Energy evolution of J/$\psi$ production in DIS on nuclei

Abstract

In this paper we show, that the $J/\psi$ production in DIS, is the main source of information about the events with two parton shower production. We attempt to develop our theoretical acumen of this process, to a level compatible with the theoretical description of inclusive DIS. We revisit the problem of the linear evolution equation for the double gluon densities, and include Bose-Einstein enhancement to these equations. We find that the Bose-Einstein correlations lead to an increase of the anomalous dimension, which turns out to be suppressed as $1/(N_c^2-1{)}^2$, in agreement with the estimates for the twist four anomalous dimension. We believe that understanding what happens to these contributions at ultra high energies, is a key question for an effective theory, based on high energy QCD. We derive the evolution equation for the scattering amplitude of two dipoles with a nucleus, taking into account the shadowing corrections, and investigate the analytical solutions in two distinct kinematic regions: deep in the saturation region, and in the vicinity of the saturation scale. The suggested non-linear evolution equation is a direct generalization of the Balitsky-Kovchegov equation, which has to be solved with the initial condition that depends on the saturation scale $Q_s(Y=Y_0,b)$. With the goal of finding a new small parameter, it is instructive to compare the solution of the non-linear equation with the qusi-classical approximation, in which in the initial condition we replace $Q_s(Y=Y_0,b)$ by $Q_s(Y,b)$. Our final result is that the shadowing corrections in the elastic amplitude generate the survival probability, which suppresses the growth of the amplitude with energy, caused by the Bose-Einstein enhancement.

21pp. 8 figures in eps files

References in corpus (11)

• Universality of Unintegrated Gluon Distributions at small x
• Angular Correlations in Gluon Production at High Energy
• Exclusive vector meson production at HERA from QCD with saturation
• One gluon, two gluon: multigluon production via high energy evolution
• Summing Pomeron loops in the dipole approach
• Collectivity from interference
• Gluon saturation effects on J/Psi production in heavy ion collisions
• Inclusive gluon production in the dipole approach: AGK cutting rules
• Perturbative QCD and beyond: azimuthal angle correlations in deuteron-deuteron scattering from Bose-Einstein correlations
• Recombination within multi-chain contributions in pp scattering
• Bose-Einstein correlations in perturbative QCD: $v_n$ dependence on multiplicity

Cited by in corpus (3)

• $J/\psi$ production in hadron scattering: three-pomeron contribution
• Multiplicity distributions as probes of quarkonia production mechanisms
• Energy evolution and the Bose-Einstein enhancement for double parton densities