Nuclear Theory·nucl-th

Thursday·July 27, 2017

8 papers—3 primary·5 cross-listed

01
[Submitted on 25 Jul 2017]
A new statistical method for the structure of the inner crust of neutron stars
A. Pastore · M. Shelley · S. Baroni · C. A. Diget
We investigated the structure of the low density regions of the inner crust of neutron stars using the Hartree-Fock-Bogoliubov (HFB) model to predict the proton content $Z$ of the nuclear clusters and, together with the lattice spacing, the proton content of the crust as a function of the total baryonic density $ρ_{b}$ . The exploration of the energy surface in the $(Z, ρ_{b})$ configuration space and the search for the local minima require thousands of calculations. Each of them implies an HFB calculation in a box with a large number of particles, thus making the whole process very demanding. In this work, we apply a statistical model based on a Gaussian Process Emulator that makes the exploration of the energy surface ten times faster. We also present a novel treatment of the HFB equations that leads to an uncertainty on the total energy of $\approx 4$ keV per particle. Such a high precision is necessary to distinguish neighbour configurations around the energy minima.
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
1707.08142 [pdf]
J.Phys.G(2017)·15 citations
02
[Submitted on 26 Jul 2017]
Superfluid neutron matter in the s-channel exchange nucleon-nucleon interaction models
M. I. Krivoruchenko🇷🇺
The superfluid pairing gap of neutron matter is calculated in the framework of Quark Compound Bag model with nucleon-nucleon interactions generated by the s-channel exchange of Jaffe-Low primitives (6-quark states).
Comments:
10 pages, REVTeX. Presented as a part of invited talks at Conference on Isospin, Structure, Reactions and Energy of Symmetry (ISTROS), Casta - Papiernicka, Casta, Slovakia, May 14 - 19, 2017 and Workshop on Spectroscopy and Reactions of Exotic Nuclei (Huzhou-CUSTIPEN), Huzhou, China, July 3 - 9, 2017
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1707.08424 [pdf]
0 citations
03
[Submitted on 26 Jul 2017]
Constraining the equation of state with identified particle spectra
Akihiko Monnai🇫🇷 · Jean-Yves Ollitrault🇫🇷
We show that in a central nucleus-nucleus collision, the variation of the mean transverse mass with the multiplicity is determined, up to a rescaling, by the variation of the energy over entropy ratio as a function of the entropy density, thus providing a direct link between experimental data and the equation of state. Each colliding energy thus probes the equation of state at an effective entropy density, whose approximate value is $19$ fm $^{- 3}$ for Au+Au collisions at 200 GeV and $41$ fm $^{- 3}$ for Pb+Pb collisions at 2.76 TeV, corresponding to temperatures of $227$ MeV and $279$ MeV if the equation of state is taken from lattice calculations. The relative change of the mean transverse mass as a function of the colliding energy gives a direct measure of the pressure over energy density ratio $P / ϵ$ , at the corresponding effective density. Using RHIC and LHC data, we obtain $P / ϵ = 0.21 \pm 0.10$ , in agreement with the lattice value $P / ϵ = 0.23$ in the corresponding temperature range. Measurements over a wide range of colliding energies using a single detector with good particle identification would help reducing the error.
Comments:
12 pages, 8 figures; minor revision
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1707.08466 [pdf]
PRC(2017)·17 citations

Affiliations

first authorsco-authorsvia INSPIRE

A new statistical method for the structure of the inner crust of neutron stars

Superfluid neutron matter in the s-channel exchange nucleon-nucleon interaction models

Constraining the equation of state with identified particle spectra

Affiliations