Evidence for the two-body charmless baryonic decay {B}+\to p\overline{Λ}

Abstract

A search for the rare two-body charmless baryonic decay {B}+\to p\overline{Λ} is performed with pp collision data, corresponding to an integrated luminosity of 3 fb-1, collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. An excess of {B}+\to p\overline{Λ} candidates with respect to background expectations is seen with a statistical significance of 4.1 standard deviations, and constitutes the first evidence for this decay. The branching fraction, measured using the B + → K S 0 π + decay for normalisation, is {B}({B}+\to p\overline{Λ})=(2.{4}_{-0.8}^{+1.0}± 0.3)× 1{0}^{-7}, where the first uncertainty is statistical and the second systematic.