Observation of the Production of Short-Lived Particles in a High-Resolution Streamer-Chamber Experiment

Abstract
Short-lived particles produced in association with muons have been observed in the interactions of 350-GeV/c protons with neon in a high-resolution streamer chamber. The characteristics of these events are consistent with the expected properties of charmed particles if the average lifetime lies between 1013 and 2×1012 sec. With the assumption that the observed events are mainly D± mesons with lifetimes of approximately 1012 sec, the production cross section is estimated to lie between 20 and 50 μb per nucleon.