Nuclear-emulsion observation of the decay of a charmed Σc0 baryon Λc+π- followed by a Λc+ decay into Σ+π-π+
Ammar R. G., Ammosov V. V., Bakic A., Baranov V. I., Burnett T. H., Batusov Yu. A., Bunyatov S. A., Vaisenberg A. O., Wilkes R. J., Wilczinska B., Wilczinski G., Voyvodic L., Walter W., Wojczek B., Gapienko V.A., Gorichev P. A., Grass J., Daion M. I., Davis R. E. P., Egorov O. K., Ivanova M., Kwak N.,. Klyukhin V. I, Kolganova E. D., Koppage D., Koreshev V. I., Krziwdzinski S., Kuznetsov O. M., Lord J. J., Lyukov V. V., Makhlyueva I. V., Olshevski A. G., Pick L., Pitukhin P. V., Pozharova E. A., Reimer R., Rappoport V. M., Rosenbladt R., Rubin H. A., Sipotenko V. I., Slobodyuk E. A., Smart W., Smirnitskii V. A., Stump R., Tret'yak V. I., Chernev H., Shamanov V. V., Shevchenko V. G., Jurak A., Yarba V. A.

An event in which the decay of a charmed Σ° baryon into Лс+ and тг~ has been detected in a neutrino experiment with a nuclear emulsion is described. The decay of the Лс+ baryon occurs in the channel Лс+ —>Σ+π~π+ with an observable subsequent decay of Σ+^>π+η. The mass of the Лс+ is 2.300 + 0.025 GeV/c2, and it decays in a time of (3.13 + 0.02) χ 10""13 s. The mass of the Σ° baryon and the difference between the Σ° and Лс+ masses are 2.462 ± 0.026 GeV/c2 and 0.163 + 0.002 GeV/c2, respectively.