B Tagging studies with non prompt J/Ψ's Alberto Escalante del Valle Juan Pablo Fernández Ramos CIEMAT 2/5/2013 BTV performance meeting

Introduction: Content: Evaluate the b-tagging efficiencies and scale factors using a specific subsample of b-jets (those with Bhadrons→ J/ψ+X ) in 2012 data and Summer12 MC vs Jet-pt (standard for reference). Using tag and probe technique Content: Selection Method Comparison of relevant variables B-tag efficiency definition Results Systematics Conclusions

Selection for b-tagging ● Muon cuts : #hits > 10 ; χ2 < 10 ; # μ-cham > 0 ● Emulate Inclusive J/psi triggers in MC : • DCA cut between the two muons of < 0.5 cm. • Lxy-significance > 3 • ptμ1 + ptμ2 > 10 GeV • cosα > 0.9 ● |dz(PV)μ1|< 0.2 && |dz(PV)μ2|< 0.2 (PU cut) ● | DiMu invmass - m(J/ψ) | < 0.1 GeV, sidebands: [2.7,2.9] ∪ [3.3,3.5] ● Tag with Reco::PFJets with : • ΔR (J/ψ, jet) < 0.5 • ptjet> 10 GeV && |ηjet |< 2.5 • Number of charged (charged+neutral) tracks in jet >= 1 (2) • Pileup subtraction with FastJet & L2, L3 corrections ● Look for any other away-jet with: • ΔR (J/ψ, jet) > 0.5 • Previous requirements in pt, n tracks, pileup subtraction & L2,L3 corrections

Sample for b-tagging 18.7 fb-1 Run2012A,B,C,D : /MuOnia/Run2012A-22Jan2013-v1/AOD /MuOnia/Run2012B-22Jan2013-v1/AOD /MuOnia/Run2012C-22Jan2013-v1/AOD /MuOnia/Run2012D-22Jan2013-v1/AOD 18.7 fb-1 Summer12 MC : MC weights : /BpToPsiMuMu_2MuPtEtaFilter_8TeV-pythia6-evtgen/ Summer12_DR53X-PU_S10_START53_V7A-v1/AODSIM /B0ToPsiMuMu_2MuPtEtaFilter_8TeV-pythia6-evtgen/ /BsToPsiMuMu_2MuPtEtaFilter_8TeV-pythia6-evtgen/ /LambdaBToPsiMuMu_2MuPtEtaFilter_8TeV-pythia6-evtgen/ Summer12_DR53X-PU_S10_START53_V7A-v2/AODSIM /JPsiToMuMu_2MuPtEtaFilter_tuneD6T_8TeV-pythia6-evtgen/ Weight B+=(2.11E-4 * 6.087222E7)/58574844.; B0=(1.97E-4 * 5.4402708E7)/50562450.; Bs=(7.2E-5 * 4.940354E7)/14859324.; LambdaB=(3.6E-5 *1.6467847E7)/2338904.; prompt=(0.04923 *1.377539E7)/10533602.;

Comparison of relevant variables MC & data Pile up distribution : MC was generated with the same Pile up

Comparison of relevant variables (II) ● | DiMu invmass - m(J/ψ) | < 0.1 GeV, sidebands: [2.7,2.9] ∪ [3.3,3.5] DiMuinvMass TCHP

Coparison of relevant variables (III) CSV Reasonable agreement on btag-discriminators. Jet probability

Comparison of relevant variables (IV) CSVr Reasonable agreement on rCSV btag-discriminator and somewhat different CSV+SL (not affecting the analysis , see OP's) CSV+SL Operational points for CSVSL CSVSLL - 0.527 CSVSLM- 0.756 CSVSLT - 0.859

