At 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 sqrt(s) = 7 TeV for a total integrated
luminosity of 5.0 inverse femtobarns. 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.

本文讨论了 CMS 在大型强子对撞机上使用多种算法通过诸如荷电粒子轨迹的冲击参数、重构衰变顶点的属性和存在或不存在只有电子，或两者结合的变量来选择起源于 b 夸克的喷注。