• Energy Research

The relative rates of B-meson decays into J/ψ and ψ(2S) mesons are measured for the three decay modes in pp collisions recorded with the LHCb detector. The ratios of branching fractions ([Formula: see text]) are measured to be [Formula: see text] where the third uncertainty is from the ratio of the ψ(2S) and J/ψ branching fractions to μ+μ-.

AbstractUsing 34.7 pb−1 of data collected with the LHCb detector, the inclusive production of the X(3872) meson in pp collisions at $\sqrt{s}=7\mbox{~TeV}$ is observed for the first time. Candidates are selected in the X(3872)→J/ψπ+π− decay mode, and used to measure "Equation missing" 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 $$m_{X(3872)} = 3871.95 \pm0.48 \ (\mathrm{stat}) \pm0.12 \ (\mathrm {syst})\ \mathrm{MeV}/c^2 $$ and $$m_{\psi(2S)} = 3686.12\pm0.06 \ (\mathrm{stat}) \pm0.10 \ (\mathrm {syst})\ \mathrm{MeV}/c^2. $$