1. G. Bélanger LAPTH- Annecy
Cosmology and the ILC
G. Bélanger
LAPTH- Annecy

2. PLAN Neutralino dark matter Cosmology <-> colliders
Baryon asymmetry
Dark energy?
Neutralino dark matter
Precision studies
Correlation with direct/indirect detection
Dark matter : beyond MSSM
Electroweak Baryogenesis
Conclusions

3. What is the universe made of?
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 with CMB anisotropy map achieve precise determination of cosmological parameters

4. 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
Dark matter: 23+/- 4%
Baryons: 4+/-.4%
Dark energy 73+/-4%
Neutrinos < 1%

5. Search for dark matter
In 2003 WMAP has measured relic density +/-15% (2σ)
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

6. What is dark matter/dark energy
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
Related to Planck scale physics
NP for dark energy might affect cosmology and dark matter
Neutrinos (they exist but only small component of DM)
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)
Branons
Little Higgs with T-parity ……

7. 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

8. Relic density
A relic density in agreement with present measurements Ωh2 ~0.1 requires typical weak interactions cross-section

9. Accuracy on relic density of LSP
Goal is to reach at least the same precision on the prediction of the relic density as the experimental one +X
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
Changes in H affect the freeze-out temperature
New terms in Boltzmann equations

10. Dark matter : cosmo/astro/pp
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
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

11. 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 …
M1 <M2< bino
 <M1,M2 Higgsino
M2<M1<  Wino

12. Neutralino annihilation
3 typical mechanisms for χ annihilation
Bino annihilation into ff
σ ~ mχ2/mf 4
Mixed bino-Higgsino (wino)
Coupling depends on Z12,Z13,Z14, mixing of LSP
Annihilation near resonance (Higgs)

13. Neutralino annihilation
3 typical mechanisms for χ annihilation
Bino annihilation into ff
σ ~ mχ2/mf 4
Mixed bino-Higgsino (wino)
Coupling depends on Z12,Z13,Z14
Annihilation near resonance (Higgs)
Need some coupling to A, some mixing with Higgsino

14. 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
Important processes are those involving particles close in mass to LSP
Public codes to calculate relic density: micrOMEGAs, DarkSUSY, IsaRED
Exp(- ΔM)/T

15. Neutralino co-annihilation
Can occur with all sfermions, gauginos
Bino LSP (sfermion coannihilation)
Higgsino LSP- coannihilation with chargino and neutralinos

16. 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)

17. The mSUGRA case
Mt=178
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
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=175GeV

18. The mSUGRA case -WMAP 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)

19. WMAP and SUSY dark matter
The mSUGRA model seems fine-tuned (either small ΔM or Higgs resonance) .
The LSP is bino
Not generic of other SUSY models, a good dark matter candidate is a mixed bino/Higgsino ….
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….

20. 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
Squarks, gluinos < 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/

21. 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(10-15%) and even PLANCK (3-6%) (2007) therefore test the underlying cosmological model.
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
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…

22. Precision on relic density
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

23. One example: SPA1A ‘Bulk’+ stau coannihilation
M0=70, M1/2=250, A0=-300,tanβ=10
‘Bulk’+ stau coannihilation
Annihilation into fermions
Coannihilation with staus
Relevant parameters : LSP mass, couplings, slepton masses
stau-neutralino mass difference (for coannihilation processes)

24. Determination of parameters LHC : SPA1A
Decay chain
Signal: jet +dilepton pair
Can reconstruct four masses from endpoint of ll and qll
In particular stau-neutralino mass difference
Here Δm (NLSP-LSP) = 2.5GeV
Mixing in the stau sector obtained from
For LSP couplings need 3 masses (χ1 χ2 χ4) and assume tanβ
Assume tanβ known + limit on heavy stau and on heavy Higgs

25. LHC: SPA1A
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/

26. LHC: SPA1A
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/

27. 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?

28. MSSM: stau coannihilation
Challenge: measuring precisely mass difference
Why? Ωh2 dominated by Boltzmann factor exp(- ΔM/T)
Stau-neutralino mass difference need to be measured to ~1 GeV
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/
Stau -neutralino mass difference
Khotilovitch et al, hep-ph/
Precision required for ΔΩ/Ω~10%
Allanach et al, JHEP2005

29. Higgsino in MSSM: mSUGRA-inspired focus point
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?

30. …. Higgsino LSP If squarks are heavy difficult scenario for LHC
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/

31. … Higgsino LSP
Recent study of determination of parameters and reconstruction of relic density in this scenario (LCC2)
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/

32. Annihilation through Higgs
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

33. Higgs funnel (LCC4)
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

34. Summary - Relic density

35. 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
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)
Best signal for hard positrons or hard photons from neutralino annihilation into WW,ZZ
Clear complementarity between (in)direct detection – LHC -ILC

36. LHC+ILC + indirect detection
With measurements from LHC+ILC can we refine predictions for direct/indirect detection?
Consider our Higgsino example (LCC2)
Prediction for annihilation cross-section at v=0
E. Baltz et al hep-ph/

37. Other dark matter candidates
Gravitinos (axinos…)
Universal extra-dimensions : LKP
Warped extra-dimensions: LZP
Little Higgs models: LTP …

38. 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 LSP
Compatibility with WMAP means rather heavy LKP, 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

39. Other DM candidates: KK
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 right-handed neutrino
Agashe, Servant, hep-ph/

40. 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/

41. Other DM candidates: LTP
Little Higgs models with global symmetry broken at TeV scale
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 ?
Precision required on masses expected to be similar to Higgs funnel scenario of MSSM

42. 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/

43. Baryon asymmetry of universe
Small excess of particles over antiparticles in the universe
Both Big Bang Nucleosynthesis (BBN) and measurements of CMB agree
Conditions to create an excess
Baryon number violation
C and CP violation
Out of thermal equilibrium
Non-vanishing B-L
Need physics Beyond the SM

44. Electroweak baryogenesis
Baryon number generation at electroweak phase transition
Need strong first order phase transition
Finite temperature effective potential
V= AT2φ2 - ET φ3+ λφ4 , condition : 2E/λ>1
In SM requires Higgs mass < 50 GeV
New physics solution:
Bosonic loops: light stops in MSSM (Carena et al..)
New strongly coupled fermions
Modification of tree-level potential
NMSSM, SUSY with U(1)’ (Kang et al, 2005)
Higher-order operators in Higgs-potential
Kanemura, Okada, Senaha (2004) , Grojean, Servant, Wells (2004)

45. EW baryogenesis and ILC
Whether electroweak baryogenesis is realised with new particles or modification of the Higgs sector, there will be signals at colliders (and edm)
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

46. Scenario with light stop
Can explain both dark matter and baryon asymmetry
ILC extend discovery range of Tevatron
Freitas et al, Snowmass
Improvement of edm limit -> strong constraint on model
Balazs et al 2005

47. CP violation and ILC
S. Hesselbach, Snowmass
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
T-odd triple product
CP odd asymmetries with transverse beam polarization

48. Relic density and phases
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/

49. Conclusions and remarks
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
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)
ILC can also test models of baryogenesis

50. Higgs self-coupling and EWBG
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

51. Triple Higgs coupling at ILC
Requiring a strong enough first order phase transition for EWBG,
Yasui et al, GLC report

52. Other DM candidates: gravitino
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:
search for metastable NLSP ( s)(trapped in water tanks at LHC/ILC )
Feng, Smith, hep-ph

53. MSSM: coannihilation
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

54. 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
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
.094 < ΩCDMh2 <.129