Incompressibility of Nuclear Matter from the Giant Monopole Resonance

$E0\mathrm{}$ 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 $\alpha$ particles between $0°\le {\theta }_{\mathrm{lab}}\le 6°$ to greater precision than previously available. In Sn, Sm, and Pb, $E0\mathrm{}$ 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 $231\pm 5\mathrm{MeV}$. Previous data gave an average of 215 MeV and the value for different nuclei disagreed by up to 40 MeV.