Observation of T=3/2 Isobaric Analog States in 9Be using p+8Li resonance scattering

TL;DR

This study demonstrates that resonance scattering on a proton target effectively reveals the structure of neutron-rich exotic nuclei by identifying isobaric analog states, confirming isospin conservation, and expanding experimental techniques.

Contribution

The paper benchmarks the resonance scattering method for studying neutron-rich nuclei, identifying new broad T=3/2 states in 9Be, and confirms isospin as a good quantum number in this context.

Findings

Identified a new broad T=3/2 s-wave state at 18.5 MeV in 9Be.

Confirmed the validity of isospin conservation in highly excited states.

Validated resonance scattering as a promising approach for exotic nuclei studies.

Abstract

Background: Resonance scattering has been extensively used to study the structure of exotic, neutron-deficient nuclei. Extension of the resonance scattering technique to neutron-rich nuclei was suggested more than 20 years ago. This development is based on the isospin conservation law. In spite of broad field of the application, it has never gained a wide-spread acceptance. Purpose: To benchmark the experimental approach to study the structure of exotic neutron-rich nuclei through resonance scattering on a proton target. Method: The excitation function for p+8Li resonance scattering is measured using a thick target by recording coincidence between light and heavy recoils, populating T=3/2 isobaric analog states (IAS) in 9Be. Results: A good fit of the 8Li(p,p)8Li resonance elastic scattering excitation function was obtained using previously tentatively known 5/2- T=3/2 state at 18.65 MeV in 9Be and a new broad T=3/2 s-wave state - the 5/2+ at 18.5 MeV. These results fit the expected iso-mirror properties for the T=3/2 A=9 iso-quartet. Conclusions: Our analysis confirmed isospin as a good quantum number for the investigated highly excited T=3/2 states and demonstrated that studying the structure of neutron-rich exotic nuclei through IAS is a promising approach.