Randall Sundrum KK Graviton at CMS Caroline Collard, LLR, Ecole Polytechnique, France Work in collaboration with M.-C. Lemaire, P. Traczyk and G. Wrochna Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders Overview Extra Dimensions & Randall Sundrum Model Search for RS graviton in the CMS detector The CMS detector Signal & Background First Analysis: 5  discovery limit The photon radiation with PHOTOS If no signal? 95% CL signal exclusion If a signal? Spin-2 analysis Conclusions Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders Extra Dimensions Why? Unification of gravitation with other forces. Hierarchy problem : MEW and MPL Different models of ED Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders Warped ED The Randall-Sundrum Model: only one extra dimension  5D Anti-de-Sitter Spacetime metric: e-2kr  dx dx + r2 d2 k (~ MPL): AdS5 curvature, r: compactification radius, r : new coordinate and x: traditional 4D coordinates Gravity Scale: =MPL e-kr no hierarchy if kr≈12 SM brane Planck brane bulk r  r  = 0 r  = r  Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders Warped ED The Randall-Sundrum Model: Two parameters in the model: e-kr and k/MPL Graviton in 5D  KK graviton excitations in 4D Experimental measurement of the 1st KK graviton M1 [Mn = k xn e-kr with J1(xn)=0] 1 [n =  Mn xn2 (k/MPL)2 with (open decay mode)] Other parameter choice: M1 and c= k/MPL c is related to 1 and also to the coupling Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders Variation of c 0.01 ≤ c ≤ 0.1 c = 0.1 c = 0.05 c = 0.02 c = 0.01 d/dM MG Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders The CMS detector pp collider: 14 TeV in cms Start in 2007 1 year @ low lumi: 10 fb-1 1 year @ high lumi: 100 fb-1 Higgs Discovery and Search for New Physics Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders Analysis Signal: ffbar, gg  G   (B.R.= 4 %) ffbar, gg  G  e+e-, +- (B.R.= 2 %) Generation with PYTHIA Photon Radiation with PYTHIA or PHOTOS Detector response with CMSJET (Fast Simulation) Exotic Signals at Hadron Colliders 26/02/03

CMS Performance in CMSJET ECAL: For electron and  detection Barrel (||<1.56)  E/E = 3% /√E + 0.2/E + 0.55% Endcap (1.65<| |< 3)  E/E = 6% /√E + 0.9/E + 0.55% Tracker: For muon detection p/p = 4% √p Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders Analysis CMSJET Backgrounds: For  : ffbar, gg   (+ photon-jet: ffbar  g, fg f, gg  g + dijet: ff  ff, ffbar  ffbar, ffbar  gg, fg  fg, gg  ffbar, gg  gg) No K factor for . For e+e-, +-: pp  Z/  l+l- (Drell Yan) K factor =1.38 from comparison between PYTHIA MC and CDF data # Events M (GeV) Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders MG= 1500 GeV, c=0.01, Lumi=100 fb-1 CMSJET G   # Events M (GeV) Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders 5  Discovery Limit CMSJET 100 fb-1 G   c =0.01 .B (fb) MG (GeV) Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders MG= 1000 GeV, c=0.01, Lumi=100 fb-1 CMSJET Difference in resolution for e (Energy in calo) and  (Momentum in tracker) => Different mass windows Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders 5  Discovery Limit CMSJET G  e+e- c =0.01 .B (fb) MG (GeV) Exotic Signals at Hadron Colliders 26/02/03

 Radiation with PHOTOS Use of PHOTOS to generate  radiation, in place of PYTHIA Dependence on the input parameters used in PHOTOS: E fraction, Double Bremsstrahlung flag, Interference flag With E fraction= 0.01, Double Bremsstrahlung flag = T, Interference flag=F, Mass Limits for 5  Discovery: => Results in agreement! Lumi PYTHIA PHOTOS 300 fb-1 2300 GeV 2350 GeV 100 fb-1 2000 GeV 2080 GeV Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders Use of PHOTOS Impact of input parameters: CMSJET RMS= 42.44 RMS= 40.01 PHOTOS (0.01, F, F) PHOTOS (0.02, T, T) # Entries RMS= 39.92 RMS= 41.32 PYTHIA PHOTOS (0.01, T, F) Mee (GeV) Exotic Signals at Hadron Colliders 26/02/03

5  Discovery Limit with PHOTOS Theoretical constraint on curvature c G  e+e- Theroretical constraint for no new hierarchy CMSJET MG (GeV) Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders If there is no signal … NS: number of expected signal events NB: number of background events Nobs:number of “observed” events 95% CL Exclusion Limit Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders 95% CL Exclusion Limit CMSJET Excluded Signal Exclusion at 95% CL c |R5| < M52  = 10 TeV Region of interest Photons MG (GeV) Muons Electrons Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders If there is a signal … How to be sure it is a RS Graviton? Graviton? not a Z’? RS model? CMSJET MG=2000 GeV, c=0.01 Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders Angular Distribution Graviton = spin 2 CMSJET pp  G  +- MG=1000 GeV c=0.1 After  cut: ( |  | < 3.0 for e |  | < 2.4 for  ) gg  G  ll: 1-cos4 qqbar  G  ll: 1-3cos2+4cos4 Cos Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders How different from Z’? Kolmogorov-Smirnov Test Rem: No  mode for Z’ CMSJET M= 2000 GeV Z’ 1+ cos2 G For G: number of events corresponding to Lumi, randomly chosen Cos Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders 95% CL Exclusion Limit Spin 1 rejection with 90% probability at 95% CL Excluded CMSJET Electrons Leptons c |R5| < M52  = 10 TeV Region of interest MG (GeV) Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders Detector acceptance || < 2.4 CMSJET || < 1.5 Cos Importance of the pattern recognition in the endcap regions! Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders RS model? Davoudiasl, Hewett, Rizzo hep-ph/0006041 c=1. c=0.5 c=0.1 c=0.05 c=0.01 d/dM Mll (GeV) If the 1st graviton is found, there is a prediction where to find the next resonances for c not too big. Exotic Signals at Hadron Colliders 26/02/03

Exotic Signals at Hadron Colliders Conclusions Signal? Test of Randall Sundrum model after 1 year data taking at the high luminosity design Graviton?  channel or angular distributions of lepton decay products Next Step: Full simulation-reconstruction chain Exotic Signals at Hadron Colliders 26/02/03