A photon mass on the brane

TL;DR

This paper explores how introducing a bulk photon mass in a brane-world model affects the photon mass on the brane and the transition to higher-dimensional electromagnetic laws, with implications for experimental detection.

Contribution

It demonstrates that a bulk photon mass modifies the brane photon propagator, resulting in a small photon mass and delaying observable five-dimensional effects to super-horizon scales.

Findings

Photon acquires a small mass consistent with current bounds.

Transition to five-dimensional electromagnetic laws occurs only at super-horizon scales.

Fermion propagators are also analyzed with brane and bulk Dirac terms.

Abstract

We discuss the impact of a bulk photon mass in a Dvali-Gabadadze-Porrati type brane model with Maxwell terms both on the brane and in the bulk, as proposed by Dvali, Gabadadze and Shifman. The motivation to include the bulk photon mass is to suppress radiation loss into the bulk. We point out that this modifies the photon propagator in such a way that it generates a small photon mass on the brane. Compatibility with present bounds on a photon mass imply that the transition to five-dimensional distance laws for the electromagnetic potentials would appear only at super-horizon length scales, thus excluding any direct detection possibility of a transition from four-dimensional to five-dimensional distance laws in electromagnetic interactions. We also include results on fermion propagators with Dirac terms on the brane and in the bulk.