Observation of the decay B0bar -> LambdaC antiproton pi0

Abstract

In a sample of 467 million $B\overline{B}$ pairs collected with the BABAR detector at the PEP-II collider at SLAC we have observed the decay ${\overline{B}}^0\to {\Lambda }_c^{+}\overline{p}{\pi }^0$ and measured the branching fraction to be $(1.94\pm 0.17\pm 0.14\pm 0.50)\times 10^{-4}$, where the uncertainties are statistical, systematic, and the uncertainty on the ${\Lambda }_c^{+}\to p{K}^{-}{\pi }^{+}$ branching fraction, respectively. We determine an upper limit of $1.5\times 10^{-6}$ at $90\%$ C.L. for the product branching fraction $\mathcal{B}({\overline{B}}^0\to {\Sigma }_c^{+}(2455)\overline{p})\times \mathcal{B}({\Lambda }_c^{+}\to p{K}^{-}{\pi }^{+})$. Furthermore, we observe an enhancement at the threshold of the invariant mass of the baryon-antibaryon pair.

7 pages, 5 postscript figures, submitted to PRD RC