Diphoton generalized distribution amplitudes

Abstract

We calculate the leading order diphoton generalized distribution amplitudes by calculating the amplitude of the process ${\ensuremath{\gamma}}^{*}\ensuremath{\gamma}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}$ in the low energy and high photon virtuality region at the Born order and in the leading logarithmic approximation. As in the case of the anomalous photon structure functions, the $\ensuremath{\gamma}\ensuremath{\gamma}$ generalized distribution amplitudes exhibit a characteristic $\mathrm{ln}{Q}^{2}$ behavior and obey inhomogeneous QCD evolution equations.