Gamow - Teller Transition Strengths from 56

M. Sasano, G. Perdikakis, R. G. T. Zegers, Sam M. Austin, D. Bazin, B.A. Brown, C. Caesar, A. L. Cole, J.M. Deaven, N. Ferrante, C. J. Guess, G.W. Hitt, R. Meharchand, F. Montes, J. Palardy, A. Prinke, L. A. Riley, H. Sakai, M. Scott, A. Stolz, L. Valdez, and K. Yako National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824-1321, USA Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA GSI Darmstadt, Helmholtz-Zentrum für Schwerionenforschung, D-64291, Darmstadt, Germany Physics Department, Kalamazoo College, Kalamazoo, Michigan 49006, USA Department of Physics and Astronomy, Ursinus College, Collegeville, Pennsylvania 19426, USA Department of Physics, University of Massachusetts Lowell, Lowell, Massachusetts 01854, USA Khalifa University of Science, Technology & Research, 127788 Abu Dhabi, United Arab Emirates RIKEN Nishina Center, Wako, 351-0198, Japan Department of Physics, University of Tokyo, Tokyo, 113-0033, Japan (Received 2 August 2011; published 7 November 2011; publisher error corrected 19 December 2011) A new technique to measure ðp; nÞ charge-exchange reactions in inverse kinematics at intermediate energies on unstable isotopes was successfully developed and used to study the 56Niðp; nÞ reaction at 110 MeV=u. Gamow-Teller transition strengths from Ni leading to Cu were obtained and compared with shell-model predictions in the pf shell using the KB3G and GXPF1A interactions. The calculations with the GXPF1A interaction reproduce the experimental strength distribution much better than the calculations that employed the KB3G interaction, indicating deficiencies in the spin-orbit and protonneutron residual potentials for the latter. The results are important for improving the description of electron-capture rates on nuclei in the iron region, which are important for modeling the late evolution of core-collapse and thermonuclear supernovae.