Anomalous Fluctuations of $s$-Wave Reduced Neutron Widths of ${}^{192,194}\mathrm{Pt}$ Resonances

We obtained an unprecedentedly large number of $s$-wave neutron widths through $\mathcal{R}$-matrix analysis of neutron cross-section measurements on enriched Pt samples. Careful analysis of these data rejects the validity of the Porter-Thomas distribution with a statistical significance of at least 99.997%.

Figure 1

Energy-reduced values of observables $g_J{\Gamma }_{\lambda n}$ for individual resonances of ${}^{194}\mathrm{Pt}$. Values represented by full-circle points belong to resonances to which we assigned ${\ell }_n=0$. For the meaning of thresholds $T_0$, $T_{01}$, and $T$, see the text.

Figure 2

Plot of $z(\nu ,\mathcal{E}[{\Gamma }_{\lambda n}^0])$ constructed from the ${}^{194}\mathrm{Pt}$ data.

Figure 3

Values of probabilities $P(\widehat{\nu }>{\widehat{\nu }}_{\mathrm{expt}})$, $P(Z>Z_{\mathrm{expt}})$ and $P(Z^2<Z_{\mathrm{expt}}^2)$ as functions of $\mathcal{E}[{\Gamma }_{\lambda n}^0]$ deduced from data on neutron resonances of ${}^{192,194}\mathrm{Pt}$. Values referring to statistics $\nu$, $Z^2$, and $Z$ are plotted by symbols ●, ▿, and ▵, respectively.