Transfer/Breakup Channel Couplings in Sub-barrier Fusion Reactions

TL;DR

This paper investigates the influence of inelastic, transfer, and breakup channel couplings on sub-barrier fusion reactions using coupled-channel calculations, highlighting the importance of neutron transfer and breakup effects in fusion cross sections.

Contribution

It introduces comprehensive coupled-channel calculations including neutron transfer and breakup couplings, demonstrating their impact on fusion cross sections near the Coulomb barrier.

Findings

Neutron transfer effects enhance sub-barrier fusion cross sections.

Breakup couplings are crucial for accurately modeling fusion with weakly bound projectiles.

Coupled-channel calculations successfully reproduce experimental fusion enhancements.

Abstract

With the recent availability of state-of-the-art radioactive ion beams, there has been a renew interest in the investigation of nuclear reactions with heavy ions near the Coulomb barrier. The role of inelastic and transfer channel couplings in fusion reactions induced by stable heavy ions can be revisited. Detailed Analysis of recent experimental fusion cross sections by using standard coupled-channel calculations is first discussed. Multi-neutron transfer effects are introduced in the fusion process below the Coulomb barrier by analyzing 32S+90,96Zr as benchmark reactions. The enhancement of fusion cross sections for 32S+96Zr is well reproduced at sub-barrier energies by NTFus code calculations including the coupling of the neutron-transfer channels following the Zagrebaev semi-classical model. Similar effects for 40Ca+90Zr and 40Ca+96Zr fusion excitation functions are found. The breakup coupling in both the elastic scattering and in the fusion process induced by weakly bound stable projectiles is also shown to be crucial. In the second part of this work, full coupled-channel calculations of the fusion excitation functions are performed by using the breakup coupling for the more neutron-rich reaction and for the more weakly bound projectiles. we clearly demonstrate that Continuum-Discretized Coupled-Channel calculations are capable to reproduce the fusion enhancement from the breakup coupling in 6Li+59Co.