Chatrchyan, S.Işıldak, Bora2014-11-232014-11-232013-041748-0221http://hdl.handle.net/10679/649https://doi.org/10.1088/1748-0221/8/04/P04013At the Large Hadron Collider, the identification of jets originating from b quarks is important for searches for new physics and for measurements of standard model processes. A variety of algorithms has been developed by CMS to select b-quark jets based on variables such as the impact parameters of charged-particle tracks, the properties of reconstructed decay vertices, and the presence or absence of a lepton, or combinations thereof. The performance of these algorithms has been measured using data from proton-proton collisions at the LHC and compared with expectations based on simulation. The data used in this study were recorded in 2011 at root s = 7TeV for a total integrated luminosity of 5.0 fb(-1). The efficiency for tagging b-quark jets has been measured in events from multijet and t-quark pair production. CMS has achieved a b-jet tagging efficiency of 85% for a light-parton misidentification probability of 10% in multijet events. For analyses requiring higher purity, a misidentification probability of only 1.5% has been achieved, for a 70% b-jet tagging efficiency.enginfo:eu-repo/semantics/restrictedAccessArticle800031746240002010.1088/1748-0221/8/04/P04013Performance of high energy physics detectorsLarge detector-systems performancePattern recognition, cluster finding, calibration and fitting methods2-s2.0-84877788842