Electromagnetic M1 transition strengths from inelastic proton scattering: The cases of 48Ca and 208Pb

TL;DR

This paper presents a method to extract electromagnetic M1 transition strengths from inelastic proton scattering data, applied to 48Ca and 208Pb, providing insights into the spin-isospin response and quenching phenomena in nuclei.

Contribution

A novel approach using isospin symmetry to determine electromagnetic M1 strengths from proton scattering data, validated on key nuclei 48Ca and 208Pb.

Findings

M1 strength in 48Ca aligns with older (e,e') data.

Results exclude larger (γ,n) experiment values.

Good agreement with electromagnetic probes in 208Pb.

Abstract

Inelastic proton scattering at energies of a few hundred MeV and extreme forward angles selectively excites the isovector spin-flip M1 (IVSM1) resonance. A method based on isospin symmetry is presented to extract its electromagnetic transition strength from the (p,p') cross sections. It is applied to 48Ca, a key case for an interpretation of the quenching phenomenon of the spin-isospin response, and leads to a M1 strength consistent with an older (e,e') experiment excluding the almost two times larger value from a recent (\gamma,n) experiment. Good agreement with electromagnetic probes is observed in 208Pb suggesting the possibility to extract systematic information on the IVSM1 resonance in heavy nuclei.