Relativistic corrections and high-energy resummation for exclusive heavy quarkonium photoproduction

Abstract

The $O(v^2)$ correction to the high-energy resummed coefficient function for the exclusive photoproduction of vector ($1^{--}$) heavy quarkonia off hadrons is computed, thereby taking into account corrections of $O(v^2{\alpha }_s^n{\ln }^{n-1}(x/\xi ))$. When expressed in terms of the physical vector-meson mass ($M_V$) and the relative heavy-quark velocity ($⟨v^2⟩$) using the Gremm-Kapustin relation, the computed correction turns out to be negligible at the scale ${\mu }_F=M_V$. However, it partially cancels the ${\mu }_F$ dependence of the $O(v^2)$ correction to the LO coefficient function in ${\alpha }_s$, thereby improving the robustness of the predictions.

Comments: 12 pages, 4 figures