Dynamical core deformation effects on single-nucleon knockout reactions at fragmentation beam energies

Abstract

The effects of core deformation and of its dynamical reorientation and rotational excitation on the inclusive single-neutron knockout reaction cross sections on light spherical nuclei are examined. The projectile nuclei are modeled within the framework of a weak-coupling, quadrupole-deformed core-plus-neutron two-body model. We formulate the inclusion of this non-spectator-core degree of freedom within the nonperturbative eikonal model and calculate the diffractive break up and stripping neutron-removal cross sections. We apply the methods to model the single-neutron removal reactions induced by 11Be and 17C and secondary fragmentation beams incident on a 9Be target. Our calculations indicate that dynamical deformation effects on the diffractive break up component of the knockout cross section can be significant. For the two reactions studied here, the diffractive break up cross section is significantly enhanced. This effect is found to be very surface localised, thus the importance of core deformation is increased the more tightly bound the projectile system. The quadrupole deformation parameter and excitation energy of the core also influence the magnitude of this enhancement of the diffractive cross section, which is relatively insensitive to the projectile energy. The stripping cross section is found to be virtually unchanged by the inclusion of the deformed core degree of freedom.