  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.

High Energy Physics - Theory;High Energy Physics - Phenomenology