UV Sensitivity in Supersymmetric Large Extra Dimensions: The Ricci-flat Case

TL;DR

This paper analyzes the UV-sensitive one-loop Casimir energy in Ricci-flat compactifications of higher-dimensional supergravity, exploring implications for the cosmological constant problem within supersymmetric large extra dimensions.

Contribution

It identifies the UV dependence and divergences of Casimir energy contributions in Ricci-flat compactifications, constrained by higher-dimensional covariance, with implications for SLED models.

Findings

UV dependence constrained by higher-dimensional covariance

Computed effects of co-dimension 2 branes with small tension

Supports SLED as a potential solution to the cosmological constant problem

Abstract

We examine the ultraviolet (UV)-sensitive part of the one-loop Casimir energy which is induced when various higher-dimensional supergravities are compactified to 4D on extra dimensions which are Ricci flat, but otherwise arbitrary. We identify the leading dependence on the mass of very massive higher-dimensional modes, as well as the UV divergent part of the contributions of modes which are massless in the higher-dimensional sense (but which consist of a KK tower of massive modes from the 4D perspective), and show how these are constrained by higher-dimensional general covariance. Some of the implications of co-dimension 2 branes are computed in the limit where their tension is small compared with the extra-dimensional Planck scale (but not small compared with the observed dark energy). Our results support the interpretation of supersymmetric large extra dimensions (SLED) in 6 dimensions as a potential solution to the cosmological constant problem (but do not yet completely clinch the case).