Accueil du site > Publications récentes > Microscopic description of pair transfer between two superfluid Fermi systems : Combining phase-space averaging and combinatorial techniques
David Regnier, Denis Lacroix, Guillaume Scamps, and Yukio Hashimoto
In a mean-field description of superfluidity, particle number and
gauge angle are treated as quasiclassical conjugated variables.
This level of description was recently used to describe nuclear
reactions around the Coulomb barrier. Important effects of the
relative gauge angle between two identical superfluid nuclei
(symmetric collisions) on transfer probabilities and fusion
barrier have been uncovered. A theory making contact with
experiments should at least average over different initial
relative gauge-angles. In the present work, we propose a new
approach to obtain the multiple pair transfer probabilities
between superfluid systems. This method, called phase-space
combinatorial (PSC) technique, relies both on phase-space
averaging and combinatorial arguments to infer the full pair
transfer probability distribution at the cost of multiple
mean-field calculations only. After benchmarking this approach in
a schematic model, we apply it to the collision 20O+20O
at various energies below the Coulomb barrier. The predictions for
one pair transfer are similar to results obtained with an
approximated projection method, whereas significant differences
are found for two pairs transfer. Finally, we investigated the
applicability of the PSC method to the contact between
nonidentical superfluid systems. A generalization of the method is
proposed and applied to the schematic model showing that the pair
transfer probabilities are reasonably reproduced. The
applicability of the PSC method to asymmetric nuclear collisions
is investigated for the 14O+20O
collision and it turns out that unrealistically small single- and
multiple pair transfer probabilities are obtained. This is
explained by the fact that relative gauge angle play in this case
a minor role in the particle transfer process compared to other
mechanisms, such as equilibration of the charge/mass ratio. We
conclude that the best ground for probing gauge-angle effects in
nuclear reaction and/or for applying the proposed PSC approach on
pair transfer is the collisions of identical open-shell spherical
nuclei.
Voir en ligne : Phys. Rev. C 97, 034627
Institut de Physique Nucléaire Orsay - 15 rue Georges CLEMENCEAU - 91406 ORSAY (FRANCE) |
||
Ce site est optimisé pour les navigateurs suivants Firefox, Chrome, Internet explore 9 |