Determining Wh2 at the LHC - mSUGRA Co-annihilation Case - Teruki Kamon Collaborators R. Arnowitt, B. Dutta, A. Gurrola, A. Krislock, D. Toback Department of Physics, Texas A&M University NUNPAC Seminar, New Mexico University March 11, 2008 3/11/08 Determining Dark Matter Relic Density at the LHC
Determining Dark Matter Relic Density at the LHC OUTLINE Dark Matter (DM) in Universe DM Particle in SUSY & DM Density (Wh2 ) Cosmological Connection in the mSUGRA Co-annihilation (CA) Region DM Density (Wh2 ) at the LHC Summary 3/11/08 Determining Dark Matter Relic Density at the LHC
Probing the susy Dark Matter The LHC - Accelerator WSUSY DM ≟ WCDM Production & Decay DM ! Detector Talk DM Hunters - Analyzer Today’s 3/11/08 Determining Dark Matter Relic Density at the LHC
Dark Matter Relic Density at the LHC arXiv:0802.2968 (hep-ph) Also see the previous publications: Arnowitt, Arusano, Dutta, Kamon, Kolev, Simeon, Toback, Wagner, PLB 649 (2007) 73 Arnowitt, Dutta, Kamon, Kolev, Toback, PLB 639 (2006) 46 3/11/08 Dark Matter Relic Density at the LHC
Dark Matter (DM) in Universe splitting normal matter and dark matter apart – Another Clear Evidence of Dark Matter – (8/21/06) 1 Ordinary Matter (NASA’s Chandra X Observatory) time 2 3 4 Approximately the same size as the Milky Way Dark Matter (Gravitational Lensing) 3/11/08 Dark Matter Relic Density at the LHC
Dark Matter Relic Density at the LHC DM Particle in SUSY Astrophysics SUSY CDM = Neutralino ( ) SUSY is an interesting class of models to provide a weakly interacting massive neutral particle (M ~ 100 GeV). 3/11/08 Dark Matter Relic Density at the LHC
DM Particle in the SM? I’m hungry. Can you make the DM sandwich with any Standard Model particles? No, sir. But with c10? 3/11/08 Dark Matter Relic Density at the LHC
Determining Dark Matter Relic Density at the LHC DM SANDWICH 3/11/08 Determining Dark Matter Relic Density at the LHC
Co-annihilation (CA) Process Anatomy of sann + …. + + …. Co-annihilation (CA) Process Griest, Seckel ’91 An accidental near degeneracy occurs naturally for light stau in many models. Our benchmark study = mSUGRA 3/11/08 Dark Matter Relic Density at the LHC
+ Minimal Supergravity (mSUGRA) b 4 parameters + 1 sign SUSY model in the framework of unification: <Hd> <Hu> <H> = 246 GeV b + 4 parameters + 1 sign tanb <Hu>/<Hd> at MZ m1/2 Common gaugino mass at MGUT m0 Common scalar mass at MGUT A0 Trilinear couping at MGUT sign(m) Sign of m in W(2) = m Hu Hd Key Experimental Constraints MHiggs > 114 GeV Mchargino > 104 GeV 2.2x10-4 <B(b s g) <4.5x10-4 (g-2)m : 3 s deviation from SM Chamseddine, Arnowitt, Nath, PRL 49 (1982) 970; NPB 227 (1983) 121. Hall, Lykken, Weinberg, PRD 27 (1983) 2359. 3/11/08 Dark Matter Relic Density at the LHC
DM Allowed Regions (Illustration) Mass of Squarks and Sleptons Mass of Gauginos No CDM Candidate Excluded (Magnetic Moment of Muon) (Rare B Decay b sg ) (Higgs mass) CDM allowed region Magnetic Moment of Muon Higgs Mass (Mh) Branching Ratio b sg Co-annihilation Region 3/11/08 Dark Matter Relic Density at the LHC
DM Allowed Regions in mSUGRA Dark Matter Relic Density at the LHC [Focus point region] The lightest neutralino has a larger Higgsino component [A-annihilation funnel region] This appears for large values of m1/2 [Stau-Neutralino CA region] [Bulk region] Almost ruled out … Above is the case of mSUGRA model. However, the results can be generalized. 3/11/08 Dark Matter Relic Density at the LHC
Can we measure DM at colliders? Dark Matter Relic Density at the LHC CA Region at tanb = 40 Can we measure DM at colliders? 3/11/08 Dark Matter Relic Density at the LHC
