Exploring $\beta^+$ decay/EC residues in $^{118}$Sn($^{12}$C,x)$^{130}$Ba reaction

TL;DR

This study measures fusion cross-sections of various residues in the $^{12}$C + $^{118}$Sn reaction at 65-85 MeV and analyzes the formation and decay modes using theoretical models, revealing insights into decay channels and fusion mechanisms.

Contribution

It provides experimental data and theoretical analysis of residue formation in $^{12}$C + $^{118}$Sn reactions, highlighting the role of $eta^+$ decay, electron capture, and the negligible contribution of incomplete fusion.

Findings

Cross-sections of residues are well reproduced by PACE4 and EMPIRE models.

$eta^+$ decay and electron capture significantly contribute to residue populations.

Incomplete fusion is negligible in $ ext{α}$-emitting channels at these energies.

Abstract

The fusion cross-sections of $^{126}$Ba, $^{127,126,125}$Cs, $^{125,123,122}$Xe and $^{124,123}$I residues, populated via $x$n, p$x$n, $\alpha$$x$n, and $\alpha$p$x$n channels, have been measured in $^{12}$C+$^{118}$Sn system at E$_{\textrm{lab}}$ $\approx$ 65-85 MeV. For an insight into the formation and decay modes of these residues, experimentally measured cross-sections have been analyzed in the framework of theoretical model codes PACE4 and EMPIRE. The cross-sections of p$x$n ($^{127,126,125}$Cs), $\alpha$xn ($^{125}$Xe), and $\alpha$p$x$n ($^{123}$I) channels have been found to be substantially fed from their higher charge isobars via $\beta^+$ decay and electron capture. In order to deduce the contribution of higher charge isobars in the population of these residues, the independent cross-sections of evaporation residues have been calculated using the prescription of Cavinato $et$ $al.$ and compared with that calculated using theoretical model codes. It has been found that the PACE4 and EMPIRE calculations fairly reproduce the independent cross-sections of evaporation residues within the experimental uncertainties. Interestingly, it has been found that the $\alpha$-emitting channels, contrary to established findings in reactions involving $\alpha$ cluster projectiles (e.g., $^{12}$C, $^{16}$O, etc.) at low incident energies, display negligible contribution of incomplete fusion (ICF). A comparison of incomplete fusion fraction as a function of entrance channel mass-asymmetry for reactions involving $^{12}$C projectile with nearby targets indicates dissimilar behavior of $^{118}$Sn target.