Breakup dynamics of a neutron-halo projectile on heavy target at deep sub-barrier energies

TL;DR

This study investigates the breakup and fusion behaviors of neutron-halo $^{11}$Be projectiles on lead targets at deep sub-barrier energies, revealing that breakup remains dominant due to Coulomb continuum couplings, similar to proton-halo cases.

Contribution

It demonstrates that Coulomb continuum-continuum couplings significantly enhance breakup cross-sections at sub-barrier energies for neutron-halo projectiles, extending previous proton-halo findings.

Findings

Breakup channel dominates at sub-barrier energies.

Coulomb continuum-continuum couplings enhance breakup cross-sections.

Breakup may be delayed by continuum couplings, affecting reaction dynamics.

Abstract

By studying the total fusion and breakup cross-sections in the interaction of the neutron-halo $^{11}{\rm Be}$ projectile on the lead target $^{208}$Pb, it is shown that, even for the neutron-halo projectile, the breakup channel remains the most dominant reaction channel at sub-barrier energies, following a characteristic behavior that was also previously verified for the case of the proton-halo projectile $^8{\rm B}$. This feature is found to emanate from the enhancement of the breakup cross-section, due to the continuum-continuum couplings coming exclusively from its Coulomb component. We further speculate that the enhancement of the Coulomb breakup cross-section at sub-barrier incident energies by the continuum-continuum couplings could be associated with the projectile breaking up on the outgoing trajectory, provided these couplings can be proven to delay the breakup process.