Measurement of weak rates for stellar evolution via the (t,He-3)reaction.

摘要

The (t,He-3) charge-exchange reaction has been developed as a tool to extract Gamow-Teller strengths on nuclei of importance for stellar evolution. A secondary triton beam of 115 MeVucleon is used, either produced from a primary a beam, or, since recently, from a primary O-16 beam. Here, the (t,He-3) reaction is used to study the Garnow-Teller strength distribution in Co-58 via the Ni-58 (t,He-3) reaction. The experimental results are compared with calculations in large-scale shell models using the kb3g and gxpfl interactions, as well as existing data from Ni-58(n,p) and Ni-58(d,He-2) experiments. The differences between the data and theoretical models are studied in terms of electron-capture rates in the pre-collapse stages of core-collapse supernovae.