Smoking Gun of CA Region Dark Matter Relic Density at the LHC Reference Point m1/2 = 350, m0 = 210 tanb = 40, A0 = 0, m >0 [ISAJET version 7.64] SUSY Masses Unique kinematics 97% 100% (CDM) 2 quarks+2 t’s +CDM particle 3/11/08 Dark Matter Relic Density at the LHC
Dark Matter Relic Density at the LHC Most Wanted! This is one of the key reactions to discover the neutralinos at the LHC. We will have to extract this reaction out of many trillion pp collisions and measure SUSY masses. 3/11/08 Dark Matter Relic Density at the LHC
Wc ≟ 0.23 Dark particle hunting [SUSY DM particles at the LHC] ≟ [DM in the Universe] Well, I (a theorist) can calculate the amount of the SUSY dark matter (W) in the Universe (using a model of the Universe). Wc ≟ 0.23 3/11/08 Dark Matter Relic Density at the LHC
Dark Matter Relic Density at the LHC Goals Establish the “CA region” signal Determine SUSY masses and mSUGRA parameters Measure Wch2 and compare with WCDMh2 3/11/08 Dark Matter Relic Density at the LHC
Dark Matter Relic Density at the LHC Analysis Strategy 3/11/08 Dark Matter Relic Density at the LHC
Dark Matter Relic Density at the LHC Excess in ETmiss + Jets Excess in ETmiss + Jets R-parity conserving SUSY Meff Measurement of the SUSY scale at 10-20%. Hinchliffe and Paige, Phys. Rev. D 55 (1997) 5520 ETj1 > 100 GeV, ETj2,3,4 > 50 GeV Meff > 400 GeV (Meff ETj1+ETj2+ETj3+ETj4+ ETmiss) ETmiss > max [100, 0.2 Meff] HM1: High Mass Scenario 1 m1/2= 250, m0= 60; s = 45 fb M(gluino) = 1886; M(squark) = 1721 q The heavy SUSY particle mass is measured by combining the final state particles CMS 3/11/08 Dark Matter Relic Density at the LHC
Dark Matter Relic Density at the LHC Dilepton Endpoint DM content Measurements of the SUSY masses [e.g., M.M. Nojiri, G. Polesselo, D.R. Tovey, JHEP 0603 (2006) 063] Key: Dilepton “edge” in the c20 decay in dilepton (ee, mm, tt) channels for reconstruction of decay chain. LM1: (Low Mass Case 1) m1/2= 180, m0= 850; s = 55 pb [post-WMAP benchmark point B’] M(gluino) = 611 M(squark) = 559 gluino squark+quark B(c20 slepR lep) = 11.2% B(c20 stau1 tau) = 46% B(c1+ sneuL lep) = 36% Spiropoulou (SUSY2007) 3/11/08 Dark Matter Relic Density at the LHC
Dilepton Endpoint in CA Region Dark Matter Relic Density at the LHC In the CA region, the ee and mm channels are almost absent. We are in a different game: Br(c20 eec20, mmc10) ~ 0% Br(c20 ttc10) ~ 100% DM = 5-15 GeV Questions: How can we establish the DM allowed regions? To what accuracy can we calculate the relic density based on the measurements at the LHC? 3/11/08 Dark Matter Relic Density at the LHC
Dark Matter Relic Density at the LHC SUSY Anatomy I 100% 97% SUSY Masses (CDM) M(jtt) M(tt) Meff pT(t) ETmiss + jets + >2t 3/11/08 Dark Matter Relic Density at the LHC
Dark Matter Relic Density at the LHC pTsoft Slope and Mtt pT and Mtt distributions in true di-t pairs from neutralino decay with |h| < 2.5 Number of Counts / 2 GeV Slope of pT distribution of “soft t” contains ΔM information Low energy t’s are an enormous challenge for the detectors ETvis(true) > 20, 20 GeV Number of Counts / 1 GeV ETvis(true) > 40, 20 GeV ETvis(true) > 40, 40 GeV 3/11/08 Dark Matter Relic Density at the LHC
Warming-up Quizzes Hadronic or leptonic? How low in pT? Hadronic, because e or m does not tell us the evidence of tau leptons How low in pT? CDF : pTvis >15-20 GeV Worries about triggers at the LHC? ETmiss + jet trigger for SUSY Lepton+tau trigger for Z’s (calibration) [Assumption] et = 50% , fake rate 1% for pTvis > 20 GeV 3/11/08 Dark Matter Relic Density at the LHC
Dark Matter Relic Density at the LHC 3/11/08 Dark Matter Relic Density at the LHC
