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

Valery Andreev, UCLADOE review, Oct. 9-10, B production b production at hadron colliders –Huge cross section –Challenge for perturbative QCD –New physics searches: b jets as a signal feature

Valery Andreev, UCLADOE review, Oct. 9-10, Analysis B production total cross section Differential cross sections d  /dp t’ d  /d  –Selection (b-tag) Particular interest – semileptonic b-decays into muons –Background (b purity) –Trigger efficiency –Luminosity

Valery Andreev, UCLADOE review, Oct. 9-10, 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

Valery Andreev, UCLADOE review, Oct. 9-10, CMS Physics TDR

Valery Andreev, UCLADOE review, Oct. 9-10, 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 B c meson and to search for the rare leptonic decay B s  are presented. Detailed studies of detector systematic effects and theoretical uncertainties are included. Off-line selection B-tagged jet: E t > 50 GeV, |  | < 2.4  = 65 % (barrel), 55 % (endcap)  Muon associated with B-tagged jet  = 75 % QCD event Generation: PYTHIA Full simulation of the detector Inclusive b-quark production Trigger Level-1: single , p t >14 GeV/c, |  | < 2.1  = 18 % (b and c semi-leptonic decays) High Level Trigger: “muon + b-jet”, P t  >19GeV/c,E t jet >50GeV, |  | < 2.4  = 60 % 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 References [1] V. P. Andreev, D. B. Cline, S.Otwinowski CERN-CMS-NOTE Measurement of open beauty production at LHC with CMS [2] X. W. Meng, J. Q. Tao, G. M. Chen CERN-CMS-NOTE Feasibility to study the B c meson at CMS [3] C. Eggel, U. Langenegger, A. Starodumov CMS NOTE in preparation Discovery potential for B s   +   b resolution The most energetic b tagged jet as the reconstructed B-particle candidate The resolutions for B-particles with p T > 170 GeV/c are 13 % and 6% for p T and pseudorapidity (  ), respectively. b purity from the fit of the distribution of the muon p T with respect to the closest b tagged jet the event fractions are well reproduced within statistical errors b c udsg Uncertainties 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 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 B c hadrons the goal is to measure the mass and the lifetime of B c meson with the CMS detector the mass of B c can be predicted using potential models, the range of predictions corresponds to 6.24  0.05 GeV/c 2 Event selection feasibility study concentrated on the J/   channel two muon tracks with p t >4 GeV/c, |  | < 2.2 having opposite charge, within J/  mass window 3.0  3.2 GeV/c 2 additional track at the same vertex of the J/  inconsistent with being a muon or an electron Estimated number of signal and background events for 1 fb -1 Mass and lifetime fitting a kinematic fit with J/  mass constrait B c mass resolution of GeV/c 2 proper decay length resolution of 25  m systematic uncertainties on the mass and on c  are estimated to be GeV/c 2 and 3.0  m Conclusion About 120 signal events would be observed by CMS for 1 fb -1 of data to measure the B c mass with 22.0 MeV/c 2 (stat)  14.9 (syst)MeV/c 2 uncertainty, and (stat)  (syst) ps lifetime uncertainty Discovery potential for B s   decays highly suppressed in the Standard Model could be highly enhanced by New Physics QCD event Generation: PYTHIA Full simulation of the detector Signal and background events Trigger Level-1: di-muon, p t >3 GeV/c, |  | < 2.1 High Level Trigger: di-muon, p t >4 GeV/c, |  | < 2.4 opposite charge sec. Vertex fit with  2 < 20 3D flight length > 150  m M B  150 MeV/c 2 Signal sample Event selection Reconstructed B s candidates after L1 trigger a)transverse momentum b)pseudorapidity c)mass resolution Conclusion 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

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

Valery Andreev, UCLADOE review, Oct. 9-10, Event selection QCD event Generation: PYTHIA Full simulation of the detector Trigger Level-1: “single  ”, p t >14 GeV/c, |  | < 2.1  = 18 % (b and c semi-leptonic decays) High Level Trigger: “muon + b-jet”, P t  >19GeV/c, E t jet >50GeV, |  | < 2.4  = 60 %

Valery Andreev, UCLADOE review, Oct. 9-10, Event selection 2.5 M simulated events processed Estimate for 10 fb -1

Valery Andreev, UCLADOE review, Oct. 9-10, Level 1 trigger efficiency

Valery Andreev, UCLADOE review, Oct. 9-10, High Level (HLT) trigger efficiency

Valery Andreev, UCLADOE review, Oct. 9-10, Off-line selection B-tagged jet: E t > 50 GeV, |  | < 2.4  = 65 % (barrel), 55 % (endcap) Muon associated with B-tagged jet  = 75 % The most energetic b tagged jet as the reconstructed B-particle candidate

Valery Andreev, UCLADOE review, Oct. 9-10, B tagging efficiency

Valery Andreev, UCLADOE review, Oct. 9-10, B jet resolution  = 12.9 %  = 5.7 % P t > 170 GeV/c

Valery Andreev, UCLADOE review, Oct. 9-10, B tagging with muon The tagged muon is inside of the b jet

Valery Andreev, UCLADOE review, Oct. 9-10, B tagging with muon efficiency  b and c semi-leptonic decays)

Valery Andreev, UCLADOE review, Oct. 9-10, Fit results Muon P t w.r.t. the closest B jet QCD eventsMC: 230 < P t < 300 GeV/c Nb =5250 (56 % Nc = 2388 (26% Nudsg= 1740(18% events Fit: Nb =5222  501 Nc = 2050  728 Nudsg =1778  events b c udsg

Valery Andreev, UCLADOE review, Oct. 9-10, 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 %

Valery Andreev, UCLADOE review, Oct. 9-10, b-quark P t reach We can reach 1.5 TeV as the highest measured B hadron P t

Valery Andreev, UCLADOE review, Oct. 9-10, 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 B s ->  -  + Try inclusive b measurement at 900 GeV LHC start-up _

Valery Andreev, UCLADOE review, Oct. 9-10, Z  bb: jets, muons, b-jets

Valery Andreev, UCLADOE review, Oct. 9-10, decay Our study: Mass resolution 47 MeV

Valery Andreev, UCLADOE review, Oct. 9-10, 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 !