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.

Aaij, R., Abdelmotteleb, A., Abellan Beteta, C., Abudinen, F., Ackernley, T., Adefisoye, A., et al. (2026). Observation of the Rare Baryonic Decay B+ →p Λ ¯ and Measurement of its Weak Decay Parameter. PHYSICAL REVIEW LETTERS, 136(5) [10.1103/fj4q-t8jg].

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

Anelli A.;Borsato M.;Calvi M.;Capelli S.;Carniti P.;Falcao L. N.;Fazzini D.;Garcia Pardinas J.;Gotti C.;Kirsebom V. S.;Malentacca L.;Martinazzoli L.;Martinelli M.;Minotti A.;Moro A.;Pizzichemi M.;Salomoni M.;
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.
Articolo in rivista - Articolo scientifico
Hadrons; Flavour Physics; Baryons;
English
6-feb-2026
2026
136
5
051802
none
Aaij, R., Abdelmotteleb, A., Abellan Beteta, C., Abudinen, F., Ackernley, T., Adefisoye, A., et al. (2026). Observation of the Rare Baryonic Decay B+ →p Λ ¯ and Measurement of its Weak Decay Parameter. PHYSICAL REVIEW LETTERS, 136(5) [10.1103/fj4q-t8jg].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/593143
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