- th / 0 70 10 21 v 1 9 J an 2 00 7 The role of ∆ + + ∗ ( 1620 ) resonances in pp → nK + Σ + reaction and its important implications
نویسنده
چکیده
The pp → nK+Σ+ reaction is a very good isospin 3/2 filter for studying ∆++∗ decaying to K+Σ+. With an effective Lagrangian approach, contributions from a previous ignored sub-K+Σ+-threshold resonance ∆++∗(1620)1/2− are fully included in addition to those already considered in previous calculations. It is found that the ∆++∗(1620)1/2− resonance gives an overwhelmingly dominant contribution for energies very close to threshold, with a very important contribution from the t-channel ρ exchange. This solves the problem that all previous calculations seriously underestimate the near-threshold cross section by order(s) of magnitude. Many important implications of the results are discussed. PACS: 13.75.Cs.; 14.20.Gk.; 13.30.Eg.
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