Nuclear Theory·nucl-th

Wednesday·January 29, 2020

16 papers—9 primary·7 cross-listed

01
Shape isomers in Pt, Hg and Pb isotopes with N $\leq$ 126
Krzysztof Pomorski🇵🇱 · Bozena Nerlo-Pomorska🇵🇱 · Artur Dobrowolski🇵🇱 · Johann Bartel🇫🇷 · Costel M. Petrache🇫🇷
Deformation-energy surfaces of 54 even-even isotopes of Pt, Hg and Pb nuclei with neutron numbers up to 126 are investigated within a macroscopic-microscopic model based on the Lublin-Strasbourg-Drop macroscopic energy and shell plus pairing-energy corrections obtained from a Yukawa-folded mean-field potential at the desired deformation. A new, rapidly converging Fourier shape parametrization is used to describe nuclear shapes. The stability of shape isomeric states with respect to non-axial and higher-order deformations is investigated.
nucl-thnucl-exEPJA(2020)·6 citations
02
Bohr Hamiltonian with Hulthén plus ring-shaped potential for triaxial nuclei with deformation-dependent mass term
A. Adahchour · S. Ait El Korchi · A. El Batoul · A. Lahbass · M. Oulne
In this work, we solve the eigenvalues problem with the Bohr collective Hamiltonian for triaxial nuclei within Deformation-Dependent Mass formalism (DDM) using the Hulthén potential. We shall call the solution developed here Z(5)-HDDM. Analytical expressions for energy spectra are derived by means of a recent version of the Asymptotic Iteration Method. The calculated numerical results are compared with the experimental data, and the model Z(5)-H using the Hulthén potential without DDM formalism as well as theoretical predictions of Z(5)-DDDM model with Davidson potential.
nucl-thInternational Workshop on Nuclear Theory …
03
Validation and improvement of the ZPC parton cascade inside a box
Xin-Li Zhao🇨🇳 · Guo-Liang Ma🇨🇳 · Yu-Gang Ma🇨🇳 · Zi-Wei Lin🇺🇸
Cascade solutions of the Boltzmann equation suffer from causality violation at large densities and/or scattering cross sections. Although the particle subdivision technique can reduce the causality violation, it alters event-by-event correlations and fluctuations and is also computationally expensive. Here we evaluate and then improve the accuracy of the ZPC parton cascade for elastic scatterings inside a box without using parton subdivision. We first test different collision schemes for the collision times and ordering time and find that the default collision scheme does not accurately describe the equilibrium momentum distribution at large opacities. We then find a specific collision scheme that can describe very accurately the equilibrium momentum distribution as well as the time evolution towards equilibrium, even at large opacities. We also calculate the shear viscosity and the $η / s$ ratio of the parton systems and confirm that the new collision scheme is more accurate. In addition, we use a novel parton subdivision method to obtain the "exact" evolution of the system. This subdivision method is valid for such box calculations and is so much more efficient than the standard subdivision method that we use a subdivision factor of $1 0^{6}$ in this study.
nucl-thhep-phPRC(2020)·10 citations
04
Effects of symmetry energy on equation of state for simulations of core-collapse supernovae and neutron-star mergers
Hong Shen · Fan Ji · Jinniu Hu · Kohsuke Sumiyoshi
We construct a new equation of state (EOS) for numerical simulations of core-collapse supernovae and neutron-star mergers based on an extended relativistic mean-field model with a small symmetry energy slope $L$ , which is compatible with both experimental nuclear data and recent observations of neutron stars. The new EOS table (EOS4) based on the extended TM1 (TM1e) model with $L = 40$ MeV is designed in the same tabular form and compared with the commonly used Shen EOS (EOS2) based on the original TM1 model with $L = 110.8$ MeV. This is convenient and useful for performing numerical simulations and examining the influences of symmetry energy and its density dependence on astrophysical phenomena. In comparison with the TM1 model used in EOS2, the TM1e model provides a similar maximum neutron-star mass but smaller radius and tidal deformability for a $1.4 M_{⊙}$ neutron star, which is more consistent with current constraints. By comparing the phase diagram and thermodynamic quantities between EOS4 and EOS2, it is found that the TM1e model predicts relatively larger region of nonuniform matter and softer EOS for neutron-rich matter. Significant differences between EOS4 and EOS2 are observed in the case with low proton fraction, while the properties of symmetric matter remain unchanged.
nucl-thastro-ph.HEApJ(2020)·94 citations
05
Microscopic study of the Shell Structure evolution in isotopes of light to middle mass range Nuclides
Virender Thakur · Pankaj Kumar · Suman Thakur · Smriti Thakur · Vikesh Kumar · Shashi K Dhiman
