Study of $Z$ bosons produced in association with charm in the forward region

Abstract

Events containing a $Z$ boson and a charm jet are studied for the first time in the forward region of proton-proton collisions. The data sample used corresponds to an integrated luminosity of $6{\mathrm{fb}}^{-1}$ collected at a center-of-mass energy of 13 TeV with the LHCb detector. In events with a $Z$ boson and a jet, the fraction of charm jets is determined in intervals of $Z$-boson rapidity in the range $2.0<y(Z)<4.5$. A sizable enhancement is observed in the forward-most $y(Z)$ interval, which could be indicative of a valence-like intrinsic-charm component in the proton wave function.

All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2021-029.html (LHCb public pages)