Study of pairing deformations by means of two-particle transfer reactions

Abstract

The macroscopic approach for two-particle transfer reactions is applied in normal spherical nuclei and pairing deformation parameters /?p are estimated. For Ni isotopes the macroscopic approach works reasonably well while for the lead region strong energy dependence of the/~p values has been observed. It is shown that alpha-transfer reactions can also be treated within this formalism as couplings of the two-neutron and two-proton channels.

Pairing correlations of nucleons and multi-nucleon transfer between heavy nuclei

“…(ii) The role of the pairing interaction in states with low binding energy, e.g. in very neutronrich isotopes, is of great interest, because information on the pairing interaction at low densities could be obtained [54]. In particular the effect of the continuum and the role of coupling to collective low-lying vibrations of the core in weakly bound systems has to be further clarified [27].…”

“…In all cases, the shape of the angular distribution is well reproduced at all energies considered (cf [41]). The energy dependence of the process has been specifically studied in [54], where the two spherical regions around the nickel and lead isotopes have been considered. The systematic decreasing behaviour of β p with bombarding energy is a clear indication of the complicated origin of the effective form factor, in particular emphasizing the dynamical aspects arising from higher-order processes.…”

Pair density fluctuations in a number projected BCS approximation

“…So far the calculations which have been reported in the just mentioned works Permanent address." Department of Physics, University of La Plata, AR-1900 La Plata, Argentina -" Fellow of the CONICET, Argentina [4,5,7] and in other related works [6,8] have been performed by using separable pairing interactions of the monopole type and in the framework of the BCS approximation [1][2][3]. It would then be worth to study the extent in which these approximations remain valid when a number conserving version of the BCS formalism is used, instead of the conventional non-number conserving one.…”

“…The study of pair density fluctuations and of pair transition densities in superfluid nuclei [1][2][3] has been the subject of recent publications [4][5][6][7][8]. Although the basic formulation of a microscopic model for the description of pair density fluctuations is a matter of textbooks [1][2][3], the interest in the problem has been renewed by the work of Dasso and Pollarolo [4] which have made a case for the use of macroscopic form factors for nucleon pair transfer processes.…”