The shell structure of even-even isotopes in Si, S, Ar and Ca has been analysed. The theoretical calculations of shell closure parameter $D_{n} (N)$ and the differential variation of the two-neutron separation energy $d S_{2 n} (Z, N)$ are carried out within the framework of Hartree-Fock-Bogoliubov theory. Calculations are carried out for different skyrme forces and their sensitivity has been tested. Same nuclides are studied by employing the relativistic mean field aproach based on meson exchange and point coupling models. Theoretically calculated estimates are in good agreement with the recently available experimental data which fortifies signature of shell closure at N = 14 and 20 in case of Si, N = 14, 20 and 28 in S and N=20 and 28 in Ar and Ca isotopes.
nucl-thNPA(2020)·14 citations
06
Longitudinal fluid response and pseudorapidity dependent flow in relativistic heavy-ion collisions
Hui Li🇨🇳 · Li Yan🇨🇳
We study the pseudorapidity dependent hydrodynamic response in heavy-ion collisions. A differential hydrodynamic relation is obtained for elliptic flow. Using event-by-event simulations of 3+1D MUSIC, with initial conditions generated via a multi-phase transport (AMPT) model, the differential response relation is verified. Based on the response relation, we find that the two-point correlation of elliptic flow in pseudorapidity are separated into the fluid response and the two-point correlation of initial eccentricity.
nucl-thNPA(2021)·1 citation
07
Multi-messenger and multi-physics Bayesian inference for GW170817 binary neutron star merger
H. Güven🇫🇷 · K. Bozkurt🇫🇷 · E. Khan🇫🇷 · J. Margueron🇫🇷
The tidal deformability probability distribution extracted from GW170817 alone, or including multi-messenger information, is confronted to astrophysical and nuclear physics additional constraints within a semi-agnostic approach for the dense matter equation of state. We use Bayesian statistics to combine together low density nuclear physics data, such as the ab-initio predictions based on $χ$ EFT interactions or the isoscalar giant monopole resonance, and astrophysical constraints from neutron stars, such as the maximum mass of neutron stars or the probability density function of the tidal deformability $Λ ~$ obtained from the GW170817 event. The posteriors probability distribution functions are marginalized over several nuclear empirical parameters ( $L_{sym}$ , $K_{sym}$ , $Q_{sat}$ and $Q_{sym}$ ), as well as over observational quantities such as the $1.4 M_{⊙}$ radius $R_{1.4}$ and the pressure at twice the saturation density $P (2 n_{sat})$ . The correlations between $L_{sym}$ and $K_{sym}$ and between $K_{sat}$ and $Q_{sat}$ are also further analyzed. Tension is found between the posteriors: the first one is localized in the tidal deformability probability distribution itself, depending whether multi-messenger analysis is included or not, and the second one is between the observational data and the nuclear physics inputs. These tensions impact the predictions for $L_{sym}$ , $K_{sym}$ and $R_{1.4}$ with centroids which differ by 2-3 $σ$ . Implications for the nuclear equation of state are also discussed.
nucl-thastro-ph.HEastro-ph.SRPRC(2020)·62 citations
08
Flow in collisions of light nuclei
Wojciech Broniowski🇵🇱 · Piotr Bożek🇵🇱 · Maciej Rybczyński🇵🇱 · Enrique Ruiz Arriola🇪🇸
In this talk we discuss several interesting aspects of collective flow in small systems in reference to planned future experiments. First, we bring in the novel possibility of exploring elliptic flow with heavy nuclei collisions on polarized deuteron targets, accessible in AFTER@LHC program after Long Shutdown 3. Then we pass to the Glauber model predictions for the presently considered $^{16} O -^{16} O$ program and RHIC and the LHC. Finally, we turn to our previous proposal concerning specific flow signatures of intrinsic correlations (such as the supposed $α$ clusterization) in the structure of light nuclei in collisions with heavy nuclei. In particular, $^{12} C$ --heavy nucleus ultrarelativistic reactions would provide insight into the ground-state $^{12} C$ structure, complementary to the traditional nuclear structure features.
nucl-thnucl-exNPA(2021)·6 citations
09
Many-body perturbation theories for finite nuclei
Alexander Tichai🇩🇪 · Robert Roth🇩🇪 · Thomas Duguet🇫🇷
In recent years many-body perturbation theory encountered a renaissance in the field of ab initio nuclear structure theory. In various applications it was shown that perturbation theory, including novel flavors of it, constitutes a useful tool to describe atomic nuclei, either as a full-fledged many-body approach or as an auxiliary method to support more sophisticated non-perturbative many-body schemes. In this work the current status of many-body perturbation theory in the field of nuclear structure is discussed and novel results are provided that highlight its power as a efficient and yet accurate (pre-processing) approach to systematically investigate medium-mass nuclei. Eventually a new generation of chiral nuclear Hamiltonians is benchmarked using several state-of-the-art flavours of many-body perturbation theory.
nucl-thcond-mat.str-elphysics.comp-phFront.in Phys.(2020)·102 citations

Affiliations

first authorsco-authorsvia INSPIRE