Laboratory Tests of Low Density Astrophysical Equations of State

Abstract

Clustering in low density nuclear matter has been investigated using the\nNIMROD multi-detector at Texas A&M University. Thermal coalescence modes were\nemployed to extract densities, $\\rho$, and temperatures, $T$, for evolving\nsystems formed in collisions of 47 $A$ MeV $^{40}$Ar + $^{112}$Sn,$^{124}$Sn\nand $^{64}$Zn + $^{112}$Sn, $^{124}$Sn. The yields of $d$, $t$, $^{3}$He, and\n$^{4}$He have been determined at $\\rho$ = 0.002 to 0.032 nucleons/fm$^{3}$ and\n$T$= 5 to 10 MeV. The experimentally derived equilibrium constants for $\\alpha$\nparticle production are compared with those predicted by a number of\nastrophysical equations of state. The data provide important new constraints on\nthe model calculations.\n