Measurements of ψ(2S) and X(3872)→J/ψπ+π− production in pp collisions at s√=8 TeV with the ATLAS detector

F. MONTICELLI; ATLAS

JOURNAL OF HIGH ENERGY PHYSICS

SPRINGER

Lugar: Berlin; Año: 2016

1126-6708

Differential cross sections are presented for the prompt and non-prompt production of the hidden-charm states X(3872) and ψ(2S), in the decay mode J/ψπ+π−, measured using 11.4 fb−1 of pp collisions at s√=8 TeV by the ATLAS detector at the LHC. The ratio of cross-sections X(3872)/ψ(2S) is also given, separately for prompt and non-prompt components, as well as the non-prompt fractions of X(3872) and ψ(2S). Assuming independent single effective lifetimes for non-prompt X(3872) and ψ(2S) production gives RB=B(B→X(3872) + any)B(X(3872→J/ψπ+π−)B(B→ψ(2S) + any)B(ψ(2S)→J/ψπ+π−)=(3.95±0.32(stat)±0.08(sys))×10−2, while separating short- and long-lived contributions, assuming that the short-lived component is due to Bc decays, gives RB=(3.57±0.33(stat)±0.11(sys))×10−2, with the fraction of non-prompt X(3872) produced via Bc decays for pT(X(3872))>10 GeV being (25±13(stat)±2(sys)±5(spin))%. The distributions of the dipion invariant mass in the X(3872) and ψ(2S) decays are also measured and compared to theoretical predictions.