Search for B−→Λ¯pν¯ν with the BaBar experiment

Abstract

A search for the rare flavor-changing neutral current process B − → Λ ¯ p ν ¯ ν using data from the BABAR experiment has been performed. A total of 424 fb − 1 of e + e − collision data collected at the center-of-mass energy of the Υ ( 4 S ) resonance is used in this study, corresponding to a sample of ( 471 ± 3 ) × 10 6 B ¯ B pairs. Signal B − → Λ ¯ p ν ¯ ν candidates are identified by first fully reconstructing a B + decay in one of many possible exclusive decays to hadronic final states, then examining detector activity that is not associated with this reconstructed B + decay for evidence of a signal B − → Λ ¯ p ν ¯ ν decay. The data yield is found to be consistent with the expected background contribution under a null signal hypothesis, resulting in an upper limit of B ( B − → Λ ¯ p ν ¯ ν ) < 3.0 × 10 − 5 at the 90% confidence level.