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

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${}_{\text{lab}}$ $\approx$ 65-85 MeV using offline $\gamma$-spectroscopy. To gain insights into the formation and decay modes of these residues, experimentally measured cross-sections have been analyzed using the statistical model codes PACE4 and EMPIRE. In the analysis, the cross-sections of p$x$n (${}^{127,126,125}$Cs), $\alpha$xn (${}^{125}$Xe), and $\alpha$p$x$n (${}^{123}$I) channels are substantially fed from their higher charge isobars via ${\beta }^{+}$ decay and electron capture. The contribution of ${\beta }^{+}$ decay and electron capture has been calculated using the prescription of Cavinato $et$ $al.$\cite{cavinato1995study} and the independent cross-sections of these residues have been compared with PACE4 and EMPIRE calculations, which fairly reproduce the independent cross-sections of evaporation-residue within the experimental uncertainties. Interestingly, it has been observed that the $\alpha$-emitting channels, contrary to established findings in reactions involving $\alpha$ cluster projectiles (e.g., ${}^{12}$C, ${}^{16}$O, etc.) at the studied energy range, display negligible or no contribution of incomplete fusion (ICF) in ${}^{12}$C+${}^{118}$Sn system. The absence of ICF has been verified through a complementary experiment in which the forward recoil ranges of ${}^{126}$Ba(4n) and ${}^{125}$Xe($\alpha$n) channels have been measured. Present measurements reveal anomalous suppression of ICF in the ${}^{12}$C+${}^{118}$Sn system, providing new constraints on entrance-channel mass-asymmetry systematics absent in prior data.