Observation of the decay B0bar -> LambdaC antiproton pi0

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