Invariant mass (left) and pT (right) of the lepton pairs after the dilepton+b-jet selection. The yellow bands in the lower plots represent the statistical uncertainty on the Monte Carlo yield.
The production of b jets in association with a Z/γ* boson is studied using proton-proton collisions delivered by the LHC at a centre-of-mass energy of 7 TeV and recorded by the CMS detector. The inclusive production rates for Z/γ* + b-jet is measured in a sample corresponding to an integrated luminosity of 2.2 fb−1 (inverse femtobarns). The Z/γ* + b-jet production rate with Z/γ* to ll (where ll = ee or μμ) for events with the invariant mass 60 T > 25 GeV and |η| 0.5 is found to be 5.84 ± 0.08 (stat.) ± 0.72 (syst.) −0.44+0.25 (theory) pb. The kinematic properties of the events are also studied and found to be in agreement with predictions.