Fusion Hindrance and Pauli Blocking in $^{58}$Ni + $^{64}$Ni
In: ISSN: 1742-6596 ; EISSN: 1742-6588, 2019
Online
Konferenz
Zugriff:
International audience ; 58 Ni + 64 Ni is the first case where the influence of positive Q-value transfer channels on sub-barrier fusion was evidenced, in a very well known experiment by Beckerman et al., by comparing with the two systems 58 Ni + 58 Ni and 64 Ni + 64 Ni. Subsequent measurements on 64 Ni + 64 Ni showed that fusion hindrance is clearly present in this case. On the other hand, no indication of hindrance can be observed for 58 Ni + 64 Ni down to the measured level of 0.1 mb. In the present experiment the excitation function has been extended by two orders of magnitude downward. The cross sections for 58 Ni + 64 Ni continue decreasing very smoothly below the barrier, down to 1 µb. The logarithmic slope of the excitation function increases slowly, showing a tendency to saturate at the lowest energies. No maximum of the astrophysical Sfactor is observed. Coupled-channels (CC) calculations using a Woods-Saxon potential and including inelastic excitations only, underestimate the sub-barrier cross sections by a large amount. Good agreement is found by adding two-neutron transfer couplings to a schematical level. This behaviour is quite different from what already observed for 64 Ni+ 64 Ni (no positive Q-value transfer channels available), where a clear low-energy maximum of the S-factor appears, and whose excitation function is overestimated by a standard Woods-Saxon CC calculation. No hindrance effect is observed in 58 Ni+ 64 Ni in the measured energy range. This trend at deep subbarrier energies reinforces the recent suggestion that the availability of several states following transfer with Q >0, effectively counterbalances the Pauli repulsion that, in general, is predicted to reduce tunneling probability inside the Coulomb barrier.
Titel: |
Fusion Hindrance and Pauli Blocking in $^{58}$Ni + $^{64}$Ni
|
---|---|
Autor/in / Beteiligte Person: | Stefanini, Alberto M. ; Montagnoli, Giovanna ; Fabbro, Mirco Del ; Colucci, Giulia ; Colovic, Petra ; Corradi, Lorenzo ; Fioretto, Enrico ; Galtarossa, Franco ; Goasduff, Alain ; Grebosz, Jerzy ; Heine, Marcel ; Jaworski, Grzegorz ; Mazzocco, Marco ; Mijatovic, Tea ; Szilner, Suzana ; Bajzek, Martin ; Brugnara, Daniele ; Siciliano, Marco ; Zanon, Irene ; Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU) ; Université Paris-Saclay-Direction de Recherche Fondamentale (CEA) (DRF (CEA)) ; Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA) ; Institut Pluridisciplinaire Hubert Curien (IPHC) ; Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS) ; Istituto Nazionale di Fisica Nucleare, Sezione di Padova (INFN, Sezione di Padova) ; Istituto Nazionale di Fisica Nucleare (INFN) ; Commissariat à l'énergie atomique et aux énergies alternatives (CEA) |
Link: | |
Zeitschrift: | ISSN: 1742-6596 ; EISSN: 1742-6588, 2019 |
Veröffentlichung: | HAL CCSD ; IOP Science, 2019 |
Medientyp: | Konferenz |
DOI: | 10.1088/1742-6596/1643/1/012105 |
Schlagwort: |
|
Sonstiges: |
|