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Old Data selection

Towards the first f KK preliminary observation in CMS P. Bortignon, T. Dorigo, M. Galanti, L. Perrozzi, F. Ptochos, F. Simonetto. Old Data selection. G. Petrucciani private skims 5.7K “good” events /castor/cern.ch/user/g/gpetrucc/900GeV/DATA/

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Old Data selection

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  1. Towards the first fKKpreliminary observationin CMSP. Bortignon, T. Dorigo, M. Galanti, L. Perrozzi, F. Ptochos, F. Simonetto

  2. Old Data selection • G. Petrucciani private skims • 5.7K “good” events • /castor/cern.ch/user/g/gpetrucc/900GeV/DATA/ • bit40-123596-stdReco-fitBS123592v2-lumi1-68.root • bit40-123596-stdReco-fitBS123592v2-lumi69-129.root • bit40-123596-stdReco-fitBS123592v2-lumi130-143.root We used all available lumisections (1-143) due to low statistics Luca Perrozzi - CMSSWPD meeting

  3. Track candidate selection • Track quality basic requirements: • Reduced chi2 < 2 • ndof > 5 • |eta| < 2.0 • pt > 0.5 GeV • dxy < 0.3 cm wrt beamspot (0.205,0.158,-2.69) • number of tracks per event < 150 • opposite charge Luca Perrozzi - CMSSWPD meeting

  4. gaus const gaus mean Preliminary Phi candidates • Fits are made with B+S custom function: [0]*pow(100*(x-[1]),[2])+[3]*exp(-pow(x-[4],2)/pow([5],2)) • Sigma is fixed from MC estimate (3.5 MeV) ALL tracks Luca Perrozzi - CMSSWPD meeting

  5. dE/dx improvement • dE/dx distribution can be fitted for various particles (p,p,K) cfr http://www.fynu.ucl.ac.be/users/l.quertenmont/MesDocuments/MesPresentations/09_12_07_SiStrip_dEdX.pdf • K hypothesis: for a given momentum p<1 GeV dE/dx must lie in region around the fit 2.48 + [(MK)2 * 2.53]/(p*p) obtained relaxing the K (dE/dx measured) mass: 0.5407±0.2 GeV (for p>1 GeV we do not apply dE/dx cuts) Luca Perrozzi - CMSSWPD meeting p (GeV)

  6. gaus const gaus mean dE/dx improved (still preliminary) Phi candidates dE/dx K hypothesis Result shown at CMS week Physics plenary dE/dx background Luca Perrozzi - CMSSWPD meeting

  7. New plot request on Sunday evening! • New VERY GOOD runs taken during 11 dec • Dataset (open): /MinimumBias/BeamCommissioning09-PromptReco-v2/RECO • Runs: 123997, 124009, 124020, 124022, 124023, 124024, 124027, 124030 • They are stored also in Legnaro (Grazie Ezio!) • Good events increased by a factor 100 • NO beam halo request (tech bit) included • Thanks to Skype conference feature it was possible to coordinate ourselves even if spread over Europe  Luca Perrozzi - CMSSWPD meeting

  8. new Phi candidates This is the signal Peak size enormously increased! Do not worry, this is the BACKGROUND  Luca Perrozzi - CMSSWPD meeting

  9. Summary • Last 10 days were extremely exhausting but very exciting • First observation of Phi  KK resonance in CMS has been achieved by Padova/Cyprus group • LHC (and CMS itself) seem to be in a good shape: stay tuned! Luca Perrozzi - CMSSWPD meeting

  10. J/Psi event in 2.36 TeV run *** Discussion title: B-Physics Dear all, We believe to have found a nice J/Psi candidate in the 2.36 TeV run from this morning. The run number is 124120, the event is 5686693 The two muons have the following specs: Mu1: Charge  1, pT 3.6 GeV, Eta 2.03, Phi 3.11, 4 matches Mu2: Charge -1, pT 2.6 GeV, Eta 1.81, Phi 2.09, 3 matches The invariant mass comes out to be 3.07 GeV. I guess the hunt for the peak can begin :-) For some event displays, see http://wwweth.cern.ch/susy/JPsi/ Best, Benjamin, Frederic, Kostas, Viola Luca Perrozzi - CMSSWPD meeting

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