Incompressibility of Nuclear Matter from the Giant Monopole Resonance

Abstract

$E0$ strength distributions in ${}^{90}\mathrm{Zr}$, ${}^{116}\mathrm{Sn}$, ${}^{144}\mathrm{Sm}$, and ${}^{208}\mathrm{Pb}$ have been measured with inelastic scattering of 240-MeV $\ensuremath{\alpha}$ particles between $0\ifmmode^\circ\else\textdegree\fi{}\ensuremath{\le}{\ensuremath{\theta}}_{\mathrm{lab}}\ensuremath{\le}6\ifmmode^\circ\else\textdegree\fi{}$ to greater precision than previously available. In Sn, Sm, and Pb, $E0$ strength was concentrated in approximately symmetric peaks, whereas in ${}^{90}\mathrm{Zr}$ it had a significant high energy tail. Comparing with microscopic calculations using the Gogny interaction, these and our previously reported results for ${}^{40}\mathrm{Ca}$ are consistent with a nuclear matter incompressibility of $231\ifmmode\pm\else\textpm\fi{}5\mathrm{MeV}$. Previous data gave an average of 215 MeV and the value for different nuclei disagreed by up to 40 MeV.