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

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+ 8 Li 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 9 Be.Results: A good fit of the 8 Li(p,p) 8 Li resonance elastic scattering excitation function was obtained using previously tentatively known 5/2 − T=3/2 state at 18.65 MeV in 9 Be 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.