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Victoria Athina Giakoumopoulou 3 nd Annual INPP Meeting

Search for High Mass Resonances Decaying in Electron Pairs @8 TeV with the Full 2012 CMS dataset & A Zh studies. Victoria Athina Giakoumopoulou 3 nd Annual INPP Meeting Institute of Nuclear and Particle Physics National Center for Scientific Research “ Demokritos ” June 17, 2013.

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Victoria Athina Giakoumopoulou 3 nd Annual INPP Meeting

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  1. Search for High Mass Resonances Decaying in Electron Pairs @8 TeV with the Full 2012 CMS dataset&AZh studies Victoria AthinaGiakoumopoulou 3nd Annual INPP Meeting Institute of Nuclear and Particle Physics National Center for Scientific Research“Demokritos” June 17, 2013

  2. High Mass Resonance Searches The High Mass Resonances, like Z’, are hypothetical new gauge bosons that arise from some extensions of the SM • Various models of physics beyond the SM predict different kinds of Z’ bosons • Z’SM from sequential SM • Z’χ, Z’ψfrom GUT scenarios (eg E6 grand unification) • Kaluza-Klein excitation of the graviton in the RS model • Search for Large Extra Dimensions in the ADD model (non-resonant) 3nd Annual INP Meeting

  3. ee Data and MC samples We are looking for bumps in the ee or μμ Mass Spectrum • For the SM processes: • DY (Z/γ*) - POWHEG • ttbar, tW – POWHEG, Dibosons (WW, WZ, ZZ) –pythiav6.4 • fromjetsmis-ided as electrons (from data) 3nd Annual INP Meeting

  4. Event Selection • Collected data: • 2012 data at 8TeV, Int. Luminosity = 19.6 fb-1 • Using Certified Good Run List • Trigger: • Double electron trigger with ET > 33 GeV and electron ID criteria • Candidate events with: • 2 electrons, passing electron ID set of cuts • Electron ID cuts • ET > 35 GeV, |η| < 2.5 • H/E cut • shower shape cuts • calorimetric isolation cut • track isolation cut 3nd Annual INP Meeting

  5. Limits (ee – channel)using 19.6 fb-1 of data – s = (8 TeV)2 3nd Annual INP Meeting https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsEXO12061

  6. DC correction effect in the Mass Spectrum using NN We examined the effect of a Dead Cell around the impact point of an electron in the ECAL, especially for the high mass tail events of the M(ee) spectrum, as this might affect the limit calculation. Mass Spectrum of events that contain electrons that have a DC corrected vsuncorrected Full Mass Spectrum corrected vsuncorrected 3nd Annual INP Meeting

  7. Correction on a High Mass event After the correction M(ee)=1065.4 GeV The Mass increases by ~3% 3nd Annual INP Meeting

  8. Limits (ee&μμ– channels)using 19.6 fb-1(ee) and 20.6 fb-1(μμ) of data – s = (8 TeV)2 Most stringent limits to date 3nd Annual INP Meeting

  9. AZh experimental signature • Looking for the CP-odd pseudoscalarHiggs (A) via its decay into a Z boson and the lighter CP-even scalar Higgs (h) which might be the Higgs-like boson recently discovered. • pp A  Zh • Main production mechanism for A is via ggA, ppbbA. • The largest Br(AZh) appears for low tan & Mz+MhMA2Mtop. • The final state under study is Ze+e- , +- (τ+τ-) and hbb. • This study has become interesting in the light of the new higgs-like low mass boson and the possibility of a quite heavy Susy scale 3nd Annual INP Meeting

  10. Basic Event Selection • Collected data: • 2012 data at 8TeV, Int. Luminosity = 19.5 fb-1 • Using Certified Good Run List • Trigger: • Double electron trigger (HLT_Ele17_CaloIdT_CaloIsoVL_TrkIdVL_TrkIsoVL_Ele8_CaloIdT_CaloIsoVL_TrkIdVL_TrkIsoVL_vX) • Single muon trigger (HLT_IsoMu24_eta2p1_vX) • Candidate events with: • 2 OS electrons(muons) with ET(PT) > 30 GeV • passing electron/muon ID set of cuts • 2 bjetswith PT> 3 GeV both tagged • MET < 60 GeV • 70 < Mll < 100 GeV • h, Z PT thresholds, ΔR(Jet,Lepton) cuts and other angular cuts are under study. 3nd Annual INP Meeting

  11. Mllbb @ 8 TeV For these plots NO cut on Mbb 3nd Annual INP Meeting

  12. Summary • With our collaboration with the Z’ CMS group we had a publication of the 7 TeV (5.3 fb-1) and 8 TeV (4.1fb-1) Phys.Lett. B720 (2013) 63-82, http://arxiv.org/abs/arXiv:1212.6175 • The full 8 TeV analysis is public EXO-12-061 • We are working on a long publication with • combination of the 7 TeV and full 8 TeV data • extending on limit calculations on more models • First look at 8 TeV data for the AZh analysis (Thalis obligation) 3nd Annual INP Meeting

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