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Supersymmetric dark matter:
implications for colliders and
astroparticle
G. Bélanger
LAPTH-Annecy
PLAN

Evidence for dark matter
Cosmology and SUSY dark matter

SUSY dark matter at colliders
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• Constraining models
•
SUSY signal and determination of parameters
Direct/Indirect detection
• DM signal and complementarity to collider
searches

Final remarks
Evidence for dark matter

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Most of the matter in the universe cannot be detected from
the light emitted (dark matter)
Presence of dark matter is inferred from motion of
astronomical objects
•
•

If we measure velocities in some region there has to be enough
mass for gravity to hold objects together
The amount of mass needed is more than luminous mass
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•
The galactic scale
Scale of galaxy clusters
Dark matter is required to amplify the small fluctuations in
Cosmic Microwave background to form the large scale
structure in the universe today
•
Cosmological scales
Evidence for dark matter:
Rotation curves of galaxies

Negligible luminosity in galaxy
halos, occasional orbiting gas
clouds allow measurement of
rotation velocities and distances

Newton

r> rluminous,
M(r) =constant
v should decrease
Observations of many galaxies:
rotation velocity does not
decrease
Dark matter halo would provide
with M(r)~r v-> constant
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Galaxy clusters

1933: Zwicky got first evidence of dark matter
in galaxy clusters

Confirmed by many observations on galaxy
clusters
•
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Determine total mass required to provide self-gravity
necessary to stop system from flying apart
Mass/Light ratio 200-300 (two orders of magnitude
more than in solar system)
Cosmic microwave background
and total amount of dark matter in the universe

Background radiation originating from
propagation of photons in early universe
(once they decoupled from matter)
predicted by Gamow in 1948

Discovered Penzias&Wilson 1965

CMB is isotropic at 10-5 level and follows
spectrum of a blackbody with T=2.726K

Anisotropy to CMB tell the magnitude and
distance scale of density fluctuation when
universe was 1/1000 of present scale

Study of CMB anisotropies provide
accurate testing of cosmological models,
puts stringent constraints on cosmological
parameters
Cosmic microwave background
CMB – density fluctuations

CMB anisotropy maps
•
Precision determination of
cosmological parameters

All information contained in
CMB maps can be
compressed in power
spectrum

To extract information :
start from cosmological
model with small number
of parameters and find
best fit
What is the universe made of?


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%

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

Has triggered many direct/indirect searches for dark matter

At colliders one can search for the particle proposed as dark
matter candidates

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
What is dark matter/dark energy

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
•
•
•
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
Wimpzillas, Q-balls, cryptons…
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

Relic density

A relic density in agreement with present
measurements Ωh2 ~0.1 requires typical
weak interactions cross-section
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
•
Direct/Indirect detection : search for dark matter  establish
that new particle is dark matter  constrain models
Colliders : which model for NP/ confront cosmology
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•
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Generic class of SUSY models that are OK
LHC: discovery of new physics, dark matter candidate and/or
new particles
ILC: extend discovery potential of LHC
How well this can be done strongly depends on model for NP
Supersymmetry

Motivation: unifying matter (fermions) and interactions
(mediated by bosons)
•

Prediction: new particles supersymmetric partners of all
known fermions and bosons
•
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
Symmetry that relates fermions and bosons
Not discovered yet
Hierarchy problem
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Electroweak scale (100GeV) << Planck scale
SUSY particles (~TeV) to stabilize Higgs mass against radiative
corrections should be within reach of LHC
Unification of couplings
Evidence for supersymmetry?



