Evidence for an Excited Hyperon State in pp -> p K^+ Y^{0*}
摘要
Indications for the production of a neutral excited hyperon in the reaction pp -> p K^+ Y^{0*} are observed in an experiment performed with the ANKE spectrometer at COSY-J\"ulich at a beam momentum of 3.65 GeV/c. Two final states were investigated simultaneously, viz. Y^{0*} -> pi^+X^- and pi^-X^+, and consistent results were obtained in spite of the quite different experimental conditions. The parameters of the hyperon state are M(Y^{0*})= (1480 +/- 15) MeV/c^2 and Gamma(Y^{0*})= (60 +/- 15) MeV/c^2. The production cross section is of the order of few hundred nanobarns. Since the isospin of the Y^{0*} has not been determined here, it could either be an observation of the Sigma(1480), a one-star resonance of the PDG tables, or alternatively a Lambda hyperon. Relativistic quark models for the baryon spectrum do not predict any excited hyperon in this mass range and so the Y^{0*} may be of exotic nature.
引用
@article{arxiv.nucl-ex/0506014,
title = {Evidence for an Excited Hyperon State in pp -> p K^+ Y^{0*}},
author = {I. Zychor and V. Koptev and M. Büscher and A. Dzyuba and I. Keshelashvili and V. Kleber and R. Koch and S. Krewald and Y. Maeda and S. Mikirtichyants and M. Nekipelov and H. Ströher and C. Wilkin},
journal= {arXiv preprint arXiv:nucl-ex/0506014},
year = {2008}
}
备注
4 pages, 3 figures, accepted for publication in Phys.Rev.Lett