open access

https://hdl.handle.net/2115/90314

Production spectra with a Sigma(-) hyperon in ( pi(-), K (+)) reactions on light to heavy nuclei

英語

2023-05-19

American Physical Society (APS)

Physical Review C

107(5)

054611-1-054611-20

We study theoretically production spectra with a Sigma (-) hyperon via ( pi(-), K (+)) reactions on C-12, Si-28, Ni-58, In-115, and Bi-209 targets, using the Green's function method in the framework of a distorted-wave impulse approximation with the optimal Fermi averaging for an elementary pi- p -> K + Sigma(-) t matrix. Adopting distorted waves obtained by solving a Klein-Gordon equation for pi(-) and K+ mesons, we improve and update the calculated spectra of Sigma(-) production cross sections comprehensively in comparison with the data of the KEK-E438 experiment. We use several Sigma(-)nucleus (optical) potentials that are determined by fits to the Sigma(-) atomic data and that take into account the energy dependence arising from the nuclear excitation via Sigma N -> Sigma N scatterings with a Sigma hyperon effective mass. The results show that the absolute values and the shapes of these calculated spectra are in excellent agreement with those of the data, so that a mass-number dependence of integrated cross sections on the light-to-heavy targets is well reproduced in our calculations. It confirms that the Sigma-nucleus potentials having a repulsion inside the nuclear surface and an attraction outside the nucleus with a sizable absorption are favored in reproducing the data of the nuclear ( pi(-), K (+)) spectra and the Sigma- atomic x ray simultaneously, whereas it is still difficult to determine the radial distribution of the Sigma(-)nucleus potential inside the nucleus and its strength at the center.

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