Large momentum transfer electroproduction of mesons

Abstract

Assuming the proton's light-cone wave function to be dominated by small parton virtualities and small intrinsic transverse momenta, we show that the electroproduction amplitudes at large momentum transfer factorize into parton-level subprocess amplitudes and form factors representing 1/x-moments of skewed parton distributions. On the basis of a wave function overlap model for the form factors we present detailed predictions for the electroproduction cross sections. We also comment on large momentum transfer photoproduction.

Figures (10)

• Figure 1: The handbag-type diagram for electroproduction of mesons. The large blob represents a sum over all spectator configuration. $k$ and $k'$ denote the momenta of the active partons. The small blob stands for meson electroproduction off partons.
• Figure 2: Light-cone plus and transverse components of hadron, photon and parton momenta in the symmetric frame.
• Figure 3: Lowest order Feynman graphs contributing to the subprocess $\gamma^*q\rightarrow Mq$ where $q$ is either a quark or an antiquark. The upper quark and antiquark lines enter the meson's wave function. The internal curly lines represent hard gluons.
• Figure 4: Parton picture of the soft proton matrix element.
• Figure 5: Lowest order Feynman graphs for the subprocess $\gamma^* g\to Mg$.