GUTs with Exclusively Delta-B=1, Delta-L=0 R-Parity Violation

We study $R$-parity violation in the framework of GUTs, focusing on the case that $R$-parity is broken exclusively through $\Delta B=1$, $\Delta L=0$ effective interactions. We construct two such models, an $SU(5)$ and an $SU(5)\times U(1)_{X}$ model, in which $R$-parity breaking is induced through interactions with extra supermassive fields. The presence of only the Baryon Number violating operators ${d^c}{d^c}{u^c}$ requires an asymmetry between quarks and leptons, which is achieved either by virtue of the Higgs representations used or by modifications in the matter multiplets. The latter possibility is realized in the second of the above models, where the left-handed leptons have been removed from the representation in which they normaly cohabit with the right-handed up quarks and enter as a combination of the isodoublets in $(\bf {{\overline{5}},-3})$ and $(\bf {5,-2})$ representations. In both models the particle content below the GUT scale is unaffected by the introduced $R$-parity breaking sector.