Measurement of the associated production of a Z boson and b quarks in pp collision at 8 TeV

The study of the production of a Z boson in association with at least one jet originating from a b quark in proton-proton collisions at $\sqrt{s} = 8$~TeV is presented. Differential cross sections are measured on data collected by CMS in 2012, for a total integrated luminosity of 19.8~fb$^{-1}$, using Z boson decays into electrons or muons, and identified b quark jets. Cross sections are measured as a function of observables characterizing the b jet and Z boson kinematics, and ratios of differential cross sections for the associated production with at least a b jet and with any jet are presented. In the case where two b quark jets are reconstructed, differential cross sections are also measured for observables describing the kinematics of the dijet system. Results are compared to theoretical predictions, testing two different flavour schemes for the choice of initial state partons.