Isotopic dependence of the giant monopole resonance in the even-A ^{112-124}Sn isotopes and the asymmetry term in nuclear incompressibility

TL;DR

This study measures the giant monopole resonance in Sn isotopes to explore the asymmetry term in nuclear incompressibility, revealing discrepancies with theoretical models and estimating the asymmetry parameter.

Contribution

It provides new experimental data on GMR energies in Sn isotopes and extracts the asymmetry term in nuclear incompressibility, highlighting limitations of current models.

Findings

GMR energies in Sn isotopes are lower than theoretical predictions.

A value of K_tau = -550 ± 100 MeV is derived for the asymmetry term.

Experimental data challenges existing nuclear incompressibility models.

Abstract

The strength distributions of the giant monopole resonance (GMR) have been measured in the even-A Sn isotopes (A=112--124) with inelastic scattering of 400-MeV $\alpha$ particles in the angular range $0^\circ$--$8.5^\circ$. We find that the experimentally-observed GMR energies of the Sn isotopes are lower than the values predicted by theoretical calculations that reproduce the GMR energies in $^{208}$Pb and $^{90}$Zr very well. From the GMR data, a value of $K_{\tau} = -550 \pm 100$ MeV is obtained for the asymmetry-term in the nuclear incompressibility.