Transcript Dark matter and the linear collider G. Bélanger LAPTH-Annecy

Dark matter and the linear
collider
G. Bélanger
LAPTH-Annecy
Dark matter : where particle/
astroparticle/ cosmology meet





Dark matter candidates
Cosmology (WMAP) and SUSY dark matter
•
Constraining models
SUSY dark matter at colliders
•
SUSY signal and determination of parameters
Direct/Indirect detection
•
Dark matter signal and complementarity to collider
searches
Other scenarios
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


CMB

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
WMAP- amount of dark matter

The WMAP precise
measurement of the relic
density of dark matter strongly
constrains models of cold dark
matter in particular
supersymmetric models :
.094 < W h2 < .129 (2 sigma)
PLANCK is expecting to reach a
precision of 2-3% (~2007)
Dark matter : cosmo/astro/pp




Universe is made up of 23% DM, what can it be?
•
Cosmology  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
•
•

Weakly interacting new particle
LHC: discovery of new physics, dark matter candidate and/or
new particles
ILC: extend discovery potential of LHC
• Improve on LHC capability of identifying NP model
• More precise determination of model parameters
How well this can be done strongly depends on model for NP
Theoretical ideas


Lots of candidates for cold dark matter
Favourites:
•
•
•

Supersymmetry with R parity conservation
•
•
•
Neutralino LSP
Gravitino
Axino
Kaluza-Klein dark matter
•
•
UED (LKP )
LZP is neutrino-R (in Warped Xdim models with matter in the
bulk)
Little Higgs with T-parity
Will concentrate on the neutralino LSP in different models
Relic density of wimps




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
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


Important processes are those involving particles close in mass to LSP
Public codes to calculate relic density: micrOMEGAs, DarkSUSY
Supersymmetric dark matter

Supersymmetric models with R parity conservation have a good darkmatter
candidate: neutralino LSP

In mSUGRA one must appeal to very specific mechanisms to reach agreement
with WMAP. The main reason
The LSP is mostly bino

A bino LSP annihilates into fermion pairs through
•
t-channel exchange of right-handed slepton

The coupling is U(1) strength  annihilation cross section for neutralino
pairs is not efficient enough  often too much relic density
Need either rather light spectrum (limits from colliders) or fine
adjustment of parameters to meet WMAP

Is this generic of all MSSM models? (here consider only neutralino LSP)
Neutralino LSP

Prediction for relic density depend on parameters of
model
•
•
•
Mass of neutralino LSP
Nature of neutralino : determine the coupling to Z, h, A …
Need some Higgsino component for couplings to Z,W, h, A
•
•
•
M1 <M2< bino
 <M1,M2 Higgsino
M2<M1<  Wino
WMAP – constraining mSUGRA




bino – LSP
•
•
In most of mSUGRA parameter
space
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




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) but in fact what WMAP is telling
us might be rather that a good dark matter candidate is a mixed
bino/Higgsino or mixed bino/wino….
•


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
•
•
•
•
•
mSUGRA –focus point
Non-universal SUGRA
String inspired moduli dominated
Split supersymmetry
NMSSM
Some examples

mSUGRA-focus point
•




Ellis, Baer, Balazs , Belyaev, Olive,
Santoso, Spanos, Nath, Chattopadhyay,
Lahanas, Nanopoulos, Roskowski, Drees,
Djouadi, Tata…
Gaugino fraction
WMAP
fB ~25%
Non universal SUGRA
String inspired: modulidominated
Split SUSY
NMSSM
Feng, hep-ph/0405479
Some examples


mSUGRA-focus
Non universal SUGRA, e.g. non
universal gaugino or scalar masses
•

Binetruy et al, hep-ph/0308047
Higgs exchange
Split SUSY
•
•
•

mixed bino/wino
String inspired moduli-dominated :
generically LSP has important wino
component
•

