Diffractive production of S and D wave vector mesons in DIS

In this work the production of vector mesons in diffractive DIS is analyzed, with an emphasis on the impact of the internal spin structure of a vector meson upon its virtual photoproduction rate. We derived the full sets of s-channel helicity conserving and violating amplitudes for pure S and D wave vector mesons and found a striking difference between S and D wave vector meson production. First, in the case of helicity conserving amplitudes, D wave vector mesons were found to exhibit dramatically different Q^2-behavior due to abnormally large higher twist contributions. Besides, we found that helicity conserving amplitudes for S and D states are numerically comparable, which makes the physical rho meson very sensitive to D wave admixture. Second, the helicity violating amplitudes turned out large both for S and D wave states of light vector mesons and for D wave heavy vector mesons as well. Aiming at producing sort of a manual on the diffractive vector meson production, we carried out all calculations in a pedagogical manner with maximally full presentation of intermediate steps and accompanied them with detailed qualitative discussion.