We investigate the role that baryon number violating interactions may play in
B phenomenology. Present in various grand unified theories, supersymmetric
theories with R-parity violation and composite models, a diquark state could be
quite light. Using the data on B decays as well as B−Bˉ mixing, we
find strong constraints on the couplings that such a light diquark state may
have with the Standard Model quarks.Comment: 19 pages, latex, no figures, 13 tables include