6 research outputs found
Discovery of naked charm particles and lifetime differences among charm species using nuclear emulsion techniques innovated in Japan
This is a historical review of the discovery of naked charm particles and lifetime differences among charm species. These discoveries in the field of cosmic-ray physics were made by the innovation of nuclear emulsion techniques in Japan. A pair of naked charm particles was discovered in 1971 in a cosmic-ray interaction, three years prior to the discovery of the hidden charm particle, J/Ξ¨, in western countries. Lifetime differences between charged and neutral charm particles were pointed out in 1975, which were later re-confirmed by the collaborative Experiment E531 at Fermilab. Japanese physicists led by K.Niu made essential contributions to it with improved emulsion techniques, complemented by electronic detectors. This review also discusses the discovery of artificially produced naked charm particles by us in an accelerator experiment at Fermilab in 1975 and of multiple-pair productions of charm particles in a single interaction in 1987 by the collaborative Experiment WA75 at CERN
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Analysis of 303-GeV/c Proton Interactions Tagged by High-Energy Gamma rays
Two emulsion chambers of sandwich type of nuclear emulsion and thin lead plates were exposed to 303 GeV/c proton beams at the Fermi National Accelerator Laboratory. 70 jet showers tagged by high energy {gamma} rays were analyzed and correlations between high energy {gamma} rays and charged particles with large transverse momenta were studied. Strong correlation was observed between these components and a possible explanation for this effect may be the formation of a forward excited baryon and its decay. A special event with a direct electron was also observed