19 research outputs found
Coupled-Channel Effects in Collisions between Heavy Ions near the Coulomb Barrier
With the recent availability of state-of-the-art heavy-ion stable and
radioactive beams, there has been a renew interest in the investigation of
nuclear reactions with heavy ions. I first present the role of inelastic and
transfer channel couplings in fusion reactions induced by stable heavy ions.
Analysis of experimental fusion cross sections by using standard
coupled-channel calculations is discussed. The role of multi-neutron transfer
is investigated in the fusion process below the Coulomb barrier by analyzing
S+Zr as benchmark reactions. The enhancement of fusion cross
sections for S+Zr is well reproduced at sub-barrier energies by
NTFus code calculations including the coupling of the neutron-transfer channels
following the Zagrebaev semi-classical model. Similar effects for
Ca+Zr and Ca+Zr fusion excitation functions are
found. The breakup coupling in both the elastic scattering and in the fusion
process induced by weakly bound stable projectiles is also shown to be crucial.
In this lecture, full coupled-channel calculations of the fusion excitation
functions are performed by using the breakup coupling for the more neutron-rich
reaction and for the more weakly bound projectiles. I clearly demonstrate that
Continuum-Discretized Coupled-Channel calculations are capable to reproduce the
fusion enhancement from the breakup coupling in Li+Co.Comment: 14 pages. 6 figure
From the stable to the exotic: clustering in light nuclei
A great deal of research work has been undertaken in alpha-clustering study
since the pioneering discovery of 12C+12C molecular resonances half a century
ago. Our knowledge on physics of nuclear molecules has increased considerably
and nuclear clustering remains one of the most fruitful domains of nuclear
physics, facing some of the greatest challenges and opportunities in the years
ahead. The occurrence of "exotic" shapes in light N=Z alpha-like nuclei is
investigated. Various approaches of the superdeformed and hyperdeformed bands
associated with quasimolecular resonant structures are presented. Evolution of
clustering from stability to the drip-lines is examined: clustering aspects
are, in particular, discussed for light exotic nuclei with large neutron excess
such as neutron-rich Oxygen isotopes with their complete spectroscopy.Comment: 15 pages, 5 figures, Presented at the International Symposium on "New
Horizons in Fundamental Physics - From Neutrons Nuclei via Superheavy
Elements and Supercritical Fields to Neutron Stars and Cosmic Rays" held at
Makutsi Safari Farm, South Africa, December 23-29, 2015. arXiv admin note:
substantial text overlap with arXiv:1402.6590, arXiv:1303.0960,
arXiv:1408.0684, arXiv:1011.342
Production and study of heavy neutron rich nuclei formed in multi-nucleon transfer reactions
A new setup is proposed to produce and investigate heavy neutron-rich nuclei located along the neutron closed shell N = 126. This "blank spot" of the nuclear map can be reached neither in fusion-fission reactions nor in fragmentation processes widely used nowadays for the production of exotic nuclei. The present limits of the upper part of the nuclear map are very close to stability while the unexplored area of heavy neutron-rich nuclides along the neutron closed shell N = 126 is extremely important for nuclear astrophysics investigations and, in particular, for the understanding of the r-process of astrophysical nucleosynthesis. A new way was recently proposed for the production of these nuclei via low-energy multi-nucleon transfer reactions. The estimated yields of neutron-rich nuclei are found to be rather high in such reactions and several tens of new nuclides can be produced, for example, in the near-barrier collision of 136Xe with 208Pb. This setup could definitely open a new opportunity in the studies at heavy-ion facilities and will have significant impact on future experiments. © 2013 Springer Science+Business Media Dordrecht.status: publishe