Measurement of the X(3872) production cross section via decays to J/psi pi pi in pp collisions at sqrt(s) = 7 TeV

TL;DR

This paper reports the measurement of the X(3872) production cross section in proton-proton collisions at 7 TeV, using its decay to J/psi pi pi, providing insights into its production mechanisms and decay properties.

Contribution

First measurement of the X(3872) production cross section and decay characteristics in pp collisions at 7 TeV by the CMS experiment.

Findings

Measured the ratio of X(3872) to psi(2S) cross sections as a function of pt.

Determined the fraction of X(3872) from B decays.

Extracted the prompt X(3872) differential cross section.

Abstract

The production of the X(3872) is studied in pp collisions at sqrt(s) = 7 TeV, using decays to J/psi pi pi, where the J/psi decays to two muons. The data were recorded by the CMS experiment and correspond to an integrated luminosity of 4.8 inverse femtobarns. The measurements are performed in a kinematic range in which the X(3872) candidates have a transverse momentum 10 < pt < 50 GeV and rapidity abs(y) < 1.2. The ratio of the X(3872) and psi(2S) cross sections times their branching fractions into J/psi pi pi is measured as a function of pt. In addition, the fraction of X(3872) originating from B decays is determined. From these measurements the prompt X(3872) differential cross section times branching fraction as a function of pt is extracted. The pi pi mass spectrum of the J/psi pi pi system in the X(3872) decays is also investigated.