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.

Aaij, R., Abdelmotteleb, A., Abellan Beteta, C., Abudinen, F., Ackernley, T., Adefisoye, A., et al. (2025). Observation of the Very Rare Σ^{+}→pμ^{+}μ^{-} Decay. PHYSICAL REVIEW LETTERS, 135(5) [10.1103/r3v2-kmmp].

Observation of the Very Rare Σ^{+}→pμ^{+}μ^{-} Decay

Anelli A.;Borsato M.;Calvi M.;Capelli S.;Carniti P.;Fazzini D.;Garcia Pardinas J.;Kirsebom V. S.;Malentacca L.;Martinazzoli L.;Martinelli M.;Minotti A.;Pizzichemi M.;Salomoni M.;
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.
Articolo in rivista - Articolo scientifico
proton-proton collision
English
29-lug-2025
2025
135
5
051801
none
Aaij, R., Abdelmotteleb, A., Abellan Beteta, C., Abudinen, F., Ackernley, T., Adefisoye, A., et al. (2025). Observation of the Very Rare Σ^{+}→pμ^{+}μ^{-} Decay. PHYSICAL REVIEW LETTERS, 135(5) [10.1103/r3v2-kmmp].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/579193
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