LHCb first J/ψ cross-section measurement

The first LHCb measurement of the J/ψ production cross-section is presented. The differential production cross-section is measured as a function of the J/ψ transverse momentum pT in the range and rapidity y in the range y∈[2.5;4]. The analysis is based on a sample of 14.2 nb−1 collected between April and June 2010 at the pp Large Hadron Collider at CERN, at a center-of-mass energy . The fraction of J/ψ coming from b-hadron decays is estimated using the J/ψ pseudo-propertime.