N.K. Ganguly

One- and two-body dissipation in heavy-ion collisions

Abstract A microscopic theory has been formulated for one- and two-body dissipation in collisions between two heavy nuclei. With a nucleon-nucleon interaction as the basic perturbation in a density matrix approach with “linear response” approximations, the one- and two-body nuclear friction coefficients for the 40 Ca + 40 Ca system have been calculated and their dependence on relative kinetic energy and smearing of nuclear single-particle states was obtained. The results of our calculation show that: (a) the combined one- and two-body friction coefficients compare favourably with phenomenological values, (b) the one-body dissipation is more effective than two-body in kinetic energy damping, while both the mechanisms are comparable for the damping of relative angular momentum, (c) the importance of the two-body friction compared to one-body increases at higher relative kinetic energies and (d) the effect of introducing a smearing in nuclear levels appears as a lowering of nuclear friction.

Isobaric analogue resonances in the 80Se(p, n)80Br reaction

The toral (p, n) reaction cross section for 80 Se has been measured as a function of proton energy in the energy range from ≈ 2.7 to 5.375 MeV with fine resolution (≈ 5 keV). Several prominent isobaric analogue resonances have been measured. A detailed shape analysis of the isobaric analogue resonances has been performed to determine the proton width Γ p , the spreading width W and the spectroscopic factor S for the various resonances.

Consistent microscopic and macroscopic analyses of the composite particle optical potential

Abstract The optical model potential has been obtained for mass-3 projectiles (3H and 3He) for a range of target nuclei using three different approaches. The potentials along with the cross-section fits are presented. A microscopic calculation of the composite particle optical potential has been performed by folding a realistic nucleon-triton (or helion) interaction into the density distribution of the targets. Optical potentials for 3H and 3He have also been studied starting from nucleon-nucleus optical potentials known a priori. The second-order potentials extracted from these two methods have been compared. The equivalent sharp radii of the real potentials of first set of calculations were consistently lower than the second set. This indicates the need for a saturating term in the nucleon-triton interaction. In the present work, saturation has been introduced through a density-dependent multiplicative factor to the n-t interaction. A phenomenological analysis also has been carried out for t-elastic scattering at 20 MeV off a wide range of targets with the real well depth V0 lying around 125 MeV, which is considered to be the most physical range for V0.

Nucleus‐nucleus potential from alpha‐alpha interaction

A method is presented by which the potential between a pair of even‐N=even‐Z nuclei can be calculated by describing the nuclei in terms of alpha clusters and using a free alpha‐alpha interaction. The results for 16O+16O and 16O+40Ca are presented and compared with other results.

Form factor of one-body nuclear friction

Abstract It is suggested from a microscopic calculation that the one-body nuclear friction form factor should be systematically different from that determined from the gradient of the nucleus-nucleus potential as has been assumed hitherto.

SCATTERING OF MASS-3 PROJECTILES FROM HEAVY NUCLEI

Publisher Summary This chapter describes the scattering of mass-3 projectiles from heavy nuclei. It is well known that α-particle scattering shows most of the features observed in heavy ion scattering. It is found that the molecular type potentials with a soft repulsive core and a shallow attractive well used for heavy ion collisions can be used to fit the elastic scattering data of mass-3 projectiles also. The chapter discusses the way by which the potential is generated, with focus on saturation and second order effect through a density dependent interaction between nucleon and mass-3 projectiles. The asymmetry dependence observed in the potential describing the scattering of mass-3 particles from heavier nuclei actually originates from the isospin interaction, when triton and helion are treated as two members of an isospin doublet. The analysis proves that similar to nucleons, the asymmetry dependence observed for mass-3 potentials can indeed be explained as a consequence of a complex isospin interaction, treating triton and helion to form an isospin doublet.