Effect of the repulsive core in the proton-neutron potential on deuteron elastic breakup cross sections

TL;DR

This study investigates how the short-range repulsive core of the proton-neutron potential influences deuteron elastic breakup cross sections, finding it has negligible effect at energies from 40 MeV to 1 GeV due to the peripherality of the process.

Contribution

It demonstrates that the repulsive core does not affect breakup cross sections because the process is peripheral except for s-wave breakup, providing new insights into the reaction mechanism.

Findings

Repulsive core does not affect cross sections at studied energies.

Breakup processes with non-zero angular momentum are peripheral.

S-wave breakup involves the entire deuteron spatial region.

Abstract

The role of the short-range part (repulsive core) of the proton-neutron ($pn$) potential in deuteron elastic breakup processes is investigated. A simplified one-range Gaussian potential and the Argonne V4' (AV4') central potential are adopted in the continuum-discretized coupled-channels (CDCC) method. The deuteron breakup cross sections calculated with these two potentials are compared. The repulsive core is found not to affect the deuteron breakup cross sections at energies from 40 MeV to 1 GeV. To understand this result, an analysis of the peripherality of the elastic breakup processes concerning the $p$-$n$ relative coordinate is performed. It is found that for the breakup processes populating the $pn$ continua with orbital angular momentum $\ell$ different from 0, the reaction process is peripheral, whereas it is not for the breakup to the $\ell=0$ continua (the s-wave breakup). The result of the peripherality analysis indicates that the whole spatial region of deuteron contributes to the s-wave breakup.