Inclusive $b+Z$, $Z\rightarrow \mu^+\mu^-, e^+e^-$ production at CMS

The production of Z bosons in association with at least one b-jet and Z decaying into muons or electrons is studied. This analysis is done by using proton-proton collisions delivered by the Large Hadron Collider (LHC) at a centre of mass energy of 7 TeV and with data recorded by the CMS detector (CMS) in 2010, representing an integrated luminosity of 36 pb$^{-1}$. We require a final state of two well identified muons or electrons and at least one b-tagged jet in order to perform this study. The event yields and shapes of kinematic variables are compared with Monte Carlo predictions from MADGRAPH. The ratio $ \sigma(Z+b) /\sigma( Z+j)$ is found to be 0.054$\pm$0.016 (0.046$\pm$0.014) in the data for the Z$\rightarrow$ee (Z$\rightarrow\mu\mu$) selection, compared to 0.043$\pm$0.005 (0.047$\pm$0.005) estimated from NLO theory predictions.