Single-particle shell strengths near the doubly magic nucleus 56Ni and the 56Ni( p, γ) 57Cu reaction rate in explosive astrophysical burning

摘要

Angle-integrated cross-section measurements of the56Ni(d,n) and (d,p) stripping reactions have been performed to determine the single-particle strengths of low-lying excited states in the mirror nuclei pair57Cu?57Ni situated adjacent to the doubly magic nucleus56Ni. The reactions were studied in inverse kinematics utilizing a beam of radioactive56Ni ions in conjunction with the GRETINAγ-array. Spectroscopic factors are compared with new shell-model calculations using a fullpfmodel space with the GPFX1A Hamiltonian for the isospin-conserving strong interaction plus Coulomb and charge-dependent Hamiltonians. These results were used to set new constraints on the56Ni(p,γ)57Cu reaction rate for explosive burning conditions in x-ray bursts, where56Ni represents a key waiting point in the astrophysicalrp-process.