J/psi and psi(2S) production in pp collisions at sqrt(s) = 7 TeV

TL;DR

This paper reports measurements of J/psi and psi(2S) production cross sections in proton-proton collisions at 7 TeV using CMS data, distinguishing prompt and non-prompt sources, and providing insights into charmonium production mechanisms.

Contribution

First measurement of prompt and non-prompt J/psi and psi(2S) production cross sections at 7 TeV with detailed kinematic dependence and polarization-independent results.

Findings

Cross sections measured as functions of transverse momentum and rapidity.

The ratio of production cross sections of J/psi to psi(2S) is determined.

Branching fraction of B to psi(2S) X decay is extracted.

Abstract

A measurement of the J/psi and psi(2S) production cross sections in pp collisions at sqrt(s)=7 TeV with the CMS experiment at the LHC is presented. The data sample corresponds to an integrated luminosity of 37 inverse picobarns. Using a fit to the invariant mass and decay length distributions, production cross sections have been measured separately for prompt and non-prompt charmonium states, as a function of the meson transverse momentum in several rapidity ranges. In addition, cross sections restricted to the acceptance of the CMS detector are given, which are not affected by the polarization of the charmonium states. The ratio of the differential production cross sections of the two states, where systematic uncertainties largely cancel, is also determined. The branching fraction of the inclusive B to psi(2S) X decay is extracted from the ratio of the non-prompt cross sections to be: BR(B to psi(2S) X) = (3.08 +/- 0.12(stat.+syst.) +/- 0.13(theor.) +/- 0.42(BR[PDG])) 10^-3