GB, Boudjema, Cottrant, Pukhov, Bertin,Nezri,
Orloff, Baer, Birkedal-Hansen, Nelson, Mambrino,
Munoz…
M1=1.8M2|GUT
Large M0
Higgsino/wino/bino LSP
Masiero, Profumo, Ullio, hep-ph/0412058
NMSSM
GB, et al, NPB706(2005)
Some examples

mSUGRA-focus
Non universal SUGRA, e.g.
non universal gaugino
masses
String inspired modulidominated :
Split SUSY

NMSSM



•
•
WMAP OK when LSP has
some Higgsino component
Can easily afford smaller
Higgsino fraction because
additionnal channels->
more resonances and
annihilation into->ha
Annihilation->tt
Annihilation->WW
GB, Boudjema, Hugonie, Pukhov, Semenov
hep-ph/0505142
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 (see later)
Corroborating two signals
SUSY dark matter
LHC
•
•
•
Squarks< 2.5 TeV
Gluinos < 2 TeV
Sparticles in decay chains
mSUGRA: probe large
parameter space, heavy Higgs
difficult, large m0-m1/2 also.
Other models : similar reach in
masses
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 (see later)
Corroborating two signals
SUSY dark matter

ILC

Production of any new
sparticles within energy range
Extend the reach of LHC in
particular in “focus point” of
mSUGRA
Precision measurements


Baer et al., hep-ph/0405210
Probing cosmology using collider
information


With LHC data will we be able to tell which scenario?
•
Within the context of a given model can one make precise
predictions for the relic density at the level of WMAP and even
PLANCK (therefore test the underlying cosmological model)
•
•

Colliders cannot discover dark matter but could discover some SUSY
particles, also put lower bounds on masses of undiscovered particles.
Assume discovery SUSY, precision from LHC?
Precision from ILC?
Answer depends strongly on underlying SUSY scenario, many
parameters enter computation of relic density, only a handful of
relevant ones.
The simplest example:
mSUGRA/coannihilation


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
Allanach et al, JHEP 2005
Precision required for 10%
prediction of relic density




Coannihilation with staus
dominant
Coannihilation with
selectrons/smuons also
relevant
Within mSUGRA slepton
masses all related
Precision required on
mSUGRA parameters to
predict Ωh2 at 10% level
•
M0, M1/2 ~2%
Determination of parameters
LHC : bulk+coannihilation






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




Stau-neutralino mass difference
is crucial parameter need to be
measured to ~1 GeV
Assume mSUGRA-like point and
vary stau parameters
independently
LHC: in progress
(LesHouches05)
ILC: can match the precision of
WMAP and sometines better
•
•
Stau mass at threshold
•
Bambade et al, hep-ph/040601
Stau and Slepton masses
•
Martyn, hep-ph/0408226
ILC: slepton masses with small
ΔM

Mass determination from endpoints in energy spectra
• Works better with small
mass difference

Required precision on stauneutralino mass difference can
be reached at ILC (300fb-1)
Martyn, hep-ph/0408226
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


No dependence on mt except
near threshold
To achieve WMAP precision on
relic density must determine
•
•
•

(M1,) 1% .
tanβ~10%
Is it possible?
LHC: difficult when squarks are
heavy, only gluino accessible,
•
•
mass differences could be
measured from neutralino
leptonic decays,
remains to be seen if gaugino
parameters can be
reconstructed (T. Lari, Les
Houches05)
Higgsino LSP : ILC




Light Higgsinos possibly many
accessible states at ILC
Several sizeable cross-sections
Can measure 3 masses with typical
precision 50MeV
Need one additional parameter to
reconstruct all neutralino parameters
•
•

Theoretical assumption: unification of
gaugino masses  precise
determination of Ω at level of WMAP
Use Higgs mass, heavy chargino
production… ->determination of Ω
within factor 2
In MSSM can precision be improved,
detailed study of polarized crosssections, BR and information from LHC
•Moroi, et al , hep-ph/0505252
Complementarity astroparticle
colliders





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…
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
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



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 exchange
Large cross-sections found for
•
•
light squarks
large tanβ, not too heavy “heavy
Higgses” + mixed Higgsino/bino
LSP
Direct detection



