R-parity violating enhancement of Bu+→ℓ+ν and Bc+→ℓ+ν

We study the decays B+u→ℓ+ν and B+c→ℓ+ν in the context of the Minimal Supersymmetric Standard Model (MSSM) with explicit R-parity violation. We analyse the correlation between the two decays and show that branching ratios (BRs) for B+c→ℓ+ν may be of order 5% (over 40% in one case), without violating current bounds on B+u→ℓ+ν. Although Bc mesons are inaccessible at the e+e− B factories, such large BRs for B+c→ℓ+ν would possibly be within experimental observability at LEP and the Tevatron Run II, with much larger yields expected at the hadronic B factories. We also update some earlier bounds on products of R-parity violating couplings in the light of new experimental results.