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B tagging as a key to New Physics (Physics TDR report)

B tagging as a key to New Physics (Physics TDR report). Valery Andreev UCLA October 9-10, 2006 DOE review, task L. B production. b production at hadron colliders Huge cross section Challenge for perturbative QCD New physics searches: b jets as a signal feature. Analysis.

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B tagging as a key to New Physics (Physics TDR report)

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  1. B tagging as a key to New Physics(Physics TDR report) Valery Andreev UCLA October 9-10, 2006 DOE review, task L

  2. B production • b productionat hadron colliders • Huge cross section • Challenge for perturbative QCD • New physics searches: b jets as a signal feature DOE review, Oct. 9-10, 2006

  3. Analysis • B production total cross section • Differential cross sections d/dpt’ d/d • Selection (b-tag) • Particular interest – semileptonic b-decays into muons • Background (b purity) • Trigger efficiency • Luminosity DOE review, Oct. 9-10, 2006

  4. Analysis status • Talk at APS April 2006 meeting, Dallas D.B. Cline • Inclusive B production measurement at LHC with CMS • CMS note 2006/120; June 12, 2006 • Measurement of open beauty production at LHC with CMS • CMS PTDR chapter 7.3; July 2006 • Physics of b-quarks and hadrons • Poster presentation at ICHEP06, Moscow, July 2006 • V.P.Andreev, D.B.Cline, S. Otwinowski, X.W. Meng, J.Q. Tao, G.M. Chen, C. Eggel, U. Langenegger, A. Starodumov Prospects for B physics measurements using the CMS detector at the LHC • Talk at DPF2006, Honolulu; October 2006 V. Andreev • Measurement of open beauty production at LHC with CMS DOE review, Oct. 9-10, 2006

  5. CMS Physics TDR DOE review, Oct. 9-10, 2006

  6. Prospects for B Physics Measurements using the CMS Detector at the LHC Valery P. Andreev, D. B. Cline, S. Otwinowski - UCLA, Los Angeles, USA X. W. Meng, J. Q. Tao, G. M. Chen - ICHEP, Beijing, China C. Eggel, U. Langenegger, A. Starodumov - ETH Zurich, PSI Villigen, Switzerland XXXIII International Conference on High Energy Physics, Moscow, 2006 Abstract The LHC provides new opportunities to improve our understanding of the b quark using the high statistics data samples and the 14 TeV center-of-mass energy. The prospects to measure the cross section for inclusive b production in events containing jets and at least one muon are presented. Additionally, the feasibility for CMS to measure the mass and the lifetime of the Bc meson and to search for the rare leptonic decay Bs are presented.  Detailed studies of detector systematic effects and theoretical uncertainties are included. Inclusive b-quark production b resolution b purity Uncertainties • QCD event Generation: PYTHIA • Full simulation of the detector b Trigger Level-1: single m, pt>14 GeV/c, || < 2.1 e = 18 % (b and c semi-leptonic decays) High Level Trigger: “muon + b-jet”, Pt >19GeV/c,Etjet>50GeV, || < 2.4 e = 60 % c udsg • The most energetic b tagged jet as • the reconstructed B-particle candidate • The resolutions for B-particles with • pT > 170 GeV/c are 13 % and 6% for • pT and pseudorapidity (), respectively. The statistical uncertainty for the cross section measurement (triangles), systematic (squares) uncertainty and total (dots) uncertainty as function of the b tagged jet transverse momentum • from the fit of the distribution of the muon pT with respect to the closest b tagged jet • the event fractions are well reproduced within statistical errors • Off-line selection • B-tagged jet: Et > 50 GeV, || < 2.4 • e = 65 % (barrel), 55 % (endcap) • Muon associated with B-tagged jet • e = 75 % Conclusion • The event selection for inclusive b production measurement at CMS will allow event sample of 16 million b events for 10 fb-1 luminosity • The b purity varies as function of the transverse momentum in a range from 70 % to 55 % • With the CMS detector we can reach 1.5 TeV/c as the highest measured transverse momentum of B hadrons Study of Bchadrons Estimated number of signal and background events for 1 fb-1 • the goal is to measure the mass and the lifetime of • Bc meson with the CMS detector • the mass of Bc can be predicted using potential models, the range of predictions corresponds to 6.24  0.05 GeV/c2 Mass and lifetime fitting Event selection • a kinematic fit with J/ mass constrait • Bc mass resolution of 0.022 GeV/c2 • proper decay length resolution of 25 m • systematic uncertainties on the mass and on • c are estimated to be 0.015 GeV/c2 and 3.0 m • feasibility study concentrated on the J/  channel • two muon tracks with pt>4 GeV/c, || < 2.2 having • opposite charge, within J/ mass window 3.0  3.2 GeV/c2 • additional track at the same vertex of the J/ inconsistent with being a muon or an electron Conclusion About 120 signal events would be observed by CMS for 1 fb-1 of data to measure the Bc mass with 22.0 MeV/c2 (stat)  14.9 (syst)MeV/c2 uncertainty, and 0.044 (stat)  0.010 (syst) ps lifetime uncertainty Discovery potential for Bs   • Trigger • Level-1: • di-muon, pt >3 GeV/c, || < 2.1 • High Level Trigger: • di-muon, pt >4 GeV/c, || < 2.4 • opposite charge • sec. Vertex fit with 2 < 20 • 3D flight length > 150 m • MB  150 MeV/c2 • Reconstructed Bs candidates after • L1 trigger • transverse momentum • pseudorapidity • mass resolution • decays highly suppressed in the Standard Model • could be highly enhanced by New Physics Conclusion Event selection • with 10 fb-1 luminosity the selection allows for 6.1 signal events and 13.8 background events • corresponding 90 % C.L. upper limit on the branching fraction Signal and background events • QCD event Generation: PYTHIA • Full simulation of the detector Signal sample DOE review, Oct. 9-10, 2006 [1] V. P. Andreev, D. B. Cline, S.Otwinowski CERN-CMS-NOTE-2006-120 Measurement of open beauty production at LHC with CMS [2] X. W. Meng, J. Q. Tao, G. M. Chen CERN-CMS-NOTE-2006-118 Feasibility to study the Bc meson at CMS [3] C. Eggel, U. Langenegger, A. Starodumov CMS NOTE in preparation Discovery potential for Bs + References

