Measurement of the ratio of inclusive cross sections σ(pp̄→ Z+b-quark jet)/σ(pp̄→Z+jet) at √s=1.96TeV

The ratio of the cross section for pp interactions producing a Z boson and at least one b-quark jet to the inclusive Z+jet cross section is measured using 4.2 fb -1 of pp collisions collected with the D0 detector at the Fermilab Tevatron collider at √s=1.96 TeV. The Z→l + l - candidate events with at least one b jet are discriminated from Z+charm and light jet(s) events by a novel technique that exploits the properties of the tracks associated to the jet. The measured ratio is 0.0193±0.0027 for events having a jet with transverse momentum p τ >20 GeV and pseudorapidity |η|≤2.5, which is the most precise to date and is consistent with theoretical predictions.