Linear Polarization Measurements for High-Spin States in 146Gd

TL;DR

This study used gamma-ray linear polarization measurements to determine the spin and parity of high-spin states in 146Gd, providing new insights into its nuclear structure and the role of neutron-core breaking at high energies.

Contribution

It presents the first direct polarization-based parity assignments for 146Gd high-spin states and interprets these findings with shell model calculations including neutron-core breaking effects.

Findings

Unambiguous spin and parity assignments for most levels.

Shell model explains low-lying states up to Jπ=19+ and 9-.

Neutron-core breaking is crucial for states above 7 MeV.

Abstract

A {\gamma}-ray linear polarization measurement has been performed to directly determine the parities for the levels in 146Gd nucleus. High-spin states in this nucleus were populated in a reaction 115In + 34S at 140 MeV incident energy. Linearly polarized {\gamma} - rays emitted from oriented states were measured using a Compton polarimeter consisting of an array of 8 Compton-suppressed Clover detectors. Unambiguous assignments of the spin and parity have been made for most of the observed levels and changes made in the previously reported spin-parity assignments for a few levels. Shell model calculations performed with judicious truncation over the {\pi}(gdsh) valence space interpret the structure of only the low-lying levels up to J{\pi} = 19+ and 9-. N = 82 neutron-core breaking is found to be essential for high spin states with excitation energies Ex > 7 MeV.