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Title: | Search for the rare decay Λc+ →pμ+μ- |
Author: | Alfonso Albero, Alejandro Calvo Gomez, M. Camboni, Alessandro Coquereau, Samuel Garrido Beltrán, Lluís Gascón Fora, David Graugés Pous, Eugeni Marin Benito, Carla LHCb Collaboration |
Keywords: | Hadrons Gran Col·lisionador d'Hadrons Física de partícules Experiments Hadrons Large Hadron Collider (France and Switzerland) Particle physics Experiments |
Issue Date: | 2018 |
Publisher: | American Physical Society |
Abstract: | The flavor-changing neutral-current (FCNC) decay Λþ c → pμþμ− (inclusion of the charge-conjugate processes is implied throughout) is expected to be heavily suppressed in the Standard Model (SM) by the Glashow-IliopoulosMaiani mechanism [1]. The branching fractions for shortdistance c → ulþl− contributions to the transition are expected to be of Oð10−9Þ in the SM but can be enhanced by effects beyond the SM. However, long-distance contributions proceeding via a tree-level amplitude, with an intermediate meson resonance decaying into a dimuon pair [2,3], can increase the branching fraction up to Oð10−6Þ [4]. The short-distance and hadronic contributions can be separated by splitting the data set into relevant regions of dimuon mass. The Λþ c → pμþμ− decay has been previously searched for by the BABAR Collaboration [5], yielding 11.1 5.0 2.5 events and an upper limit on the branching fraction of 4.4 × 10−5 at 90% C.L. Similar FCNC transitions for the b-quark system (b → slþl−) exhibit a pattern of consistent deviations from the current SM predictions both in branching fractions [6] and angular observables [7], with the combined significance reaching 4 to 5 standard deviations [8,9]. Processes involving c → ulþl− transitions are far less explored at both the experimental and theoretical levels, which makes such measurements desirable. Similar analyses of the D system have reported evidence for the longdistance contribution [10]; however, the short-distance contributions have not been established [11]. |
Note: | Reproducció del document publicat a: https://doi.org/10.1103/PhysRevD.97.091101 |
It is part of: | Physical Review D, 2018, vol. 97, num. 9, p. 1-10 |
URI: | http://hdl.handle.net/2445/185388 |
Related resource: | https://doi.org/10.1103/PhysRevD.97.091101 |
ISSN: | 2470-0010 |
Appears in Collections: | Articles publicats en revistes (Física Quàntica i Astrofísica) |
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