Structure of $^{240}$Pu: Evidence for Octupole Phonon Condensation?

TL;DR

This study investigates the level structure of $^{240}$Pu, providing evidence for strong octupole correlations and supporting the concept of octupole phonon condensation through detailed nuclear transition observations.

Contribution

It presents new experimental data on $^{240}$Pu's level structure, highlighting features consistent with octupole phonon condensation, a novel interpretation in nuclear structure physics.

Findings

Presence of both $I^{+}{ o}(I-1)^{-}$ and $I^{-}{ o}(I-1)^{+}$ E1 transitions

Observation of an additional even-spin, positive-parity band

Delayed alignment in the yrast band

Abstract

The expanded level structure of $^{240}$Pu available from the present study highlights the role of strong octupole correlations in this nucleus. Besides a delayed alignment in the yrast band, the observations include the presence of both $I^{+}{\to}(I-1)^{-}$ and $I^{-}{\to}(I-1)^{+}$ E1 transitions linking states of the yrast and negative-parity bands at high spin and the presence of an additional even-spin, positive-parity band deexciting exclusively to the negative parity sequence. The observations appear to be consistent with expectations based on the recently proposed concept of octupole phonon condensation.