The first observation of the ς+→pμ+μ- decay is reported with high significance using proton-proton collision data, corresponding to an integrated luminosity of 5.4 fb-1, collected with the LHCb detector at a center-of-mass energy of 13 TeV. A yield of 237±16 ς+→pμ+μ- decays is obtained, where the uncertainty is statistical only. A branching fraction of (1.08±0.17)×10-8 is measured, where the uncertainty includes statistical and systematic sources. No evidence of resonant structures is found in the dimuon invariant-mass distribution. All results are compatible with standard model expectations. This represents the rarest decay of a baryon ever observed.

Observation of the Very Rare Σ+→pμ+μ− Decay / R. Aaij, A. . .A.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 135:5(2025 Jul 29), pp. 051801.1-051801.14. [10.1103/r3v2-kmmp]

Observation of the Very Rare Σ+→pμ+μ− Decay

S. Cesare;C. Mancuso;D. Marangotto;N. Neri;G. Tonani;T. Tork;Z. Wang;
2025

Abstract

The first observation of the ς+→pμ+μ- decay is reported with high significance using proton-proton collision data, corresponding to an integrated luminosity of 5.4 fb-1, collected with the LHCb detector at a center-of-mass energy of 13 TeV. A yield of 237±16 ς+→pμ+μ- decays is obtained, where the uncertainty is statistical only. A branching fraction of (1.08±0.17)×10-8 is measured, where the uncertainty includes statistical and systematic sources. No evidence of resonant structures is found in the dimuon invariant-mass distribution. All results are compatible with standard model expectations. This represents the rarest decay of a baryon ever observed.
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
29-lug-2025
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/1251475
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