G9/2isobaric analogue resonances in the56Fe(p,γ)57Co reaction

Abstract

Resonances consistent with fragmented g9/2 analogue resonance have been found in 57Co corresponding to the Ex=2.454 MeV level in the 57Fe parent nucleus. The resonance was located through the 56Fe(p, gamma )57Co reaction. Total gamma -ray spectra were measured with a Ge(Li) detector in 2 keV steps in the expected proton energy range. Excitation functions for the different primary gamma transitions were constructed. The g9/2 IAR were found in two components at Ep=3728 and 3735 keV. The angular distributions of gamma rays were measured at these two bombarding proton energies. The two resonances were suggested to have spin and parity Jpi =9/2+ based on the gamma -ray excitation functions and angular distribution measurements. The gamma -branchings and absolute transition probabilities were also determined. The Ml gamma transitions from the g9/2 IAR components going to the possible anti-analogue level at Ex=4.585 MeV excitation energy have absolute transition strengths of 1.8*10-2 Wu and 1.2*10-2 Wu.