Resummation of threshold logarithms in deeply-virtual Compton scattering

Abstract

I derive an all-order resummation formula for the logarithmically enhanced contributions proportional to $\frac{{\alpha }_s^n}{x\pm \xi }\log (\frac{\xi \pm x}{2\xi }{)}^k$ in the quark coefficient function of deeply-virtual-Compton scattering and the pion-photon transition form factor in momentum space. The resummation is performed at the next-to-next-to-leading logarithmic accuracy. The key observation is that the quark coefficient function itself factorizes in the $x\to \pm \xi$ limit, which allows for a resummation using renormalization group equations. A preliminary numerical analysis suggests that the corrections due to resummation for the quark contribution might be small.

Comments: Published version