Does Compound Nucleus remember its Isospin- An Evidence from the Fission Widths

Abstract

We present an evidence of isospin effects in nuclear fission by comparing the fission widths for reactions involving different isospin states of the same compound nucleus (CN). Yadrovsky suggested this possibility in 1975. Yadrovsky obtained the fission widths for two reaction data sets, namely $^{206}$Pb($\alpha$,f) and $^{209}$Bi(p,f), both leading to same CN, and concluded that "a nucleus remembers the isospin value of the nuclear states leading to fission". We obtain the fission decay widths for both the $T_0+1/2$ and $T_0-1/2$ states of CN by using two appropriate reaction data sets. We then compare the fission widths for the two isospin states of CN. More specifically, we have chosen the combination of $^{206}$Pb($\alpha$,f) and $^{209}$Bi(p,f) same as presented in Yadrovsky's paper and $^{235}$U(d,f) and $^{236}$U(p,f) reaction data sets in this study. A significant difference between the ratios of fission decay widths to total decay widths for different isospin values suggests that isospin plays an important role in fission.