The cross sections for inelastic photoproduction of J/ψ and ψ′ mesons have been measured in ep collisions with the ZEUS detector at HERA, using an integrated luminosity of 468 pb−1 collected in the period 1996–2007. The ψ′ to J/ψ cross section ratio was measured in the range 0.55 < z < 0.9 and 60 < W < 190GeV as a function of W , z and pT . Here W denotes the photon-proton centre-of-mass energy, z is the fraction of the incident photon energy carried by the meson and pT is the transverse momentum of the meson with respect to the beam axis. The J/ψ cross sections were measured for 0.1 < z < 0.9, 60 < W < 240 GeV and pT > 1 GeV. Theoretical predictions within the non- relativistic QCD framework including NLO colour-singlet and colour-octet contributions were compared to the data, as were predictions based on the kT -factorisation approach.
Measurement of inelastic J/ψ and ψ′ photoproduction at HERA
DE PASQUALE, Salvatore;
2013-01-01
Abstract
The cross sections for inelastic photoproduction of J/ψ and ψ′ mesons have been measured in ep collisions with the ZEUS detector at HERA, using an integrated luminosity of 468 pb−1 collected in the period 1996–2007. The ψ′ to J/ψ cross section ratio was measured in the range 0.55 < z < 0.9 and 60 < W < 190GeV as a function of W , z and pT . Here W denotes the photon-proton centre-of-mass energy, z is the fraction of the incident photon energy carried by the meson and pT is the transverse momentum of the meson with respect to the beam axis. The J/ψ cross sections were measured for 0.1 < z < 0.9, 60 < W < 240 GeV and pT > 1 GeV. Theoretical predictions within the non- relativistic QCD framework including NLO colour-singlet and colour-octet contributions were compared to the data, as were predictions based on the kT -factorisation approach.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
