String Constraints on Discrete Symmetries in MSSM Type II Quivers

TL;DR

This paper investigates the occurrence of discrete gauge symmetries in D-brane models of the MSSM, finding that Proton hexality is rare and family-dependent symmetries are absent in these configurations.

Contribution

It systematically searches for discrete gauge symmetries in local D-brane realizations of the MSSM, highlighting their rarity and the absence of family-dependent symmetries.

Findings

Proton hexality is rarely realized in these models.

No family-dependent discrete gauge symmetries are found.

Discrete symmetries that prevent R-parity violation are uncommon.

Abstract

We study the presence of discrete gauge symmetries in D-brane semi-realistic compactifications. After establishing the constraints on the transformation behaviour of the chiral matter for the presence of a discrete gauge symmetry we perform a systematic search for discrete gauge symmetries within local semi-realistic D-brane realizations, based on four D-brane stacks, of the MSSM and the MSSM with three right-handed neutrinos. The systematic search reveals that Proton hexality, a discrete symmetry which ensures the absence of R-parity violating terms as well as the absence of dangerous dimension 5 proton decay operators, is only rarely realized. Moreover, none of the semi-realistic local D-brane configurations exhibit any family dependent discrete gauge symmetry.