Observation of the photoproduction of a
pair of charmed mesons
Adamovich M. I., Aleksandrov Yu. A., Bolta J. M., Bravo L., Cartacci A. M., Chernyavskii M. N., Conforto B., Conti A., Crosetti G., Dagliana M. G., Dameri M., Giambrini-Palazzi G., Caporiacco G. D., Forino A., Gessaroli R., Higon E., Kharlamov S. P., Larionova V. G., Llosa J. A., Lory J., Mattel A., Orlova G. I., Osculati B., Parrini G., Peresad'ko N. G., Quareni A., Ruiz A., Romanovskaya K. M., Sanchez M. A., Sannino M., Schune D., Tentindo S., Tomasini G., Tret'yakova M. I., Chue Tsai, Vanderhaeghe G., Villar E., Willot B., Atkinson M., Brodbeck T., Brookes G. R., Bussey P. J., Davenport M., Dufey J. -P., Elison R. J., Galbraith W., Heinloth K., Mutton J., Hughes-Jones R. E., Ibbotson M., Kumar R., Lafferty G. D., Lane J. B., Lasalle J. -C., McClatchey R., Mercer D., Morris J. V., Storr K. M., Waite A. P.
An interesting event has been observed in an experiment on the production of charmed particles by tagged photons from the CERN supersynchrotron. The event was detected simultaneously in a nuclear emulsion and by the Omega Prime magnetic spectrometer. It is interpreted as the firstobserved case of the photoproduction of a pair of charmed neutral mesons, D°D°. A decay time r(D°) = (0.14±0.01).10-13 s has been found for the decay ð_°-^ë+7Ç^~ÔÇ+Õ while two solutions have been found for the decay D°-+K°K~e+v: τ γ(Ώ °) = (3.4±0.3)ž10-13 s and r2(D°) = (7.5±0.3)ž1(>-13 s.