Decay rate and asymmetries of Σ+ → pμ+μ

• Published in: The journal of high energy physics Vol. 2018; no. 10; pp. 1 - 20
• Main Authors: He, Xiao-Gang, Tandean, Jusak, Valencia, German
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.10.2018; Springer Nature B.V; SpringerOpen
• Subjects: Asymmetry; Beyond Standard Model; Chiral Lagrangians; Classical and Quantum Gravitation; Decay rate; Effective Field Theories; Elementary Particles; High energy physics; Nonperturbative Effects; Parameterization; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Regular Article - Theoretical Physics; Relativity Theory; Standard model (particle physics); String Theory; Uncertainty; Chiral Lagrangians; Effective Field Theories; Beyond Standard Model; Nonperturbative Effects
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP10(2018)040

A bstract The LHCb Collaboration has recently reported evidence for the rare hyperon decay Σ + → pμ + μ − that is consistent with the standard model expectation. Motivated by this new result we revisit the calculation of this mode including both long and short distance contributions. In the standard model this mode is completely dominated by long distance physics and thus subject to large uncertainties. We present a range of predictions for the rate, the dimuon invariant mass spectrum, and a muon polarization asymmetry that covers these uncertainties as well as known constraints. We study the interplay between short and long distance contributions which could result in additional asymmetries, but we find that they are negligible within the standard model. We propose a parameterization of these asymmetries in terms of a couple of constants that can arise from new physics.