TY - JOUR
T1 - Observation of the Rare Baryonic Decay B+ →p Λ ¯ and Measurement of its Weak Decay Parameter
AU - (LHCb Collaboration)
AU - Aaij, R.
AU - Abdelmotteleb, A. S.W.
AU - Abellan Beteta, C.
AU - Abudinén, F.
AU - Ackernley, T.
AU - Adefisoye, A. A.
AU - Adeva, B.
AU - Adinolfi, M.
AU - Adlarson, P.
AU - Agapopoulou, C.
AU - Aidala, C. A.
AU - Ajaltouni, Z.
AU - Akar, S.
AU - Akiba, K.
AU - Albicocco, P.
AU - Albrecht, J.
AU - Aleksiejunas, R.
AU - Alessio, F.
AU - Alvarez Cartelle, P.
AU - Amalric, R.
AU - Amato, S.
AU - Amey, J. L.
AU - Amhis, Y.
AU - An, L.
AU - Anderlini, L.
AU - Andersson, M.
AU - Andreola, P.
AU - Andreotti, M.
AU - Andres Estrada, S.
AU - Anelli, A.
AU - Ao, D.
AU - Arata, C.
AU - Archilli, F.
AU - Areg, Z.
AU - Argenton, M.
AU - Arguedas Cuendis, S.
AU - Arnone, L.
AU - Artamonov, A.
AU - Artuso, M.
AU - Aslanides, E.
AU - Ataíde Da Silva, R.
AU - Atzeni, M.
AU - Audurier, B.
AU - Authier, J. A.
AU - Bacher, D.
AU - Bachiller Perea, I.
AU - Bachmann, S.
AU - Balagura, V.
AU - Fleuret, F.
AU - Maurice, E.
N1 - Publisher Copyright:
© 2026 CERN.
PY - 2026/2/6
Y1 - 2026/2/6
N2 - 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.
AB - 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.
UR - https://www.scopus.com/pages/publications/105029432496
U2 - 10.1103/fj4q-t8jg
DO - 10.1103/fj4q-t8jg
M3 - Article
AN - SCOPUS:105029432496
SN - 0031-9007
VL - 136
JO - Physical Review Letters
JF - Physical Review Letters
IS - 5
M1 - 051802
ER -