Equation of state of nuclear matter from empirical constraints

2017

Phys. Rev. C

Predictions for the interaction part of the symmetry energy obtained from microscopic approaches based upon different foundations are reviewed and discussed in the light of recent updated constraints obtained from reaction observables in the ASY-EOS experiment at GSI. The discussion is then extended to the neutron skin thickness in 208 Pb and its relation to the density derivatives of the symmetry energy at and below saturation density. With regard to the latter, the main point is to demonstrate the importance of proper consideration of the theoretical uncertainties of microscopic predictions in order to guide phenomenological analyses.

“…First, the EoS will be built using empirical parametrizations taken from Ref. [37] or Ref. [38] for the isospin-symmetric part, whereas the symmetry energy is as in Eq.…”

Section: Predictions and Discussionmentioning

confidence: 99%

“…[37], fitted to K 0 =240 MeV, where K 0 is the incompressibility of nuclear matter, and those from Ref. [38], with K 0 = (240 ± 20) MeV.…”

Section: Predictions and Discussionmentioning

confidence: 99%

Comparing symmetry energy predictions and recent constraints from the ASY-EOS experiment at GSI

2017

Phys. Rev. C

“…In order to emphasize the role of the pure neutron matter EoS, which is our main goal here, we use an empirical EoS for symmetric nuclear matter (SNM) that we take from Ref. [36]. In this way, we separate out the role of neutron matter pressure and remove any model dependence originating from the details of the saturation point of SNM.…”

Section: Resultsmentioning

confidence: 99%

“…Note that, for the EoS of NM, the steps from LO to N 2 LO are free from inconsistencies. The phenomenological EoS of SNM is obtained from a Skyrme-type energy density functional and has a realistic saturation point at ρ 0 =0.16 fm −3 with energy per particle equal to -16.0 MeV [36]. Figure 2 shows the binding energy per nucleon as a function of the mass number for neutron-rich isotopes of Oxygen, Magnesium, and Aluminum.…”

Section: Resultsmentioning

confidence: 99%

Impact of the neutron matter equation of state on neutron skins and neutron drip lines in chiral effective field theory

Nosyk

2016

Phys. Rev. C

We present predictions of the binding energy per nucleon and the neutron skin thickness in highly neutron-rich isotopes of Oxygen, Magnesium, and Aluminum. The calculations are carried out at and below the neutron drip line as predicted by our model. The nuclear properties are obtained via an energy functional whose input is the equation of state of isospin-asymmetric infinite matter. The latter is based on a microscopic derivation of the energy per particle in neutron matter applying chiral few-nucleon forces together with a phenomenological model for the equation of state of symmetric nuclear matter. We highlight the impact of the neutron matter equation of state at different orders of chiral effective field theory on neutron skins and the binding energy per particle and quantify the uncertainty carried by our predictions.

“…We end these comments by stressing again the importance of complete calculations at each order beyond the Hartree-Fock approximation in order to reach definite conclusions on the convergence pattern of the neutron skin. We repeated the calculations adopting, this time, the empirical EoS from [22] for SNM. The latter is obtained from a Skyrme-type energy density functional and has a realistic saturation point at ρ 0 = 0.16 fm −3 with energy per particle equal to −16.0 MeV.…”

Section: Using a Phenomenological Eos For Symmetric Nuclear Mattermentioning

confidence: 99%

Uncertainty Analysis of 208Pb Neutron Skin Predictions with Chiral Interactions

2015

Symmetry

We report predictions for the neutron skin in 208 Pb using chiral two-and three-body interactions at increasing orders of chiral effective field theory and varying resolution scales. Closely related quantities, such as the slope of the symmetry energy, are also discussed. The sensitivity of the skin to just pure neutron matter pressure when going from order 2 to order 4 of chiral effective theory is singled out in a set of calculations that employ an empirical equation of state for symmetric nuclear matter.