Coulomb breakup of $^6\rm{Li}$ into $\alpha\,+\,\rm{d}$ in the field of ion $^{208}\rm{Pb}$

TL;DR

This paper calculates the Coulomb breakup cross section of lithium-6 into alpha and deuteron in the field of lead-208, analyzing the reaction mechanism and comparing with experimental data to understand the dominance of Coulomb dissociation.

Contribution

It applies a semiclassical method with fitted Woods-Saxon potential parameters to model the breakup and validates the two-particle approach through radiative capture analysis.

Findings

Large forward-backward asymmetry observed in particle emission.

Coulomb dissociation dominates at energies above 300 keV.

Nuclear distortion effects are significant near zero energy but smaller than previous reports.

Abstract

The triple differential cross section of $^{208}\rm{Pb}(^6\rm{Li};\alpha,\rm{d})^{208}\rm{Pb}$ elastic Coulomb breakup is calculated using the semiclassical method. We fit the parameters of the Woods-Saxon potential using the experimental $\alpha-\rm{d}$ phase shifts for different states to describe the relative motion of $\alpha$-particle and deuteron. In order to check the validity of the two particle approach for $\alpha-d$ system we apply a potential model to describe the $^2\rm{H}(\alpha,\gamma)^6\rm{Li}$ radiative capture. Our results for the Coulomb breakup of $^6\rm{Li}$ show large value of the forward-backward asymmetry of the $\alpha$-particle and deuteron emission around zero energy in the $^6\rm{Li}$ center-of-mass (c.m.) system. Comparison of the results of our calculation with experimental data gives evidence for the dominance of the Coulomb dissociation mechanism at the $\alpha-d$ relative energy larger than $E_{\alpha\,d}>300\,\rm{keV}$ and sufficiently big contribution of nuclear distortion at $E_{\alpha\,d}$ near zero energy, but essentially smaller than the value reported in Ref.[F. Hammache et al. Phys.Rev. C82, 065802 (2010)].