R-parity from the heterotic string
Mary K. Gaillard · OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) · 2004
In T-duality invariant effective supergravity with gaugino condensation as the mechanism for supersymmetry breaking, there is a residual discrete symmetry that could play the role of R-parity in supersymmetric extensions of the Standard Model.