Coupling constants “run” with
energy
Precise measurements of
coupling constants of Standard
Model SU(3),SU(2), U(1) at
electroweak scale (e.g. LEP)
indicate that they do not unify at
high scale (GUT scale)
SM coupling constants unify
within MSSM
Minimal Supersymmetric Standard Model

Minimal field content:
partner to SM particles
(also need two Higgs
doublets)

Neutralinos: neutral spin ½
partners of gauge bosons
(Bino, Wino) and Higgs
scalars (Higgsinos)
R-parity


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Proton decay
To prevent this introduce R parity
•
R=(-1) 3B-3L+2S; R=1: SM particles R=-1 SUSY
The LSP is stable
Neutralino LSP

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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•
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M1 <M2< bino
 <M1,M2 Higgsino
M2<M1<  Wino
Neutralino annihilation

3 typical mechanisms for
χ annihilation
•
Bino annihilation into ff
•
Mixed bino-Higgsino (wino)
•
• σ ~ mχ2/mf 4
• Coupling depends on
Z12,Z13,Z14, mixing of LSP
Annihilation near resonance
(Higgs)
Neutralino annihilation

3 typical mechanisms for
χ annihilation
•
Bino annihilation into ff
•
Mixed bino-Higgsino (wino)
•
• σ ~ mχ2/mf 4
• Coupling depends on
Z12,Z13,Z14
Annihilation near resonance
(Higgs)
• Need some coupling to A,
some mixing with Higgsino
Coannihilation

If M(NLSP)~M(LSP) then
maintains thermal
equilibrium between NLSP-LSP even after SUSY particles decouple from
standard ones

Relic density depends on rate for all processes involving LSP/NLSP  SM

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

Can occur with all
sfermions, gauginos
•
•
Bino LSP (sfermion
coannihilation)
Higgsino LSPcoannihilation with
chargino and
neutralinos

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)
WMAP constraining NP:
mSUGRA example
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bino – LSP
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•
•
In most of mSUGRA parameter
space
Annihilation in fermion pairs
Works well for light sparticles
but hard to reconcile with
LEP/Higgs limit (small window
open)
Sfermion coannihilation
•
•
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
WMAP – constraining mSUGRA
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Bino – LSP
Sfermion Coannihilation
Mixed Bino-Higgsino
•
•
Annihilation into W pairs
In mSUGRA unstable region, mt
dependence, works better at
large tanβ
Resonance (Z, light/heavy
Higgs)
•
•
LEP constraints for light Higgs/Z
Heavy Higgs at large tanβ
(enhanced Hbb vertex)
WMAP and SUSY dark matter

In mSUGRA might conclude that the model is fine-tuned
(either small ΔM or Higgs resonance) .
•
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Not generic of other SUSY models, in fact what WMAP is
telling us might be that a good dark matter candidate is a
mixed bino/Higgsino or mixed bino/wino….
•
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The LSP is mostly bino
In particular, main annihilation into gauge boson pairs works well
for Higgsino (or wino) fraction ~25%
What does that tell us about models?
Some examples
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mSUGRA-focus point
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Gaugino fraction
Ellis, Baer, Balazs , Belyaev, Olive,
Santoso, Spanos, Nath, Chattopadhyay,
Lahanas, Nanopoulos, Roskowski, Drees,
Djouadi, Tata…
Non universal SUGRA
String inspired: modulidominated
Split SUSY
NMSSM
Feng, hep-ph/0405479
Some examples
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mSUGRA-focus point
•
M1=1.8M2|GUT
Ellis, Baer, Balazs , Belyaev, Olive, Santoso, Spanos,
Nath, Chattopadhyay, Lahanas, Nanopoulos,
Roskowski, Drees, Djouadi, Tata…
Non universal SUGRA, e.g. non
universal gaugino or scalar masses
• GB, Boudjema, Cottrant, Pukhov, Bertin,Nezri,
mixed bino/wino
Orloff, Baer, Belyaev, Birkedal-Hansen, Nelson,
Mambrini, Munoz…
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String inspired moduli-dominated :
LSP has important wino component
• Binetruy et al, hep-ph/0308047
Split SUSY : Large M0, LSP is mixed
Higgs exchange
Higgsino/wino/bino

