Recombination mechanism for D0-meson production and D0−D0‾ production asymmetry in the LHCb p+20Ne fixed-target experiment

Abstract

We discuss production of neutral D mesons in proton-proton collisions at the LHC (fixed target mode) in the framework of the BJM recombination model. We present rapidity and transverse momentum distributions of D mesons and compare the recombination contribution to the dominant gluon-gluon fusion mechanism. Both the direct production, as dictated by the matrix element, and fragmentation of the associated c or c¯ are included. The latter mechanism generates D mesons with smaller rapidities than those produced directly. We calculate the D0+D‾0 meson distributions relevant for fixed target p+4He collisions at s = 86.6 GeV as well as for p+20Ne collisions at s = 69 GeV. The recombination component is consistent with the LHCb data and in addition results in production asymmetry. The asymmetries in D0−D0‾ production as a function of rapidity and transverse momentum are shown and the cancellation of terms for direct production and associated c/c¯ fragmentation is discussed.

Keywords

• Charm quarks
• Open charm meson
• Recombination