Study of $J/\ddot{I}ˆ$ production in jets

Abstract

The production of $J/\ddot{I}ˆ$ mesons in jets is studied in the forward region of proton-proton collisions using data collected with the LHCb detector at a center-of-mass energy of 13 TeV. The fraction of the jet transverse momentum carried by the $J/\ddot{I}ˆ$ meson, $z\equiv p_{\mathrm{T}}(J/\ddot{I}ˆ)/p_{\mathrm{T}}(\mathrm{jet})$, is measured using jets with $p_{\mathrm{T}}(\mathrm{jet})>20$ GeV in the pseudorapidity range $2.5<\hat{I}\cdot (\mathrm{jet})<4.0$. The observed $z$ distribution for $J/\ddot{I}ˆ$ mesons produced in $b$-hadron decays is consistent with expectations. However, the results for prompt $J/\ddot{I}ˆ$ production do not agree with predictions based on fixed-order non-relativistic QCD. This is the first measurement of the $p_{\mathrm{T}}$ fraction carried by prompt $J/\ddot{I}ˆ$ mesons in jets at any experiment.

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-2016-064.html; v2 updated to journal version