Observation of X(3872) production in pp collisions at s√=7~TeV

Abstract

Using 34.7 pb−1 of data collected with the LHCb detector, the inclusive production of the X(3872) meson in pp collisions at s√=7~TeV

is observed for the first time. Candidates are selected in the X(3872)→J/ψπ + π − decay mode, and used to measure

where σ(pp→X(3872)+anything) is the inclusive production cross section of X(3872) mesons with rapidity in the range 2.5–4.5 and transverse momentum in the range 5–20 GeV/c. In addition the masses of both the X(3872) and ψ(2S) mesons, reconstructed in the J/ψπ + π − final state, are measured to be mX(3872)=3871.95±0.48 (stat)±0.12 (syst) MeV/c2

and mψ(2S)=3686.12±0.06 (stat)±0.10 (syst) MeV/c2.