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

We analyze the proton decay via dimension six operators in supersymmetric image-grand unified models based on intersecting D6-brane constructions in type IIA string theory orientifolds. We include in addition to image interactions also the operators arising from image 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 image 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 image, which could be up to a factor of three shorter than that predicted in field theory.