Discrete Gauge Symmetries, Baryon Number and Large Extra Dimensions

TL;DR

This paper explores how unbroken discrete gauge symmetries can protect protons from decay in theories with large extra dimensions, considering constraints on such symmetries from gravitational effects.

Contribution

It identifies the restrictions on discrete gauge symmetries compatible with the standard model or MSSM in the context of large extra dimensions.

Findings

Discrete gauge symmetries can protect protons from gravitational decay.

Restrictions on the space of possible discrete symmetries are derived.

Implications for low-scale quantum gravity scenarios are discussed.

Abstract

Krauss and Wilczek have shown that an unbroken discrete gauge symmetry is respected by gravitationally mediated processes. This has led to a search for such a symmetry compatible with the standard model or MSSM that would protect protons from gravitationally mediated decay in a universe with a low scale for quantum gravity (large extra dimensions). The fact that the discrete symmetry must remain unbroken and have a gauge origin puts important restrictions on the space of possible discrete symmetries.