Method for b-tagging => Using tag and probe technique ● Tag : J/ψ – jet ● Probe : any other jet in the event Divide the sample in bins of pt of the jet For each pt-bin plot the lifetime discriminant variable for data and perform a fit. The fit uses light, c and b templates from MC Fit output: B-fraction (fb) The fit is done for a sample before (tag) fbbefore tag and after (all) fbtag b-tagging Apply independent tagger sample before tag => Using tag and probe technique ● Tag : J/ψ – jet ● Probe : any other jet in the event Divide the sample in bins of pt of the jet For each pt-bin plot the lifetime discriminant variable for data and perform a fit. The fit uses light, c and b templates from MC Fit output: B-fraction (fb) The fit is done for a sample before (tag) fbbefore tag and after (all) fbtag b-tagging sample with (tag) b-tagging

Results: B-tag efficiencies The b-tag efficiency is taken from equation 4 of BTV-12-001 • Definition (for a given pt-bin) Cb = Fraction of events with tag info. All plots are sideband subtracted Will show results for JPM, CVSM and CSV+SL M b-tagging algorithms

B-tagging efficiencies and SF (I) JPM Tagged jet Probe jet

B-tagging efficiencies and SF (II) CSVM Tagged jet Probe jet

B-Tagging efficiencies and SF (III) CSV+SL M Tagged jet Probe jet

Systematics ● Analysis of the btagging efficiency as a function of the variation of the following selection cuts. New values chosen for the evaluation of the systematic uncertainty: ●ΔR (J/ψ, jet) > 0.5 [0.4] ●|ΔR(J/ψ, probejet) - π|< 0.2 [0.15,0.25] ●Lxy-significance > 3 [2,4] ●ptμ1 + ptμ2 > 10 GeV [8,12] ● cos α > 0.9 [0.85,0.95] ●|dz(PV)μ1|< 0.2 && |dz(PV)μ2|< 0.2 [0.15,0.25] ●| DiMu invmass - m(J/ψ) | < 0.1 [0.075,0.125] ● In addition we study the pileup dependence .

Systematics ( |ΔR(J/ψ, probejet) - π|<0.2 ) ΔR jet B fraction decreases (bef & after tagging) when increasing the deltaR probe window, for ptjet< 65 GeV. Despite this dependence, the SF do not change. J/ψ jet probe jet B Fraction fbtag fbbefore tag

Systematics ( ptμ1 + ptμ2 > 10 GeV) Despite the ptμ1 + ptμ2 Data /MC disagreement, btagging efficiency and SF do not present changes when including the low ptμ1 + ptμ2 region. fbtag fbbefore tag

Systematics ( Lxy-significance > 3 ) JPM JPM Tagged jet Probe jet CSVM CSVM Tagged jet Probe jet

Pileup dependence (not taken as systematics) B fraction JPM JPM Probe jet B fraction But SF's do not change B fraction changes at low pt CSVM Probe jet CSVM

SF (JPM)

SF (CSVM)

SF (CSV+SL) M

Summary SF (18.7 fb-1 2012data/Summer12MC) using 22 Jan 2013 data obtained for the probe jet ( the SF are within 10 %) SF's for the probe jet shown to be independent of any of the selection cuts, despite the variation of B fraction at low pt. Included an analysis using different criteria for probe jet. Links to the full study of systematics uncertainties and default plots in the backup. To do: Write the note of the analysis Wait for approval, before providing SF's.

Backup Default cuts : http://wwwae.ciemat.es/~escalante/jpsi/plots_default/plots.php Systematic studies : Cosalpha : http://wwwae.ciemat.es/~escalante/jpsi/plots_cosalpha/plots.php Z0 : http://wwwae.ciemat.es/~escalante/jpsi/plots_z0/plots.php ΔR : http://wwwae.ciemat.es/~escalante/jpsi/plots_deltaR/plots.php Lxys : http://wwwae.ciemat.es/~escalante/jpsi/plots_lxys/plots.php Ptsum : http://wwwae.ciemat.es/~escalante/jpsi/plots_ptsum/plots.php ΔR probe : http://wwwae.ciemat.es/~escalante/jpsi/plots_deltaRprobe/plots.php Pileup : http://wwwae.ciemat.es/~escalante/jpsi/plots_pileup/plots.php Mass : http://wwwae.ciemat.es/~escalante/jpsi/plots_mass/plots.php η : http://wwwae.ciemat.es/~escalante/jpsi/plots_rap/plots.php