Investigation of the decay of charmed particles produced in neutrino interactions

Abstract The decay of charmed particles produced by high-energy neutrinos has been studied by an experiment using simultaneously emulsion, bubble chamber and counter techniques. Eight charmed particle candidates, 5 positively charged and 3 neutral, have been found in the emulsion, where their production and decay have been directly observed. One of these events is identified as a Λ c + baryon of mass 2.26±0.02 GeV/ c 2 which undergoes the decay Λ c + →pK − π + after a proper time of (7.3±0.1) · 10 −13 s. A statistical analysis of the other observed decays leads to the mean-life values τ + =(2.5 −1.1 +2.2 ) · 10 −13 s, τ 0 =(0.53 −0.25 +0.57 ) · 10 −13 s, for the sample of charged particles enriched by a similar event found in a previous experiment, and for the sample of 3 neutral particles, respectively. The former value is only slightly affected by including in the sample the Λ c + event or excluding that of the previous experiment.