Proton decay via dimension-six operators in intersecting D6-brane models

TL;DR

This paper investigates proton decay in intersecting D6-brane models within Type IIA string theory, providing detailed string vertex operators and calculating decay rates that slightly enhance previous field theory estimates.

Contribution

It offers explicit construction of string vertex operators for relevant fields and computes proton decay rates, bridging string theory and field theory predictions in GUT models.

Findings

Proton lifetime estimated at (0.5-2.1) x 10^{36} years.

String contributions can shorten proton lifetime predictions by up to a factor of three.

Explicit vertex operators for chiral superfields in intersecting D-brane setups.

Abstract

We analyze the proton decay via dimension six operators in supersymmetric SU(5)-Grand Unified models based on intersecting D6-brane constructions in Type IIA string theory orientifolds. We include in addition to 10* 10 10* 10 interactions also the operators arising from 5-bar* 5-bar 10* 10 interactions. We provide a detailed construction of vertex operators for any massless string excitation arising for arbitrary intersecting D-brane configurations in Type IIA toroidal orientifolds. In particular, we provide explicit string vertex operators for the 10 and 5-bar chiral superfields and calculate explicitly the string theory correlation functions for above operators. In the analysis we chose the most symmetric configurations in order to maximize proton decay rates for the above dimension six operators and we obtain a small enhancement relative to the field theory result. After relating the string proton decay rate to field theory computations the string contribution to the proton lifetime is tau^{ST}_p =(0.5-2.1) x 10^{36} years, which could be up to a factor of three shorter than that predicted in field theory.