Multiplicity dependence of prompt and non-prompt J/ψ production at midrapidity in pp collisions at TeV

Abstract

The yields of prompt and non-prompt J/ψ and the fraction of non-prompt J/ψ are measured at midrapidity (|y| < 0.9) via the dielectron decay channel as a function of the midrapidity charged-particle multiplicity (|η| < 0.9) in pp collisions at TeV. The J/ψ yields and the multiplicity are normalized by their average value in inelastic collisions. The multiplicity-dependent yield ratio between prompt J/ψ and D0 is reported. The multiplicity is further divided into three azimuthal regions with respect to the J/ψ momentum: toward the J/ψ emission direction, transverse, or opposite to it. A stronger-than-linear increase of the self-normalized yields is observed for both prompt and non-prompt J/ψ production, with similar trends. This behaviour is also observed in the toward region, while a weaker increase is observed in the transverse and away regions. © The Author(s) 2026.