Electroproduction of J/ψ Mesons within the Semihard QCD Approach and the Color-Singlet Model.

The deep-inelastic production of J/ψ mesons in electron–proton interactions at the HERA collider is considered within the semihard (k[sub T]-factorization) QCD approach and within the color-singlet model. The dependence of the Q[sup 2], p[sub T][sup 2], z, y[sup *], and W distributions of J/ψ mesons on various sets of unintegrated gluon distributions and the dependence of the spin parameter α on p[sub T][sup 2] and Q[sup 2] are investigated. The results of the calculations are compared with the latest experimental data obtained by the H1 and ZEUS Collaborations at the HERA collider. It is shown that experimental investigations of the polarization properties of J/ψ mesons over the kinematical region Q[sup 2] < 1 GeV[sup 2] may provide an additional test of the statement that the dynamics of gluon distributions is governed by the Balitsky–Fadin–Kuraev–Lipatov equations.© 2003 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]