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
04
[Submitted on 24 Jul 2017] (cross-list from hep-th)
Integrability and chemical potential in the (3+1)-dimensional Skyrme model
P. D. Alvarez🇨🇱 · F. Canfora🇨🇱 · N. Dimakis🇨🇱 · A. Paliathanasis🇨🇱
Using a remarkable mapping from the original (3+1)dimensional Skyrme model to the Sine-Gordon model, we construct the first analytic examples of Skyrmions as well as of Skyrmions--anti-Skyrmions bound states within a finite box in 3+1 dimensional flat space-time. An analytic upper bound on the number of these Skyrmions--anti-Skyrmions bound states is derived. We compute the critical isospin chemical potential beyond which these Skyrmions cease to exist. With these tools, we also construct topologically protected time-crystals: time-periodic configurations whose time-dependence is protected by their non-trivial winding number. These are striking realizations of the ideas of Shapere and Wilczek. The critical isospin chemical potential for these time-crystals is determined.
Comments:
15 pages; 1 figure; a discussion on the closeness to the topological bound as well as some clarifying comments on the semi-classical quantization have been included. Relevant references have been added. Version accepted for publication on Physics Letters B
Subjects:
High Energy Physics — Theory (hep-th); cond-mat.other (cond-mat.other); Mathematical Physics (math-ph); math.MP (math.MP); Nuclear Theory (nucl-th)
arXiv:
1707.07421 [pdf]
PLB(2017)·53 citations
05
[Submitted on 26 Jul 2017] (cross-list from nucl-ex)
Muon capture reaction on $^{100} M o$ to study nuclear responses for double beta decays and astro-neutrinos
I.H. Hashim · H. Ejiri · T. Shima · A. Sato · Y. Kuno · N. Kawamura · S. Miyake · K. Ninomiya
The negative-muon capture reaction (MCR) on the enriched $^{100} M o$ isotope was studied for the first time to investigate neutrino nuclear response for neutrino-less double beta decays and supernova neutrino nuclear interactions. MCR on $^{100} M o$ proceeds mainly as $^{100} M o (m u, x n)^{100 - x} N b$ with $x$ being the number of neutrons emitted from MCR. The Nb isotope mass distribution was obtained by measuring delayed gamma-rays from radioactive $^{100 - x} N b$ . By using the neutron emission model after MCR, the neutrino response (the strength distribution) for MCR was derived. Giant resonance (GR)-like distribution at the peak energy around 11-14 MeV, suggests concentration of the MCR strength at the muon capture GR region.
Comments:
5 pages, 6 figures
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1707.08363 [pdf]
PRC(2018)·41 citations
06
[Submitted on 26 Jul 2017] (cross-list from hep-ph)
Non-extensive Fokker-Planck transport coefficients of heavy quarks
Trambak Bhattacharyya🇿🇦 · Jean Cleymans🇿🇦
In presence of the non-ideal plasma effects, Heavy Quarks (HQs) carry out non linear random walk inside Quark-Gluon Plasma (QGP) and in the small momentum transfer limit, the evolution of the HQ distribution is dictated by the Non Linear Fokker-Planck Equation (NLFPE). Using the NLFPE, we calculate the transport coefficients (drag and diffusion) of heavy quarks travelling through QGP. We observe substantial modification in the momentum and temperature variation of the transport coefficients; and this will modify the physical picture we are having about the transport of heavy quarks inside QGP, and hence, about the characterisation of the plasma.
Comments:
9 pages, 8 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1707.08425 [pdf]
3 citations
07
[Submitted on 26 Jul 2017] (cross-list from hep-ph)
Hydrodynamical corrections to electromagnetic emissivities in QCD
Yizhuang Liu🇺🇸 · Ismail Zahed🇺🇸
We provide a general framework for the derivation of the hydrodynamical corrections to the QCD electromagnetic emissivities in a viscous fluid. Assuming that the emission times are short in comparison to the fluid evolution time, we show that the leading corrections in the fluid gradients are controlled by the bulk and shear tensors times pertinent response functions involving the energy-momentum tensor. In a hadronic fluid phase, we explicit these contributions using spectral functions. Using the vector dominance approximation, we show that the bulk viscosity correction to the photon rate is sizable, while the shear viscosity is negligible for about all frequencies. In the partonic phase near the transition temperature we provide an assessment of the viscous corrections to the photon and dilepton emissions, using a non-perturbative quark-gluon plasma with soft thermal gluonic corrections in the form of operators of leading mass dimension. Again, the thermal bulk viscosity corrections are found to be larger than the thermal shear viscosity corrections at all energies for both the photon and dilepton in the partonic phase.
Comments:
20 pages, 5 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1707.08523 [pdf]
PRD(2017)·6 citations
08
[Submitted on 26 Jul 2017] (cross-list from hep-ph)
Dynamic Universality Class of Model H with Frustrated Diffusion: $ϵ$ -Expansion
Ho-Ung Yee🇺🇸
We study a variation of the dynamic universality class of model H in a spatial dimension of $d = 4 - ϵ$ , by frustrating charge diffusion and momentum density fluctuations along $d_{T} = 1$ or $d_{T} = 2$ dimensions, while keeping the same dynamics of model H in the other $d_{L} = d - d_{T}$ dimensions. The case of $d_{T} = 2$ describes the QCD critical point in a background magnetic field. We find that these models belong to a different dynamical universality class due to extended conservation laws compared to the model H, although the static universality class remains the same as the 3-dimensional Ising model. We compute the dynamic critical exponents of these models in first order of $ϵ$ -expansion to find that $x_{λ} \approx 0.847 ϵ$ , $x_{η ˉ} \approx 0.153 ϵ$ , and $z = 4 - x_{λ} \approx 3.15$ when $ϵ = 1$ and $d_{T} = 2$ . For $d_{T} = 1$ the results are numerically similar to the model H values: $z \approx 3.08$ .
Comments:
15 pages, 3 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1707.08560 [pdf]
PRD(2018)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE