Forward rapidity J/ψ production as a function of charged-particle multiplicity in pp collisions at √s = 5.02 and 13 TeV

The production of J/psi is measured as a function of charged-particle multiplicity at forward rapidity in proton-proton (pp) collisions at center-of-mass energies root s = 5.02 and 13 TeV. The J/psi mesons are reconstructed via their decay into dimuons in the rapidity interval (2.5 < y < 4.0), whereas the charged-particle multiplicity density (dN(ch)/d eta) is measured at midrapidity (vertical bar eta vertical bar < 1). The production rate as a function of multiplicity is reported as the ratio of the yield in a given multiplicity interval to the multiplicity-integrated one. This observable shows a linear increase with charged-particle multiplicity normalized to the corresponding average value for inelastic events (dN(ch)/d eta/< dN(ch)/d eta >), at both the colliding energies. Measurements are compared with available ALICE results at midrapidity and theoretical model calculations. First measurement of the mean transverse momentum (< p(T)>) of J/psi in pp collisions exhibits an increasing trend as a function of dN(ch)/d eta/< dN(ch)/d eta > showing a saturation towards high charged-particle multiplicities.