Evidence for an Excited Hyperon State in pp-&gt;pK+Y0*

Zychor, I.; Krewald, S.; Keshelashvili, I.; Nekipelov, M.; Ströher, H.; Wilkin, C.; Maeda, Y.; Kleber, V.; Koptev, V.; Mikirtichyants, S.; Dzyuba, A.; Koch, H. R.; Büscher, M.

doi:10.1103/PhyRevLett.96.012002

Journal Article

Evidence for an Excited Hyperon State in pp->pK+Y0*

Zychor, I. ; Koptev, V. ; Büscher, M.FZJ* ; Dzyuba, A. ; Keshelashvili, I.FZJ* ; Kleber, V. ; Koch, H. R.FZJ* ; Krewald, S.FZJ* ; Maeda, Y.FZJ* ; Mikirtichyants, S. ; Nekipelov, M.FZJ* ; Ströher, H.FZJ* ; Wilkin, C.

2006
APS College Park, Md.

Physical review letters 96, 012002 (2006) [10.1103/PhyRevLett.96.012002]

This record in other databases:

Please use a persistent id in citations: http://hdl.handle.net/2128/1639 doi:10.1103/PhyRevLett.96.012002

Abstract: Indications for the production of a neutral excited hyperon in the reaction pp -> pK(+)Y(0*) are observed in an experiment performed with the ANKE spectrometer at COSY-Julich at p(beam)=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 for Y-0* decaying through these channels 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 Particle Data Group 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.

Keyword(s): J

Classification: