Diffractive production of vector mesons in Deep Inelastic Scattering within kt-factorization approach

In this work we give a theoretical description of the elastic vector meson production in diffractive DIS developed within the kt-factorization formalism. Since the kt-factorization scheme does not require large values of Q+mV , we conduct an analysis that is applicable to all values of Q from photoup to highly virtual production of vector mesons. The basic quantity in this approach — the unintegrated gluon structure function — was for the first time extracted from the experimental data on F2p, thoroughly investigated, and consistently used in the vector meson production calculation. Moreover, by limiting ourselves to the lowest Fock state of the vector meson, we were able to construct in a closed form the theory of spin-angular coupling in the vector meson. This allowed us for the first time to address the production of a vector meson in a given spin-angular state. We performed an extensive analytical and numerical investigation of the properties of 1S, 2S, and D-wave vector meson production reactions. Treating the physical ground state vector mesons as purely 1S states, we observed a good overall agreement with all available experimental data on vector meson production. For the excited states, our analysis predicts a picture which is remarkably different from 1S-state, so that such reactions can be regarded as potential sources of new information on the structure of excited states in vector mesons.