Soft photon anomaly and gauge/string duality

TL;DR

This paper uses gauge/string duality to calculate soft photon production in strongly coupled N=4 super Yang-Mills theory, revealing a new non-perturbative source of soft photons with spherical angular distribution.

Contribution

It provides the first exact calculation of inclusive soft photon cross section at strong coupling, connecting gauge theory results with experimental anomalies.

Findings

Energy distribution matches Bremsstrahlung pattern

Angular distribution is spherical

Identifies a new non-perturbative photon source

Abstract

Motivated by the recent DELPHI report on the anomalous photon production in e^+e^- annihilation, we exactly calculate the inclusive cross section of soft photons in the strong coupling limit of N=4 super Yang-Mills. We find that the energy distribution is that of the Bremsstrahlung, while the angular distribution is spherical. Our result elucidates a new non-perturbative source of soft photons not associated with the final state hadronic Bremsstrahlung.