Searches for Resonances in dilepton final states Searches for Resonances in dilepton final states PANIC th -14 th November 2008, Eilat, ISRAEL A. Canepa for the CDF Collaboration

November 10 th 2008 A. Canepa 2 Outline Tevatron Collider In this talk ! The current energy frontier !  Proton-antiproton collider   s = 1.96 TeV at  t = 396 ns Peak luminosity, 321  cm -2 s -1  Lepton flavor conserving models  New U’(1), Extra-dimensions  Lepton flavor violating models  SUSY  Maximal Flavor Violation models

November 10 th 2008 A. Canepa 3 CDF at Tevatron Silicon Tracker Central Outer Tracker Central EM Calorimeter Central HAD Calorimeter Muon chambers Central Shower Max (CES) Data for the searches collected with single muon (electron) trigger at p T (E T ) > 18 GeV

November 10 th 2008 A. Canepa 4 Used for normalization to data Di-mass resolution constant in m  -1 Di-mass resolution constant in m  -1 Z’  (I) New U’(1) spontaneously broken  new massive Z’ boson coupling to SM fields Optimized calibration of COT p T correction using E/p p T scale from Z Events with two muons p T > 30 GeV  Main backgrounds from  EWK processes  Cosmic rays  Kaons and jet misID as leptons Data statistically consistent with the SM expectations (p-value 6.6%) 2.3 fb -1

November 10 th 2008 A. Canepa 5 Z’  (II) Likelihood fitter  95% C.L. upper limit on the number of signal events  35 bins in search region m  -1 < 10 TeV -1  Resonant pole width  = 2.8%  M  Assume no interference between SM Z/  * and Z’ SM like Z’ m > 1.03 TeV/c 2 at 95% C.L

November 10 th 2008 A. Canepa 6 Z’  ee Energy scale from Z 2.5  significant excess in [228; 250] GeV SM like Z’ m > 966 TeV/c 2 at 95% C.L 2.5 fb -1 Events with two electrons E T > 25 GeV  Main backgrounds from  EWK processes  jet misID as leptons

November 10 th 2008 A. Canepa 7 G  RS model of warped extra-dimensions  gravitons propagating in the bulk KK tower of excited modes couple to SM fields k/M Pl = 0.1 m > 850 GeV/c 2 at 95% C.L Scale of the model  ~ M Pl e -k  R k = curvature of space-time Coupling ~ 1/ 

November 10 th 2008 A. Canepa 8 sneutrino  SUperSYmmetry  New boson (fermion) partner for each SM fermion (boson) Lepton (or baryon) number violation allowed in the theory “Single” coupling dominance 2  BR = 0.01 m > 810 GeV/c 2 at 95% C.L  

November 10 th 2008 A. Canepa 9 sneutrino  e , , e  (I) New algorithm for ID of energetic hadronic taus New algorithm for ID of energetic hadronic taus  To probe lepton flavor violation decay, select events with taus decaying hadronically! Calibration of CES detector to improve resolution of tau visible momentum Response of hadronic calorimeter tuned to data

November 10 th 2008 A. Canepa 10 sneutrino  e , , e  (II) Events with one muon (electron) p T (E T ) > 20 GeV and one hadronic tau Visible E T > 25 GeV  Major backgrounds  EWK and W+jet  jets and  misID as leptons 1.0 fb -1 Background in signal region extrapolated from low mass region ee  ee

November 10 th 2008 A. Canepa 11 sneutrino  e , , e  (III) Mass cut derived from best expected limit  Data statistically consistent with the SM expectations in all search channels  BR excluded at 95% C.L in the :10 -1 pb range ee  ee

November 10 th 2008 A. Canepa 12 N jets  0  LS leptons (I) SM + Max Flavor Violation  SM + scalar doublet SIGNAL 2 like-sign leptons, 2 neutrinos, 1 b-jet and 0,1 or 2 light jets SIGNAL 2 like-sign leptons, 2 neutrinos, 1 b-jet and 0,1 or 2 light jets 2.0 fb -1 Events with 2 LS muons (electrons) p T (E T ) > 20 GeV, MET > 20 GeV, 1 b-tagged jet Expect high cross sections Weak experimental limits !

November 10 th 2008 A. Canepa 13  0  LS leptons (II) Binned likelihood fit of jet multiplicity to extract the signal  Assume  + heavy  not accessible at TeV   real and  31 =  13   0  ut dominant decay Exclude natural values of ξ=1 at low masses

November 10 th 2008 A. Canepa 14 Summary For updates, No signal of New Physics seen  World best limits set on Z’, RS gravitons, sneutrino  More data to be analyzed in the next years! CDF explored up to 2.5 fb -1 of Tevatron collision data searching for high mass resonances decaying into leptons