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
With next generation of detectors,
direct searches can probe regions
of mSUGRA parameter space
inaccessible to LHC:
•
•

Baer et al. hep-ph/0305191
Present bound
ZEPLIN-MAX
Focus point scenarios (Higgsino)
Some coannihilation region remains
out of reach
Models with mixed Higgsino or wino
have largest cross-sections
GB, Boudjema Cottrant…. NPB706 (2005)
Next generation
Expect
sensitivity 10-9 -10-10pb by 2011
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
Feng et al, hep-ph/0008115
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
Mixed Higgsino or wino: region consistent with relic density will give
“high” detection rate for all indirect detection
In(direct) detection-LHC- LC




Models that give good signal in
direct/indirect detection (non-bino
LSP) can also give signal at ILC
Clear complementarity between
direct detection – LHC -ILC (mixed
Higgsino LSP with heavy squarks
/bino LSP with squarks < 2TeV)
Possibility of signal in both types of
experiments
ILC:
•
•
•
Confirm SUSY signal
Determination of parameters
Combined with LHC, control particle
physics dependence and probe
cosmo/astro
Baer et al, hep-ph/0405210
Other DM candidates: gravitino









Gravitino LSP has extremely weak interactions-> 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:
•
search for metastable NLSP (104-108 s)(trapped in water tanks at
LHC/ILC )
Gravitino LSP




Sample case with stau ~227 GeV
Slepton travel about 10m before
stopping in water
Large number of NLSP’s can be
trapped
High precision study of slepton
decays possible (lifetime, mass)
•
•
•
gravitino mass and SUSY
breaking scale
Calculate precisely relic density
Study late decays relevant for
BBN
Feng, Smith hep-ph/0409278
Other DM candidates: KK

UED
•
•
•

Simplest model: all SM particles propagate in one extra
dimension of size R (TeV-1)
First KK excitation has negative KK parity, is neutral and stable
(LKP) (much like LSP)
Minimal UED: LKP is B (1), partner of hypercharge gauge boson
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 UED

s-channel annihilation of LKP
(gauge boson) typically more
efficient than that of neutralino
•
•


Compatibility with WMAP
means rather heavy LKP
Coannihilation with eR possible
: relic density increases
Within LHC range, relevant for
> TeV linear collider
ILC: need at least 1TeV
•
•
Could distinguish UED from
SUSY (Battaglia et al) by spin
determination
Threshold behaviour for
fermions (β) or scalars (β3)
Dark matter in Warped X-tra Dim



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
Conclusion

If SUSY is correct within a few years good potential for signal
from SUSY AND dark matter – which SUSY model

From precise determination of parameters might have enough
precision to confront cosmological model
•
In general MSSM difficult for the LHC alone

Many other candidates for dark matter …

Complementarity direct/indirect detection and collider searches
to probe models of dark matter

Expect new exciting results soon
Constraining mSUGRA- a word
of warning

Theoretical uncertainties in
mSUGRA predictions for relic
density from uncertainties in
calculation of SUSY spectrum
using RGE’s. At the moment
these uncertainties can reach
up to 10-50%
•
•
Coannihilation: Parameter that
controls Ωh2 is the NLSP-LSP
mass difference (exp –ΔM/T)
Processes with Higgs
exchanges depend strongly on
(MLSP-mh/2)
Ω<.129
Suspect Softsusy, Isajet, Spheno
GB, Kraml, Pukhov, hep-ph/0502079
Non-universal gaugino: wino
Baer et al, hep-ph/0505227
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)
Dark matter in Warped X-tra Dim



Compatibility with WMAP for
LZP range 50- >1TeV
LZP is Dirac fermion,
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
Wino LSP

Both direct and
indirect detection
rates are enhanced
for wino LSP
Baer et al hep-ph/0505227
Focus point – annihilation of
neutralinos

Annihilation into gauge
bosons pairs are
enhanced in focus-point
region (mixed Higgsino
LSP)

Region consistent with
relic density will give
“high” detection rate for
all indirect detection