Abstract
The identification of jets originating from b quarks is an important component in analyses searching for new physics and for measurements of standard model processes. Particularly challenging are those involving top-quark or Higgs-boson production with decays in the boosted regime. %DBAM Studies of b-quark jet algorithms and their performances are presented, using multijet events and $\rm{t}\bar{\rm t}$ events recorded in proton-proton collision data at $\sqrt{s}=8$~TeV with the CMS detector in the year 2012. The b-tagging efficiency and misidentification probability are determined in data and in simulation over a wide range of jet transverse momenta from 20~GeV$/c$ to more than 800~GeV$/c$. For the first time in CMS, dedicated studies of b-quark identification in boosted topologies are presented. %DBAM