Repulsion and absorption of the Σ-nucleus potential for Σ⁻-⁵He in the ⁶Li(π⁻, K⁺) reaction

We study phenomenologically inclusive spectra of the ⁶Li(π⁻, K⁺) reaction at 1.2 GeV/c within a distorted-wave impulse approximation with the optimal Fermi-averaging π⁻p → K⁺Σ⁻ t matrix. We attempt to clarify the property of a Σ-nucleus potential for Σ⁻-⁵He by comparing the calculated spectra with the data of the J-PARC E10 experiment. The result shows that the repulsive and absorptive components of the Σ⁻-⁵He potential provide the ability to explain the data of the continuum spectra in Σ and Λ regions; the strengths of V_Σ ≃ +30 MeV and W_Σ ≃ −26 MeV are favored within the Woods-Saxon potential, consistent with analyses for heavier nuclei. Effects of the size and potential range for Σ⁻-⁵He in the neutron excess of (N − Z)/(N + Z) = 0.2 are also discussed.