Report

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