Search for B̄0 → Λ + cΛ ̄̄ cdecay at Belle
We search for the doubly charmed baryonic decay B̄0 → Λ + cΛ ̄̄ cin a data sample of 520 × 106 B ̄B events accumulated at the γ(4S) resonance with the Belle detector at the KEKB asymmetricenergy e+e- collider. We find no significant signal and set an upper limit of B B̄0 → Λ + cΛ ̄̄ c) 6.2 × 10-5 at 90% confidence level. The result is significantly below a naive extrapolation fromB(B̄→ Ε0 c̄ Λc ) assuming a simple Cabibbo-suppression factor of |Vcd/Vcs|2. The small branching fraction could be attributed to a suppression due to the large momentum of the baryonic decay products, which has been observed in other charmed baryonic two-body B decays.