High resolution studies of low lying GT strength using the (d,He-2) reaction and its impact on electron-capture rates in stellar environments

Abstract Gamow-Teller transitions in fp-shell nuclei have been studied using the 58 Ni( d , 2 He) charge exchange reaction at an incident energy of 170 MeV and forward angles. The measurements have been performed at AGOR using the Big-Bite Spectrometer and the EuroSuperNova focal-plane detection system. The unprecedented energy resolution of about 130 keV FWHM for excitations in the residual nucleus 58 Co allowed for the first time the extraction of single transitions in the β + direction up to about 4 MeV excitation. The impact on electron-capture rates in astrophysical environments has been evaluated.