First measurement of several $\beta$-delayed neutron emitting isotopes beyond N=126

TL;DR

This paper reports the first measurements of $eta$-delayed neutron emission probabilities and half-lives for very heavy, neutron-rich isotopes beyond N=126, providing critical data for nuclear models and r-process nucleosynthesis.

Contribution

It presents the first experimental data on $eta$-delayed neutron emission for isotopes beyond N=126, testing and constraining nuclear models in this extreme region.

Findings

Neutron emission observed in the heaviest isotopes to date.

Measured $eta$-decay half-lives for 20 isotopes.

Provides data to improve nuclear models for r-process.

Abstract

The $\beta$-delayed neutron emission probabilities of neutron rich Hg and Tl nuclei have been measured together with $\beta$-decay half-lives for 20 isotopes of Au, Hg, Tl, Pb and Bi in the mass region N$\gtrsim$126. These are the heaviest species where neutron emission has been observed so far. These measurements provide key information to evaluate the performance of nuclear microscopic and phenomenological models in reproducing the high-energy part of the $\beta$-decay strength distribution. In doing so, it provides important constraints to global theoretical models currently used in $r$-process nucleosynthesis.