Measurement of the X(3872) production cross section via decays to J/ψπ + π − in pp collisions at $ \sqrt{s}=7 $ TeV

Abstract

AbstractThe production of the X(3872) is studied in pp collisions at$ \sqrt{s}=7 $TeV, using decays to J/ψπ+π−, where the J/ψdecays to two muons. The data were recorded by the CMS experiment and correspond to an integrated luminosity of 4.8 fb−1. The measurements are performed in a kinematic range in which the X(3872) candidates have a transverse momentum 10 < pT < 50 GeV and rapidity |y| < 1.2. The ratio of the X(3872) andψ(2S) cross sections times their branching fractions into J/ψπ+π−is measured as a function ofpT. 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 ofpTis extracted. Theπ+π−mass spectrum of the J/ψπ+π−system in the X(3872) decays is also investigated.