Constraints on the R-parity Violating Couplings from $B^\pm \to l^\pm \nu$ Decays

We derive the upper bounds on certain products of R-parity- and lepton-flavor-violating couplings from $B^\pm \to l^\pm \nu$ decays. These modes of B-meson decays can constrain the product combinations of the couplings with one or more heavy generation indices which are comparable with or stronger than the present bounds. And we investigate the possible effects of R-parity violating interactions on $B_c \to l \nu$ decays. These decay modes can be largely affected by R-parity violation.