• Masiero, Profumo, Ullio, hep-ph/0412058
NMSSM
• GB, Boudjema, Hugonie, Pukhov, Semenov
GB, et al, NPB706(2005)
PLAN

Evidence for dark matter
Cosmology and SUSY dark matter

SUSY dark matter at colliders


• Constraining models
•
SUSY signal and determination of parameters
Direct/Indirect detection
• Dark matter signal and complementarity to
collider searches

Final remarks
Which scenario? Potential for
SUSY discovery at LHC/ILC

Some of these scenarios will be probed at
LHC/ILC and/or direct /indirect detection
experiments

Corroborating two signals SUSY dark
matter
LHC
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•
•
•
•
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Squarks, gluinos < 2- 2.5 TeV
Sparticles in decay chains
mSUGRA: probe significant parameter
space, heavy Higgs difficult, large m0-m1/2
also.
Other models : similar reach in masses
ILC
•
•
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

Within the context of a given model can one make precise predictions
for the relic density at the level of WMAP(10%) and even PLANCK
(3%) (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
•
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…
The simplest example:
mSUGRA/coannihilation (staus)

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Challenge: measuring
precisely mass difference
Why? Ωh2 dominated by
Boltzmann factor exp(- ΔM/T)
•

Although masses are predicted at
1-2% level, still leads to large
uncertainties in relic density
Precision required on
mSUGRA parameters to
predict Ωh2 at 10% level
•

Allanach et al, JHEP 2005
M0, M1/2 ~2%
LHC: roughly this precision can
be achieved in “bulk” region
•
Tovey, Polesello, hep-ph/0403047

For coannihilation region errors
on mass could be larger (more
difficult with staus
Determination of parameters
LHC : bulk+coannihilation
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Decay chain
M0=100, M1/2=250, tanβ=10
Signal: jet +dilepton pair
Can reconstruct four masses
from endpoint of ll and qll
Global fit to model parameters
For this particular point,
ΔM0~2%, ΔM1/2~0.6% -->
ΔΩ/Ω~3%
For WMAP compatible point
this precision will be barely
sufficient for ΔΩ/Ω~10% and
errors on masses could be
larger (more difficult with
staus)
Tovey, Polesello, hep-ph/0403047
MSSM: coannihilation
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Stau-neutralino mass difference
is crucial parameter need to be
measured to ~1 GeV
LHC: in progress
ILC: can match the precision of
WMAP and even better
•
•
•
Stau mass at threshold
•
Bambade et al, hep-ph/040601
Stau and Slepton masses
•
Martyn, hep-ph/0408226
Stau -neutralino mass difference
(~1GeV)
•
Khotilovitch et al, hep-ph/0503165
Allanach et al, JHEP2005
Another example: Focus (Higgsino
LSP)

In mSUGRA at large M0, 
decrease rapidly, the LSP has
large Higgsino component
•
•
Annihilation into W pairs
Neutralino/chargino NLSP:
gaugino coannihilation

With ~25-40% Higgsino  just
enough dark matter

Within mSUGRA strong
dependence on SM input
parameters (mt): no reliable
prediction of the relic density
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
•
•
•
(M1,) 1% .
tanβ~10%
Is it possible?
…. Higgsino LSP

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

Recent study of determination
of parameters and
reconstruction of relic density
in this scenario

LHC: not enough precision

ILC: chargino pair production
sensitive to bino/Higgsino
mixing parameter

ILC: roughly 10% precision on
Ωh2
Baltz et al hep-ph/0602187
Colliders and relic density

For neutralino LSP, in favourable scenarios LHC will give
precise information on the parameters of MSSM and this
will allow to refine the predictions for relic density of
neutralinos.

