Measurement of forward $J/\ddot{I}ˆ$ production cross-sections in $pp$ collisions at $\sqrt{s}=13$ TeV

Abstract

The production of $J/\ddot{I}ˆ$ mesons in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=13$ TeV is studied with the \lhcb detector. Cross-section measurements are performed as a function of the transverse momentum $p_{\mathrm{T}}$ and the rapidity $y$ of the $J/\ddot{I}ˆ$ meson in the region $p_{\mathrm{T}}<14\mathrm{GeV}/c$ and $2.0<y<4.5$, for both prompt $J/\ddot{I}ˆ$ mesons and $J/\ddot{I}ˆ$ mesons from $b$-hadron decays. The production cross-sections integrated over the kinematic coverage are $15.03\pm 0.03\pm 0.94$ $\hat{I}¼$b for prompt $J/\ddot{I}ˆ$ and $2.25\pm 0.01\pm 0.14$ $\hat{I}¼$b for $J/\ddot{I}ˆ$ from $b$-hadron decays, assuming zero polarization of the $J/\ddot{I}ˆ$ meson. The first uncertainties are statistical and the second systematic. The cross-section reported for $J/\ddot{I}ˆ$ mesons from $b$-hadron decays is used to extrapolate to a total $b\bar{b}$ cross-section. The ratios of the cross-sections with respect to $\sqrt{s}=8$ TeV are also determined.

All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-037.html. An erratum has been submitted, and the contents of the errata are reflected in this manuscript