Mtt Distribution Clean peak even for low DM We choose the peak position as an observable. 3/11/08 Dark Matter Relic Density at the LHC
Dark Matter Relic Density at the LHC 180 3/11/08 Dark Matter Relic Density at the LHC
Dark Matter Relic Density at the LHC OS-LS Slope(pTsoft ) OS OS-LS Mtt < Mttend point LS pTvis (GeV) 3/11/08 Dark Matter Relic Density at the LHC
Dark Matter Relic Density at the LHC Slope(pTsoft ) vs. X Uncertainty Bands with 10 fb-1 3/11/08 Dark Matter Relic Density at the LHC
Dark Matter Relic Density at the LHC Mtt peak vs. X Uncertainty Bands with 10 fb-1 3/11/08 Dark Matter Relic Density at the LHC
Dark Matter Relic Density at the LHC SUSY Anatomy II 100% 97% SUSY Masses (CDM) Mjtt Mtt Meff pT(t) 3/11/08 Dark Matter Relic Density at the LHC
Mjtt Distribution Mtt < Mttendpoint Jets with ET > 100 GeV Mjtt masses for each jet Choose the 2nd large value Mjtt(2) “other” jet gluinosquark + j Peak value ~ True Value We choose the peak position as an observable. 3/11/08 Dark Matter Relic Density at the LHC
Dark Matter Relic Density at the LHC Mjttpeak vs. X 3/11/08 Dark Matter Relic Density at the LHC
Dark Matter Relic Density at the LHC SUSY Anatomy III 100% 97% SUSY Masses (CDM) Mjtt Mtt Meff pT(t) 3/11/08 Dark Matter Relic Density at the LHC
Dark Matter Relic Density at the LHC Meff Distribution ETj1 > 100 GeV, ETj2,3,4 > 50 GeV [No e’s, m’s with pT > 20 GeV] Meff > 400 GeV (Meff ETj1+ETj2+ETj3+ETj4+ ETmiss [No b jets; eb ~ 50%]) ETmiss > max [100, 0.2 Meff] At Reference Point Meffpeak = 1220 GeV (m1/2 = 335 GeV) Meffpeak = 1331 GeV (m1/2 = 365 GeV) Meffpeak = 1274 GeV 3/11/08 Dark Matter Relic Density at the LHC
Determining SUSY Masses (10 fb-1) 6 equations for 5 SUSY masses 26015 GeV 1s ellipse 10 fb-1 Invert the equations to determine the masses We test a gaugino univesality at 15% level. 3/11/08 Dark Matter Relic Density at the LHC
DM Relic Density in mSUGRA Dark Matter Relic Density at the LHC [1] Established the CA region by detecting low energy t’s (pTvis > 20 GeV) [2] Determined SUSY masses using: Mtt, Slope, Mjtt, Mjt, Meff e.g., Peak(Mtt) = f (Mgluino, Mstau, M , M ) Gaugino universality test at ~15% (10 fb-1) [3] Measure the dark matter relic density by determining m0, m1/2, tanb, and A0 1 c ~ 2 3/11/08 Dark Matter Relic Density at the LHC
Determining mSUGRA Parameters Dark Matter Relic Density at the LHC 3/11/08 Dark Matter Relic Density at the LHC
Dark Matter Relic Density at the LHC Introducing Meff(b) ETj1 > 100 GeV, ETj2,3,4 > 50 GeV [No e’s, m’s with pT > 20 GeV] Meff(b) > 400 GeV (Meff(b) ETj1=b+ETj2+ETj3+ETj4+ ETmiss [j1 = b jet]) ETmiss > max [100, 0.2 Meff] Meff(b)peak = 933 GeV (m1/2 = 335 GeV) Meff(b)peak = 1122 GeV (m1/2 = 365 GeV) At Reference Point Meff(b)peak = 1026 GeV Meff(b)peak Meff(b)peak Meff(b) can be used to determine A0 and tanb even without measuring stop and sbottom masses 3/11/08 Dark Matter Relic Density at the LHC
Mass Measurements mSUGRA Dark Matter Relic Density at the LHC Meff(b)peak & Mttpeak …. Sensitive to A0 and tanb [Meffpeak …. Insensitive to A0 and tanb] 3/11/08 Dark Matter Relic Density at the LHC
Determining mSUGRA Parameters Dark Matter Relic Density at the LHC Solved by inverting the following functions: 10 fb-1 3/11/08 Dark Matter Relic Density at the LHC
Dark Matter Relic Density at the LHC Summary [1] Established the CA region by detecting low energy t’s (pTvis > 20 GeV) [2] Determined SUSY masses using: Mtt, Slope, Mjtt, Mjt, Meff e.g., Peak(Mtt) = f (Mgluino, Mstau, M , M ) Gaugino universality test at ~15% (10 fb-1) [3] Measured the dark matter relic density by determining m0, m1/2, tanb, and A0 using Mjtt, Meff, Mtt, and Meff(b) 1 c ~ 2 3/11/08 Dark Matter Relic Density at the LHC