Studying Hadronic Structure of the Photon in Lattice QCD

Abstract

We show that the matrix element of a local quark-gluon operator in the photon state, $<\gamma (k\lambda )|\hat{O}|\gamma (k\lambda )>$, can be calculated in lattice QCD. The result is generalized to other quantities involving space-like photons, including the transition form factor $\gamma {\gamma }^{\ast }\to {\pi }^0$ and the virtual-photon-nucleon Compton amplitude $<{\gamma }^{\ast }N|{\gamma }^{\ast }N>$ which can be used to define the generalized Drell-Hearn-Gerasimov and Bjorken sum rules.

Comments: 7 pages, 1 figure