Splitting of ISGMR strength in the light-mass nucleus 24Mg due to ground-state deformation

Abstract

The isoscalar giant monopole resonance (ISGMR) strength distribution in 24Mg has been determined from background-free inelastic scattering of 386-MeV α particles at extreme forward angles, including 0∘. The ISGMR strength distribution has been observed for the first time to have a two-peak structure in a light-mass nucleus. This splitting of ISGMR strength is explained well by microscopic theory in terms of the prolate deformation of the ground state of 24Mg.