First Observation of the Charmless Baryonic Decay B+ → (Λ)over-barp(p)over-barp



Aaij, R, Abdelmotteleb, ASW, Beteta, C Abellan, Abudinen, F, Ackernley, T, Adefisoye, AA, Adeva, B, Adinolfi, M, Adlarson, P, Agapopoulou, C
et al (show 1177 more authors) (2025) First Observation of the Charmless Baryonic Decay B+ → (Λ)over-barp(p)over-barp PHYSICAL REVIEW LETTERS, 135 (26). 261901-. ISSN 0031-9007, 1079-7114

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Abstract

A search for the charmless baryonic decay B+→Λ¯pp¯p is performed using proton-proton collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 5.4 fb-1. The branching fraction for this decay is measured for the first time relative to that of the topologically similar decay B+→J/ψK+, with J/ψ→Λ¯pK-. The branching fraction is measured to be B(B+→Λ¯pp¯p)=(2.15±0.35±0.12±0.28)×10-7, where the first uncertainty is statistical, the second is systematic, and the third arises from the uncertainty in the normalization channel branching fraction. The CP asymmetry is measured to be ACP=(5.4±15.6±2.4)%, where the uncertainties are statistical and systematic. The background-subtracted invariant-mass distributions of Λ¯p and p¯p pairs exhibit pronounced enhancements at both kinematic thresholds, in contrast to a uniform phase-space distribution.

Item Type: Article
Uncontrolled Keywords: LHCb Collaboration
Divisions: Faculty of Science & Engineering
Faculty of Science & Engineering > School of Engineering
Faculty of Science & Engineering > School of Physical Sciences
Faculty of Science & Engineering > School of Physical Sciences > Physics
Faculty of Science & Engineering > School of Engineering > Civil and Environmental Engineering
Depositing User: Symplectic Admin
Date Deposited: 05 Jan 2026 09:45
Last Modified: 16 Jun 2026 20:26
DOI: 10.1103/3pcs-dxtn
Open Access URL: https://journals.aps.org/prl/pdf/10.1103/3pcs-dxtn
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3196393
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