Fusion Hindrance and Quadrupole Collectivity in Collisions of A≃50 Nuclei: The Case of ⁴⁸Ti + ⁵⁸Fe

¹ NFN, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Padova), Italy
² Dipartimento di Fisica e Astronomia, Università di Padova, and INFN, Sezione di Padova, I-35131 Padova, Italy
³ IPHC, CNRS-IN2P3, Université de Strasbourg, F-67037 Strasbourg Cedex 2, France
⁴ CSNSM, CNRS/IN2P3 and Université Paris-Sud, F-91405 Orsay Campus, France
⁵ Institute of Nuclear Physics, Polish Academy of Sciences, PL 31-342 Cracow, Poland
⁶ Ruđer Bošković Institute, HR-10002 Zagreb, Croatia

^a e-mail: alberto.stefanini@lnl.infn.it

Published online: 29 January 2015

Abstract

The fusion excitation function of ⁴⁸Ti + ⁵⁸Fe has been measured in a wide energy range around the Coulomb barrier, covering 6 orders of magnitude of the cross sections. We present here the preliminary results of this experiment, and a full comparison with the near-by system ⁵⁸Ni + ⁵⁴Fe where evidence of fusion hindrance shows up at relatively high cross sections. The sub-barrier cross sections of ⁴⁸Ti + ⁵⁸Fe are much larger than those of ⁵⁸Ni + ⁵⁴Fe. Significant differences are also observed in the logarithmic derivatives, astro-physical S-factors and fusion barrier distributions. The influence of low-energy nuclear structure on all these trends is pointed out and commented. Coupled-channels calculations using a Woods-Saxon potential are able to reproduce the experimental results for ⁴⁸Ti + ⁵⁸Fe. The logarithmic derivative of the excitation function is very nicely fit, and no evidence of hindrance is observed down to around 1 μb. The fusion barrier distribution is rather wide, flat and structureless. It is only in qualitative agreement with the calculated distribution.