Challenging fission dynamics around the barrier: The case of 34S + 186W

E. M. Kozulin; E. Vardaci; I. M. Harca; C. Schmitt; I. Itkis; G. Knyazheva; K. Novikov; A. Bogachev; S. Dmitriev; T. Loktev; F. Azaiez; I. Matea; D. Verney; A. Gottardo; O. Dorvaux; J. Piot; G. Chubarian; W. H. Trzaska; F. Hanappe; C. Borcea; S. Calinescu; C. Petrone

doi:10.1140/epja/i2016-16293-8

2022 Impact factor 2.7

Hadrons and Nuclei

Eur. Phys. J. A (2016) 52: 293
https://doi.org/10.1140/epja/i2016-16293-8

Regular Article - Experimental Physics

Challenging fission dynamics around the barrier: The case of ³⁴S + ¹⁸⁶W

E. M. Kozulin¹, E. Vardaci², I. M. Harca¹^,9^,10^*, C. Schmitt³, I. Itkis¹, G. Knyazheva¹, K. Novikov¹, A. Bogachev¹, S. Dmitriev¹, T. Loktev¹, F. Azaiez⁴, I. Matea⁴, D. Verney⁴, A. Gottardo⁴, O. Dorvaux⁵, J. Piot³, G. Chubarian⁶, W. H. Trzaska⁷, F. Hanappe⁸, C. Borcea⁹, S. Calinescu⁹ and C. Petrone⁹

¹ Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Dubna, Russia
² Dipartamento di Scienze Fisiche and INFN (INFN-Na), Napoli, Italy
³ GANIL, CEA/DSM-CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076, Caen, France
⁴ IPN, CNRS/IN2P3, Université Paris-Saclay, 91405, Orsay, France
⁵ IPHC, CNRS/IN2P3, Université de Strasbourg, 67037, Strasbourg, France
⁶ Cyclotron Institute, Texas A & M University, 77843-3366, College Station, TX, USA
⁷ Accelerator Laboratory of University of Jyvaskyla (JYFL), Jyvaskyla, Finland
⁸ Université Libre de Bruxelles (ULB), Bruxelles, Belgium
⁹ Horia Hulubei National Institute for R & D in Physics and Nuclear Engineering (IFIN-HH), Bucharest - Magurele, Romania
¹⁰ Facultatea de Fizica, Universitatea din Bucuresti, Bucharest, Romania

^* e-mail: harca@jinr.ru

Received: 16 June 2016
Accepted: 6 August 2016
Published online: 22 September 2016

Abstract

The current status of fission dynamics studies in heavy-ion collisions around the Coulomb barrier is illustrated with the ³⁴S + ¹⁸⁶W reaction. The fission-fragment mass and total kinetic energy were measured at the ALTO facility at IPN Orsay, France, with a dedicated set-up using the (v, E) approach. The measurement reveals the presence of an asymmetric fission component on top of a predominantly symmetric distribution. The asymmetric structure, pointed out for the first time, is discussed along with results of previous experiments studying the same reaction. While these analyses suggested the contribution from either quasi-fission or pre-equilibrium fission, we offer an alternative interpretation, in terms of shell-driven compound-nucleus fission. The present measurement demonstrates the critical influence of resolution when addressing puzzling cases, situated at the crossroads of the various channels opened in a heavy-ion collision. Current status in the field clearly calls for innovative measurements involving manifold correlations and new observables. The outcome of the attempt done in this work in this direction, based on the coincident measurement of prompt -rays is reported, and encouraging perspectives are discussed.