CMS CollaborationCiftciR.2019-10-272019-10-2720131748-02211748-0221https://doi.org/10.1088/1748-0221/8/04/P04013https://hdl.handle.net/11454/24741At 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 s = 7 TeV 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. © 2013 IOP Publishing Ltd and Sissa Medialab srl.en10.1088/1748-0221/8/04/P04013info:eu-repo/semantics/closedAccessLarge detector-systems performancePattern recognition, cluster finding, calibration and fitting methodsPerformance of High Energy Physics DetectorsArticle84Q2