  7. Results from two-photon collisions at LEP Valery P. Andreev UCLA Representing the DELPHI, L3 and OPAL Collaborations ICHEP2006 International Conference on High Energy Physics July 27-August 2, 2006 Moscow, Russia

  8. Event selection QCD event Generation: PYTHIA Full simulation of the detector Trigger Level-1: “single m”, pt>14 GeV/c, || < 2.1 e = 18 % (b and c semi-leptonic decays) High Level Trigger: “muon + b-jet”, Pt >19GeV/c, Etjet>50GeV, || < 2.4 e = 60 % DOE review, Oct. 9-10, 2006

  9. Event selection 2.5 M simulated events processed Estimate for 10 fb-1 DOE review, Oct. 9-10, 2006

  10. Level 1 trigger efficiency DOE review, Oct. 9-10, 2006

  11. High Level (HLT) trigger efficiency DOE review, Oct. 9-10, 2006

  12. Off-line selection • B-tagged jet: Et > 50 GeV, || < 2.4 • e = 65 % (barrel), 55 % (endcap) Muon associated with B-tagged jet e = 75 % • The most energetic b tagged jet as • the reconstructed B-particle candidate DOE review, Oct. 9-10, 2006

  13. B tagging efficiency DOE review, Oct. 9-10, 2006

  14. B jet resolution Pt > 170 GeV/c  = 12.9 %  = 5.7 % DOE review, Oct. 9-10, 2006

  15. B tagging with muon The tagged muon is inside of the b jet DOE review, Oct. 9-10, 2006

  16. B tagging with muon efficiency ( b and c semi-leptonic decays) DOE review, Oct. 9-10, 2006

  17. Fit results QCD events MC: 230 < Pt < 300 GeV/c Muon Pt w.r.t. the closest B jet Nb =5250 (56 % Nc = 2388 (26% Nudsg= 1740(18% --------- 9378 events b c udsg Fit: Nb =5222  501 Nc = 2050  728 Nudsg =1778 341 --------- 9050 events DOE review, Oct. 9-10, 2006

  18. Systematics (10 fb-1) • luminosity 5 % • tagging 5 % • event selection 6 % • trigger 3 % • jet energy scale 12% • misalignment 2 % • fragmentation 9 % • tt background 0.7 % • muon • Br. Ratio 2.6 % • Eff. total = 18 % DOE review, Oct. 9-10, 2006

  19. b-quark Pt reach We can reach 1.5 TeV as the highest measured B hadron Pt DOE review, Oct. 9-10, 2006

  20. Plans • Collaboration with Florida Tech group of Prof. Marc Baarmand has already started • joined MC request for bb-events ( 3.5 Million events) submitted • Switch to the new CMS software CMSSW • refresh inclusive b-quark production analysis • Searches with b-tagging and muons • Z -> bb • Bs -> -+ • Try inclusive b measurement at 900 GeV LHC start-up _ DOE review, Oct. 9-10, 2006

  21. Z bb: jets, muons, b-jets DOE review, Oct. 9-10, 2006

  22. decay Our study: Mass resolution 47 MeV DOE review, Oct. 9-10, 2006

  23. Conclusion • The event selection for inclusive b production measurement at CMS will allow event sample of 16 million b events for 10 fb-1 luminosity • The b purity varies as function of the transverse momentum in a range from 70 % to 55 % • With the CMS detector we can reach 1.5 TeV/c as the highest measured transverse momentum of B hadrons Outlook • Apply b-tagging tested on the huge inclusive b sample to the • New Physics search • Looking forward to beam next year ! DOE review, Oct. 9-10, 2006

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