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

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 target 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 elastic and inelastic breakup (or stripping) neutron-removal cross sections. We apply the methods to model the single-neutron removal reactions induced by ${}^{11}\mathrm{Be}$ and ${}^{17}\mathrm{C}$ secondary fragmentation beams incident on a ${}^9\mathrm{Be}$ target. Our calculations indicate that dynamical deformation effects on the elastic breakup component of the knockout cross section can be significant. This is the largest effect. The more geometrical stripping cross section is found to be hardly changed by the inclusion of the deformed core degree of freedom.

Figure 1

Schematic of the deformed-core plus neutron projectile system incident on a spherical target indicating the angular momentum quantum numbers, the core orientation $\stackrel{\wedge }{\Omega }$, and the center of mass impact parameter b.

Figure 2

Dependence of the calculated stripping and diffractive single-neutron removal cross sections, and their sum, upon the assumed core deformation ${\beta }_2$ for the ${}^9\mathrm{Be}$(${}^{17}\mathrm{C}$,${}^{16}\mathrm{C}$)X reaction at 62 MeV per nucleon. The calculations are for a spectroscopic factor of 1.