Baryonic resonances close to the Kbar-N threshold: the case of Sigma(1385)^+ in pp collisions
nucl-ex
/ Authors
G. Agakishiev, A. Balanda, D. Belver, A. V. Belyaev, A. Blanco, M. Boehmer, J. L. Boyard, P. Cabanelas, E. Castro, J. C. Chen
and 92 more authors
S. Chernenko, T. Christ, M. Destefanis, F. Dohrmann, A. Dybczak, E. Epple, T. Eberl, L. Fabbietti, O. V. Fateev, P. Finocchiaro, P. Fonte, J. Friese, I. Froehlich, T. Galatyuk, J. A. Garzon, R. Gernhaeuser, C. Gilardi, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, T. Heinz, T. Hennino, R. Holzmann
/ Abstract
We present results of an exclusive measurement of the first excited state of the Sigma hyperon, Sigma(1385)^+, produced in p+p -> Sigma^+ + K^+ + n at 3.5 GeV beam energy. The extracted data allow to study in detail the invariant mass distribution of the Sigma(1385)^+. The mass distribution is well described by a relativistic Breit-Wigner function with a maximum at m_0 = 1383.2 +- 0.9 MeV/c^2 and a width of 40.2 +- 2.1 MeV/c^2. The exclusive production cross-section comes out to be 22.27 +- 0.89 +- 1.56 +3.07 -2.10 mu b. Angular distributions of the Sigma(1385)^+ in different reference frames are found to be compatible with the hypothesis that 33 % of Sigma(1385)^+ result from the decay of an intermediate Delta^{++} resonance.