In other scenarios, will have to wait for ILC @TeV

What about precise predictions for direct/indirect
detection?
Direct/indirect detection

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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
•
•
Direct: CDMS, Edelweiss, Dama, Cresst, Zeplin Xenon, Genius, Picasso…
Indirect: Hess, Veritas, Glast, HEAT, Pamela, AMS, Amanda, Icecube,
Antares …
Can check if compatible with some SUSY or other scenario
Complementarity with LHC/ILC:
•
•
•
Establishing that there is dark matter
Probing SUSY dark matter candidates
LHC: good signal if light squarks/gluinos, direct/indirect detection good
signal for (mixed bino/Higgsino LSP)
Assuming some signals are discovered: corroborating
information from colliders/astroparticle
• Also tests of assumptions about dark matter distribution in
the halo…
Direct detection of dark matter
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
Detect dark matter through
interaction with nuclei in large
detector.
Depends on local density and
velocity distribution of dark
matter
Dependence on coupling of LSP
to quarks and gluons
• s-channel squark exchange
• t-channel Higgs (Z)
exchange
Large cross-sections found for
• light squarks
• large tanβ, not too heavy
“heavy Higgses” + mixed
Higgsino/bino LSP
Direct detection of dark matter


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Typical LSP-proton scalar crosssections range from 10-10 pb in
coannihilation region to 10-8-10-6 pb in
focus point region of mSUGRA
Present detector (including DAMA) not
sensitive enough to probe mSUGRA
Present bound
With next generation of detectors,
direct searches can probe regions
of mSUGRA parameter space
inaccessible to LHC
•
•

Baer et al. hep-ph/0305191
ZEPLIN-MAX
Focus point scenarios (large m0)
especially at large tan().
Some coannihilation region remains out
of reach
Models with mixed Higgsino or wino
have largest cross-sections
Next generation
Expect
sensitivity 10-9 -10-10pb by 2011
Direct detection: non-universal
models

In models where LSP is
not pure bino: good
prospect for direct
detection even if squarks
heavy
•
•
Example: model with nonuniversal gaugino mass
Models with heavy Higgs
out of reach of even tonscale detectors
GB, Boudjema, Cottrant, Pukhov, Semenov, NPB706(2005)
Indirect detection

Pair of dark matter particles
annihilate and their annihilation
products are detected in space
•
•
•

Positrons from neutralino
annihilation in the galactic halo
Photons from neutralino
annihilation in center of galaxy
Neutrinos from neutralino in sun
mSUGRA
Positrons from AMS
Best signal for hard positrons or
hard photons from neutralino
annihilation ->WW,ZZ
•
•
Favoured for mixed
bino/Higgsino or bino/wino
Hard Photons also from
annihilation of neutralino pair in
photons (loop suppressed)
Photons from GLAST
LHC + direct detection

With measurements from
LHC can we refine
predictions for
direct/indirect detection?

Consider our first example:

•
M0=100, M1/2=250 A0=-100
Prediction for spindependent cross-section
E. Baltz et al hep-ph/0602187
Final remarks
Other DM candidates: KK


UED
•
•
•
•
Minimal UED: LKP is B (1), partner of hypercharge gauge boson
s-channel annihilation of LKP (gauge boson) typically more
efficient than that of neutralino
Compatibility with WMAP means rather heavy LKP
Within LHC range, relevant for > TeV linear collider
Warped Xtra-Dim (Randall-Sundrum)
•
•
•
GUT model with matter in the bulk
Solving baryon number violation in GUT models  stable
Kaluza-Klein particle
Example based on SO(10) with Z3 symmetry: LZP is KK righthanded neutrino
•
Agashe, Servant, hep-ph/0403143
Dark matter in Warped X-tra Dim
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
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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
•

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
Cosmological scenario


Different cosmological
scenario might affect the
relic density of dark matter
Example: quintessence
•
•
•
•
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
Conclusions

Cosmology provides accurate determination of
properties of dark matter


LHC has good opportunities to discover new physics
In some favourable scenarios LHC might be able to
make precise enough measurement to give accurate
prediction of relic density of dark matter –confront
cosmology
Complementarity astroparticle/colliders

Expect lots exciting results soon
