Search for the resonance-enhanced CP and angular asymmetries in the Λ_c^+→pμ^+ μ^- decay at LHCb

Abstract

The first measurement of the CP asymmetry of the decay rate (A_CP) and the CP average (Sigma A_FB) and CP asymmetry (Delta A_FB) of the forward-backward asymmetry in the muon system of Λ_c^+ -> pμ^+ μ^- decays is reported. The measurement is performed using a data sample of proton-proton collisions, recorded by the LHCb experiment from 2016 to 2018 at a center-of-mass energy of 13 TeV, which corresponds to an integrated luminosity of 5.4 fb^-1. The asymmetries are measured in two regions of dimuon mass near the phi-meson mass peak. The dimuon-mass integrated results are: A_CP = (-1.1 ± 4.0 ± 0.5)% Sigma A_FB = (3.9 ± 4.0 ± 0.6)% Delta A_FB = (3.1 ± 4.0 ± 0.4)% where the first uncertainty is statistical and the second systematic. The results are consistent with the conservation of CP symmetry and the Standard Model expectations.