Deformation, orientation, and medium effects in16,19C+Creactions

Abstract

The shape, deformation, and orientation dependence as well as in-medium effects are investigated for the reaction cross sections of 16,19 C + C systems within the optical Glauber theory, which is currently used to deduce information about the structure of exotic nuclei. A density-and energy-dependent effective nucleon-nucleon reaction cross section is used locally to study in-medium effects. The projectile deformation is treated by a deformed Fermi shape with quadrupole and hexadecapole deformations, where the deformation parameters of 16 C and 19 C are calculated from the Lagrangian density of the relativistic mean-field (RMF) model. A strong prolate deformation is predicted for 16 C while a more stronger oblate shape is predicted for 19 C. Medium effects are found to be important for extracting reliable information about the nuclear densities and radii. The deformations and orientations strongly affected the reaction cross section. The difference in the reaction cross section calculated at orientation angle π/2 and at zero degree is of the order of 400 mb. The integrated reaction cross section over all orientation angles (angle average), including in-medium effects, predicted the experimental reaction cross section of 19 C + 12 C. For 16 C + 12 C the rms radius of 16 C is increased to about 7% than that predicted by the RMF model in order to predict the experimental data. This greater increase in the rms radius of 16 C, to about 3 fm, indicates a neutron halo structure for this nucleus. The deduced spherical Fermi distributions which fit the experimental data of 16,19 C + 12 C systems are in fact a prediction of the angle average cross sections.

Nuclear matter distributions in the neutron-rich carbon isotopes $^{14-17}$C from intermediate-energy proton elastic scattering in inverse kinematics

“…The same conclusion about the halo formation in 16 C was also drawn in Ref. [26], where a strong prolate deformation of this nucleus was predicted. However, the 16 C nucleus has a relatively large neutron separation energy, S 2n = 5.468 MeV [15], which is not consistent with the existence of a halo in this nucleus.…”

“…For the core radius and the radius of the valence neutrons distribution, the following mean values were determined: R c = 2.41(5) fm and R v = 4.20 (26) fm.…”

Influence of deformed potentials on elastic scattering reactions involving deformed projectile-spherical target

“…If one or both of nuclei are deformed, the effect of deformation and orientation of nuclei should be included in the analysis of nuclear interactions. In this context, the deformation effect on nuclear reactions was investigated with different studies [7][8][9]. It is known that the theoretical calculations with deformed case are more difficult.…”