Misc,
Identification of b-quark jets with the CMS experiment
(2012)arxiv:1211.4462.
Abstract
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%. For analyses requiring higher purity, a misidentification
probability of only 1.5% has been achieved, for a 70% b-jet tagging efficiency.
