학술논문

Evidence for the Rare Decay Σ^{+}→pμ^{+}μ^{-}.
Document Type
article
Source
Physical review letters. 120(22)
Subject
LHCb Collaboration
Intellectual and Developmental Disabilities (IDD)
Brain Disorders
Down Syndrome
hep-ex
General Physics
Mathematical Sciences
Physical Sciences
Engineering
Language
Abstract
A search for the rare decay Σ^{+}→pμ^{+}μ^{-} is performed using pp collision data recorded by the LHCb experiment at center-of-mass energies sqrt[s]=7 and 8 TeV, corresponding to an integrated luminosity of 3  fb^{-1}. An excess of events is observed with respect to the background expectation, with a signal significance of 4.1 standard deviations. No significant structure is observed in the dimuon invariant mass distribution, in contrast with a previous result from the HyperCP experiment. The measured Σ^{+}→pμ^{+}μ^{-} branching fraction is (2.2_{-1.3}^{+1.8})×10^{-8}, where statistical and systematic uncertainties are included, which is consistent with the standard model prediction.