Low-energy photon and pion scattering in holographic QCD

TL;DR

This paper uses holographic QCD models to derive new relations between QCD matrix elements and analyzes processes like pion scattering and photon interactions, showing good agreement with experimental data.

Contribution

It introduces a novel set of relations between QCD matrix elements derived from holographic models with chiral symmetry breaking.

Findings

The amplitudes depend on a single scalar function h(Q^2).

Phenomenological analysis agrees with experimental cross sections.

Polarizabilities at low energies match previous computations and experiments.

Abstract

Using holographic models where chiral symmetry is broken through IR b.c.'s, we determine a novel set of relations between QCD matrix elements. In particular, we find that the amplitudes of the three processes pi pi->pi pi, gamma gamma->pi pi and gamma->pi pi pi involve a single scalar function h(Q^2) given by a suitable 5D integral of the EoM Green's function. In a phenomenological analysis of gamma gamma->pi pi we find an overall agreement with the experimental cross section for a broad range of energy. Moreover, the polarizabilities at low energies show a fair agreement between the holographic approach, previous computations and experiment.