 2-3%). This strongly
constrain some of the proposed solutions for cold dark matter
.094 < ΩCDMh2 <.129
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Has triggered many direct/indirect searches for dark matter
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At colliders one can search for the particle proposed as dark
matter candidates
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So far no evidence (LEP-Tevatron) but in 2007 with Large
Hadron Collider (LHC) at CERN will really start to explore a large
number of models and might find a good dark matter candidate