Measurement of J/psi production in pp collisions at sqrt(s)=7 TeV

TL;DR

This paper reports measurements of J/psi meson production cross-sections in proton-proton collisions at 7 TeV using the LHCb detector, providing detailed differential cross-sections and decay fractions in specific kinematic ranges.

Contribution

It provides the first detailed measurements of prompt and non-prompt J/psi production cross-sections at 7 TeV in the specified kinematic region, with systematic and acceptance uncertainties.

Findings

Prompt J/psi cross-section: 10.52 mub

J/psi from b-hadron decays: 1.14 mub

Results are consistent with theoretical models

Abstract

The production of J/psi mesons in proton-proton collisions at sqrt(s)=7 TeV is studied with the LHCb detector at the LHC. The differential cross-section for prompt J/psi production is measured as a function of the J/psi transverse momentum pT and rapidity y in the fiducial region 0<pT<14 GeV/c and 2.0<y<4.5. The differential cross-section and fraction of J/psi from b-hadron decays are also measured in the same pT and y ranges. The analysis is based on a data sample corresponding to an integrated luminosity of 5.2pb-1. The measured cross-sections integrated over the fiducial region are 10.52 +/- 0.04 +/- 1.40 +1.64/-2.20 mub for prompt J/psi production and 1.14 +/- 0.01 +/- 0.16 mub for J/psi from b-hadron decays, where the first uncertainty is statistical and the second systematic. The prompt J/psi production cross-section is obtained assuming no J/psi polarisation and the third error indicates the acceptance uncertainty due to this assumption.