Constrained Perturbative Expansion of the DGP Model

TL;DR

This paper investigates the vDVZ discontinuity in the 5D DGP model by applying a constrained perturbative expansion, demonstrating that the discontinuity is absent in most of the parameter space.

Contribution

It introduces a constrained perturbative expansion method for the DGP model, showing the vDVZ discontinuity occurs only in a measure-zero subset of parameters.

Findings

vDVZ discontinuity is absent in most parameter space

Constrained perturbative expansion clarifies the model's behavior

Supports the viability of the DGP model without discontinuity

Abstract

We address the vDVZ discontinuity of the 5D DGP model which consists of a 3-brane residing in a flat, infinite-volume bulk. Following a suggestion by Gabadadze [hep-th/0403161], we implement a constrained perturbative expansion parametrized by brane gauge parameters. We explore the parameter space and show that the DGP solution exhibiting the vDVZ discontinuity corresponds to a set of measure zero.