Is the Sigma-nucleus potential for Sigma(-) atoms consistent with the Si-28(pi(-), K+) data?

摘要

In order to examine whether the Sigma-nucleus potential for Sigma(-) atoms can explain the experimental (pi(-), K+) data or not, we evaluate Sigma(-) hypernuclear production by the (pi(-), K+) reaction on a (28)si target, in the framework of a distorted-wave impulse approximation with an optimal Fermi-averaging for the elementary pi(-) + p -> K+ + Sigma(-) t-matrix. Inclusive K+ spectra of the Si-28(pi(-), K+) reaction are calculated with several E-nucleus (optical) potentials for Sigma(-)-Al-27 which are determined by fits to the Sigma- atomic X-ray data, and the properties of these potentials are tested in detail by comparing the calculated spectra with the (pi(-) K+) experimental data at KEK. The results show that the potentials having a repulsion inside the nuclear surface and an attraction outside the nucleus with a sizable absorption, can reproduce the Si-28(pi(-), K+) data very well; the optimal Fermi-averaging for the pi(-) + P -> K+ + Sigma(-) reaction also gives a good description of the energy-dependence in the Sigma(-) quasi-free spectrum. This is the first successful attempt to explain simultaneously the Sigma-atomic X-ray data and the (pi(-), K+) reaction. (c) 2005 Elsevier B.V. All rights reserved.