Near-barrier fusion ofS32+Zr90,96: The effect of multi-neutron

Abstract

Fusion excitation functions have been measured for the first time with rather good accuracy for 32 S + 90 Zr and 32 S + 96 Zr near and below the Coulomb barrier. The sub-barrier cross sections for 32 S + 96 Zr are much larger than for 32 S + 90 Zr. A coupled-channels calculation considering the inelastic excitations is capable of describing sub-barrier enhancement only for 32 S + 90 Zr. The unexplained part for 32 S + 96 Zr is found to be correlated with the positive-Q-value intermediate neutron transfers in this system. The comparison with 40 Ca + 96 Zr suggests that couplings to the positive-Q-value neutron transfer channels may play a role in the sub-barrier fusion enhancement. Multi-neutron transfers are taken into account in Zagrebaev's semiclassical model to explain the discrepancies of the sub-barrier fusion cross sections for 32 S + 96 Zr.

Examining the role of transfer coupling in sub-barrier fusion ofTi46,50+Sn124

“…Besides 40 Ca induced reactions, a very large sub-barrier fusion enhancement has been reported for 32 S induced reactions [35,36]. As an example, the sub-barrier fusion enhancement in 32 [37,38].…”

Breakup and n -transfer effects on the fusion reactions Li6,7+Sn120,Fisichella1, Shotter2, Фігуера3 et al. 2017Phys. Rev. C19030View full textAdd to dashboardCite

“…For example, enhanced fusion cross sections have been observed for 28 Si + 94 Zr [10], 32 S + 96 Zr, 110 Pd [11,12] and 40 Ca + 48 Ca, 96 Zr, 124,132 Sn [13][14][15][16] systems compared to their isotopic counterparts characterized by lower Q values for neutron transfer. However, the fusion excitation functions for systems like Sn+Ni, Te+Ni [17], O+Ge [18], and Ni+Mo [19] do not show significant differences, when different isotopes of the colliding nuclei are considered, even though the systems present very different Q values for multineutron transfer channels.…”

“…1. However it is anticipated that a future experimental program will be undertaken with beams of unstable lithium isotopes 8 Li, 9 Li, 11 Li. Since such beams will be of significantly lower intensity than for stable Li beams, it will be essential to use a stack of target/catcher foils.…”

“…However, the fusion excitation functions for systems like Sn+Ni, Te+Ni [17], O+Ge [18], and Ni+Mo [19] do not show significant differences, when different isotopes of the colliding nuclei are considered, even though the systems present very different Q values for multineutron transfer channels. In addition, a recent study concerning the fusion reaction 32 S + 94 Zr [20] has shown a sub-barrier enhancement with respect to the 32 S + 96 Zr reaction, [11] although the neutron transfer Q value for 32 S + 94 Zr is smaller.…”

Nuclear reactions studied by quasi-elastic measurements with high precision at backward angles

“…The barrier distributions extracted from these fusion data and the CC calculations including the neutron transfer channels were presented in Ref. [25] and [34]. Recently, there has been considerable interest in the breakup effects on the fusion and scattering reactions.…”