The perturbative limit of the two-pion distribution amplitude

TL;DR

This paper derives an expression for the two-pion light-cone distribution amplitude in the perturbative limit of large photon virtuality and energy, confirming known scaling and symmetry properties in this regime.

Contribution

It provides a new derivation of the two-pion distribution amplitude in the perturbative limit, connecting it to conventional pion distribution amplitudes.

Findings

Reproduces known scaling behavior

Confirms helicity selection rule

Establishes symmetry relations

Abstract

We consider pion pair production in two-photon collisions, gamma* gamma -> pi+ pi-, at large photon virtuality Q^2 and center-of-mass energy \sqrt{s} in the hard-scattering picture. In the limit where s is large but s << Q^2 we derive an expression for the two-pion light-cone distribution in terms of the conventional pion distribution amplitudes. Our result reproduces the well-known scaling behavior, helicity selection rule and symmetry relations in this regime.