1Bhaskar DuttaTexas A&M UniversityDark Matterat Colliders06/15/11PPC 20112We are about to enter into an era of major discoveryDark Matter: we need new particles to explain the content of the universeStandard Model: we need new physics Supersymmetry solves both problems! Future results from PLANCK, direct and indirect detection, rare decays etc. experiments in tandem with the LHC will confirm a modelLHC: directly probes TeV scaleDiscovery Time…The super-partners are distributed around 100 GeV to a few TeVThis talk: Can we establish SUSY models at the LHC? How accurately we can calculate dark matter density?3The signal : jets + leptons+ t’s +W’s+Z’s+H’s + missing ETSUSY at the LHC(or l+l-, t+t-)DMDMColored particles are produced and they decay finally into the weakly interacting stable particleHigh PTjetHigh PTjet[mass difference is large]The pT of jets and leptonsdepend on the sparticle masses which are given by modelsR-parity conserving(or l+l-, t+t-)Wang’s talk [morning]SUSY at the LHC Dilemma...4SUSY at the LHC Dilemma...56SUSY at the LHCFinal states  Model Parameters  Calculate dark matter density We may not be able to solve for masses of all the sparticles from a model Reconstruct sparticle masses, e.g., Solving for the MSSM : Very difficult01~~++ lqQ01~~+ lL0104,3,2~,,~+ llhZetc.Identifying one sideis very tricky!7SUSY at the LHCThe best strategy:Solve for the minimal model: mSUGRA/CMSSM 4 parameters + sign: m0, m1/2, A0, tanb and Sign(m) The cascades can be understood in a simpler way [hopefully!]Next step:Models with more parameters, e.g.,Next to minimal model (Higgs non-universality), Gaugino Non-universality (Mirage Mediation model) etc…We can use simpler models to understand the cascades and solve for the model parametersCalculate the Dark Matter content8mSUGRA Parameter spaceAllahverdi, Dutta, SantosoPLB 687:225 ,2010 Coannihilation RegionFocus point• The bounds from CDMS/Xenon 100 have started becoming competitive with b s g and Higgs mass constraints(warning: Nuclear Matrix element etc) .92GeV) 37(21/2150202cE++ m.m~mIn mSUGRA model the lightest stau seems to be naturally close tothe lightest neutralino mass especially for large tanbFor example, the lightest selectron mass is related to the lightestneutralino mass in terms of GUT scale parameters:For larger m1/2the degeneracy ismaintained by increasing m0andwe get a corridor in the m0- m1/2plane.The coannihilation channeloccurs in most SUGRAmodels even with non-universal soft breaking.21/2160201m.~m Thus for m0 = 0, becomes degenerate with at m1/2 = 370 GeV, i.e. the coannihilation region begins at01~2cE~m1/2 = (370-400) GeV1. Coannihilation, GUT ScaleArnowitt, Dutta, Santoso’ 01910Smoking Gun of CA Region1t~ttLu~01χ~02χ~g~uuSUSY Masses(CDM)2 quarks+2 t’s+missing energy10Low energy taus characterize the CA regionHowever, one needs to measure the model parameters to predict thedark matter content in this scenarioTypical decay chain and final states at the LHCJets + t’s+ missing energy11CA Region: Final Statest= 50%, ffake= 1% for pTvis> 20 GeVMjtt&MjtLu~01χ~02χ~g~uuSUSY Masses(CDM)Mtt& pT(t)1t~ttExcesses in 3 Final States:a)ETmiss+ 4jb)ETmiss+ 2j+2tc)ETmiss+ b +3jExample of Analysis Chart for b):KinematicalvariablesSUSY at the LHC Dilemma...12SUSY at the LHC Dilemma...13OS-LS Subtraction14Extracting One side: jttOS-LS selection of ditaus selects , but if we need to reconstruct the entire side 02χ~We use the following subtraction scheme:2tBi Event Subtraction technique: BESTBEST and SUSY Dilemma…15BEST16arXiv:1104.2508 [hep-ph]Dutta, Kamon, Kolev, Krislock,What BEST Looks Like...17Top reconstruction : BEST18End Point Techniques with BEST19Significance improves 5 times with BEST[1] Established the CA region by detectinglow energyt’s (pTvis> 20 GeV)[2] Measured 5 SUSY masses(DM, , , , ) fromDM Relic Density in mSUGRA),tan,,(),(),tan,,(),(002/14peakbeff,02/13peakeff002/12peak02/11peakAmmXMmmXMAmmXMmmXMjbbtttt),tan,(02/102~01AmmZhb[3] Determine the dark matter relic densityby determining m0, m1/2, tanb, and A0202001~02~q~g~21Determining mSUGRA ParametersSolved by inverting the following functions:140tan1604350521002/10bAmm),tan,(02/102~01AmmZhb1fb 10-L1fb 50-)fb 70( %1.4)fb 30( %2.6/112~2~0101-- hh),tan,,(),(),tan,,(),(002/14peak )(eff02/13peakeff002/12peak02/11peakAmmXMmmXMAmmXMmmXMbjbbtttt10 fb-12121)fb 30( %7/1~~0101---pp22ILC analysis: 500 GeV40tan035021002/10bAmm1.10.15.9+-DMArnowitt, Dutta, Kamon; PLB 05LHCWe need 50fb-1(500 fb-1)This result was used in Baltz, Battaglia, Peskin, Wizansky’ 05 to extract relic density by usingILC and LHC(LCC3 point)’05We can determine DM at the LHC,Arnowitt, Dutta, Kamon et al,PRL 08Comparison23GUT Scale SymmetryWe can probe the physics at the Grand unifiedtheory (GUT) scaleThe masses , , unify at the grand unified scale in the mSUGRA model01~m1/2massMZMGUTLog[Q]g~01~02~02~g~Gaugino universality test at ~15% (10 fb-1)Another evidence of a symmetry at the grand unifying scale!Use the masses measured at the LHC and evolve them to the GUT scale using mSUGRAMirage mediation models can be discerned242. Over-dense DM RegionSmoking gun signals in the region?A0= 0, tanb= 40m1/2m02424Dilaton effect creates new parameter spaceLahanas, Mavromatos, Nanopoulos, PLB649:83-90,2007.25m1/2= 440 GeV; m0 = 471 GeVm1/2= 600 GeV; m0 = 440 GeV86.8%77.0%2 Reference Points252526Case 2(a) : Higgs1t~Lu~01χ~02χ~g~h1χ~m1/2=440, m0=471, tanb=40, mtop=175Re~u10411044500393181341114462Z91N(b) > 2 with PT> 100 GeV; 0.4< DRbb< 1ETmiss> 180 GeV; N(jet) > 2 with ET> 200 GeV; ETmiss+ ETj1+ ETj2> 600 GeVETmiss> 180 GeV; N(jet) > 2 with ET> 200 GeV; ETmiss+ ETj1+ ETj2> 600 GeV262627Determining h2Solved by inverting the following functions:1839tan95015440504720210bAmm/),tan,(02/102~01AmmZhb1fb 1000-L%~h/h~~150ΩΩ220101)tan()tan()()(00214peak )(eff00213peak )(eff0212peakeff0211point endA,,m,mXMA,,m,mXMm,mXMm,mXM/bb/b//jbbbb1000 fb-12727Dutta, Gurrola, Kamon, Krislock , Nanopoulos, Lahanas, Mavromatos, PRD 0928Case 3 : Focus Point/Hyperbolic BranchProspects at the LHC:A few mass measurementsare available: 2ndand 3rdneutralinos, and gluinoCan we determine thedark