Constraints onR-parity violating supersymmetry from leptonic and semileptonicτ,Bd,andBsdecays

We put constraints on several products of R-parity violating $\lambda {\lambda }^{\prime }$ and ${\lambda }^{\prime }{\lambda }^{\prime }$ type couplings from leptonic and semileptonic $\tau ,$ $B_d,$ and $B_s$ decays. Most of them are one to two orders of magnitude better than the existing bounds, and almost free from theoretical uncertainties. A significant improvement of these bounds can be made in high luminosity tau charm or B factories.