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arXiv · 0812.4499

Incompressibility of neutron-rich matter

J. Piekarewicz·M. Centelles
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Abstract

The saturation properties of neutron-rich matter are investigated in a relativistic mean-field formalism using two accurately calibrated models: NL3 and FSUGold. The saturation properties - density, binding energy per nucleon, and incompressibility coefficient - are calculated as a function of the neutron-proton asymmetry alpha=(N-Z)/A to all orders in alpha. Good agreement (at the 10% level or better) is found between these numerical calculations and analytic expansions that are given in terms of a handful of bulk parameters determined at saturation density. Using insights developed from the analytic approach and a general expression for the incompressibility coefficient of infinite neutron-rich matter, i.e., K0(alpha)=K0+Ktau*alpha^{2}+..., we construct a Hybrid model with values for K0 and Ktau as suggested by recent experimental findings. Whereas the Hybrid model provides a better description of the measured distribution of isoscalar monopole strength in the Sn-isotopes relative to both NL3 and FSUGold, it significantly underestimates the distribution of strength in 208Pb. Thus, we conclude that the incompressibility coefficient of neutron-rich matter remains an important open problem.

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J. Piekarewicz, M. Centelles. 2009-04-15. Incompressibility of neutron-rich matter. https://doi.org/10.1103/physrevc.79.054311

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