Uncertainties in the analysis of neutron resonance data

TL;DR

This paper examines the impact of cutoff errors in analyzing neutron resonance data and confirms that the Nuclear Data Ensemble significantly disagrees with random-matrix theory predictions.

Contribution

It identifies and quantifies the systematic cutoff error in neutron resonance data analysis and reanalyzes the NDE considering this error, reaffirming the disagreement with RMT.

Findings

Cutoff error increases with higher cutoff and fewer data points.

Reanalysis confirms NDE's significant deviation from RMT predictions.

Systematic errors affect the interpretation of neutron resonance data.

Abstract

Recent analyses of the distribution of reduced neutron widths in the Nuclear Data Ensemble (NDE) and in the Pt isotopes find strong disagreement with predictions of random-matrix theory. These analyses combine the maximum-likelihood method with a cutoff on the reduced neutron widths. We show that the method introduces a systematic error (the "cutoff error"). That error (seemingly taken into account for the Pt data) increases with increasing cutoff and decreasing number of data points. We reanalyse the NDE taking the cutoff error into account. While differing in detail, our results confirm the earlier conclusion that the NDE disagrees significantly from RMT predictions.