The first observation of the decay B+→pΛ¯ is presented using proton-proton collision data collected by the LHCb experiment between 2016 and 2018 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb-1. The signal significance exceeds seven standard deviations. Using the B+→KS0π+ decay as a normalization channel, the branching fraction is measured and combined with previous LHCb results based on data collected at 7 and 8 TeV in 2011 and 2012, yielding B(B+→pΛ¯)=(1.24±0.17±0.05±0.03)×10-7, where the first uncertainty is statistical, the second is systematic, and the third comes from the uncertainty on the branching fraction of the normalization channel. The B+→pΛ¯ weak decay parameter is measured to be αB=0.87-0.29+0.26±0.09, indicating the presence of comparable S-wave and P-wave decay amplitudes.

Observation of the Rare Baryonic Decay B + → p Λ ¯ and Measurement of its Weak Decay Parameter / R. Aaij, A. . .A.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 136:5(2026 Feb 06), pp. 051802.1-051802.14. [10.1103/fj4q-t8jg]

Observation of the Rare Baryonic Decay B + → p Λ ¯ and Measurement of its Weak Decay Parameter

S. Cesare;C. Mancuso;D. Marangotto;N. Neri;G. Tonani;T. Tork;Z. Wang;
2026

Abstract

The first observation of the decay B+→pΛ¯ is presented using proton-proton collision data collected by the LHCb experiment between 2016 and 2018 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb-1. The signal significance exceeds seven standard deviations. Using the B+→KS0π+ decay as a normalization channel, the branching fraction is measured and combined with previous LHCb results based on data collected at 7 and 8 TeV in 2011 and 2012, yielding B(B+→pΛ¯)=(1.24±0.17±0.05±0.03)×10-7, where the first uncertainty is statistical, the second is systematic, and the third comes from the uncertainty on the branching fraction of the normalization channel. The B+→pΛ¯ weak decay parameter is measured to be αB=0.87-0.29+0.26±0.09, indicating the presence of comparable S-wave and P-wave decay amplitudes.
Settore PHYS-01/A - Fisica sperimentale delle interazioni fondamentali e applicazioni
   European Particle physics Latin American NETwork
   EPLANET
   European Commission
   SEVENTH FRAMEWORK PROGRAMME - SP3-People - Marie-Curie Actions
   246806
6-feb-2026
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/1250736
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