Nuclear Theory·nucl-th

Wednesday·January 29, 2020

16 papers—9 primary·7 cross-listed

01
[Submitted on 27 Jan 2020]
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.
Comments:
12 pages, 9 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2001.09997 [pdf]
EPJA(2020)·6 citations
02
[Submitted on 27 Jan 2020]
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.
Comments:
10 pages, 2 tables
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2001.10095 [pdf]
International Workshop on Nuclear Theory …
03
[Submitted on 28 Jan 2020]
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.
Comments:
13 pages, 11 figures, 2 tables; added calculations of shear viscosity and eta/s ratio of the parton systems under study
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2001.10140 [pdf]
PRC(2020)·10 citations
04
[Submitted on 28 Jan 2020]
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.
Comments:
13 pages, 11 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2001.10143 [pdf]
ApJ(2020)·94 citations
05
[Submitted on 28 Jan 2020]
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.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2001.10215 [pdf]
NPA(2020)·14 citations
06
[Submitted on 28 Jan 2020]
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.
Comments:
4 pages, 2 figures, Quark Matter 2019 proceeding
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2001.10226 [pdf]
NPA(2021)·1 citation
07
[Submitted on 28 Jan 2020]
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.
Comments:
19 pages, 12 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
2001.10259 [pdf]
PRC(2020)·62 citations
08
[Submitted on 28 Jan 2020]
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.
Comments:
References updated
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2001.10260 [pdf]
NPA(2021)·6 citations
09
[Submitted on 28 Jan 2020]
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.
Comments:
46 pages, 15 figures, contribution to 'Frontiers in Physics'
Subjects:
Nuclear Theory (nucl-th); Strongly Correlated Electrons (cond-mat.str-el); Computational Physics (physics.comp-ph)
arXiv:
2001.10433 [pdf]
Front.in Phys.(2020)·102 citations
10
[Submitted on 27 Jan 2020] (cross-list from hep-ph)
Anisotropic momentum broadening in the 2+1D Glasma: analytic weak field approximation and lattice simulations
Andreas Ipp🇦🇹 · David I. Müller🇦🇹 · Daniel Schuh🇦🇹
In heavy ion collisions, transverse momentum broadening quantifies the modification of a hard probe due to interactions with the quark-gluon plasma (QGP). We calculate momentum broadening in the Glasma, which is the highly non-isotropic precursor stage of the QGP right after the collision. We show that the Glasma leads to anisotropic momentum broadening: high energy partons accumulate more momentum along the beam axis than transverse to it. The physical origin of anisotropic broadening can be traced back to differences in the shapes of chromo-electric and chromo-magnetic flux tubes in the Glasma. We provide semi-analytic results for momentum broadening in the dilute Glasma and numerical results from real-time lattice simulations of the non-perturbative dense Glasma.
Comments:
25 pages, 8 figures; v2: accepted in PRD, new figure 5, fixed typos
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2001.10001 [pdf]
PRD(2020)·68 citations
11
[Submitted on 27 Jan 2020] (cross-list from hep-ph)
Hard probes of non-equilibrium quark-gluon plasma
Sigtryggur Hauksson🇨🇦 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦
Jets and photons could play an important role in finding the transport coefficients of the quark-gluon plasma. To this end we analyze their interaction with a non-equilibrium quark-gluon plasma. Using new field-theoretical tools we derive two-point correlators for the plasma which show how instabilities evolve in time. This allows us, for the first time, to derive finite rates of interaction with the medium. We furthermore show that coherent, long-wavelength instability fields in the Abelian limit do not modify the rate of photon emission or jet-medium interaction.
Comments:
4 pages, proceedings for Quark Matter 2019
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2001.10046 [pdf]
NPA(2021)·5 citations
12
[Submitted on 28 Jan 2020] (cross-list from hep-ph)
Photon induced K $Λ$ production on the proton in the low energy region
A. Fatima🇮🇳 · Z. Ahmad Dar🇮🇳 · M. Sajjad Athar🇮🇳 · S. K. Singh🇮🇳
The associated photoproduction of $K Λ$ from the proton in the low energy region is studied using an isobar model in which the non-resonant contributions are obtained from the non-linear sigma model with chiral SU(3) symmetry which predicts, in a natural way, the contact term with its coupling strength along with the coupling strengths of the various Born terms predicted by the non-linear sigma model. The present model is an extension of the non-linear sigma model with chiral SU(2) symmetry, used earlier to study the photo, electro, and neutrino productions of pions. In the resonance sector, the contributions from the well established nucleon resonances ( $R$ ) in the $s$ channel, the hyperon resonances ( $Y^{*}$ ) in the $u$ channel, and the kaon resonances ( $K^{*}$ and $K_{1}$ ) in the $t$ channel having spin $\leq \frac{3}{2}$ and mass $< 2$ GeV with a significant branching ratio in $K Λ$ decay mode, have been considered. The strong and electromagnetic couplings of the $s$ channel nucleon resonances are taken from experiments while the couplings for the resonances in the $t$ and $u$ channels are fitted to reproduce the current data on the associated photoproduction of $K Λ$ in this energy region. The numerical results are presented for the total and differential cross sections and are compared with the available experimental data from CLAS and SAPHIR as well as with some of the recent theoretical models.
Comments:
40 pages, 10 figure
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2001.10201 [pdf]
IJMPE(2020)·12 citations
13
[Submitted on 28 Jan 2020] (cross-list from hep-ph)
Comment on "Heavy Quarkonium in Extreme Conditions"
Masayuki Asakawa🇯🇵
In a recent paper (arXiv:1912.02253), Rothkopf claims that the Bryan method, which is widely used to obtain the solution in the maximum entropy method and makes use of the singular value decomposition of a matrix, limits the search space for the solution. He even presents a counterexample to the Bryan method. In this comment, we first recapitulate the mathematical basis of the Bryan method, and reconfirm that it makes use of no approximations and that it is therefore mathematically rigorous. In the second part, we explicitly show that Rothkopf's ``counterexample'' actually does not constitute a counterexample on the basis of the definition of singular value decomposition itself.
Comments:
3 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2001.10205 [pdf]
7 citations
14
[Submitted on 28 Jan 2020] (cross-list from hep-ph)
Coulomb-nuclear interference in elastic scattering: eikonal calculation to all orders of $α$
Jan Kašpar🇨🇿
The Coulomb-nuclear interference (CNI) has recently been used by the TOTEM Collaboration to analyse proton-proton elastic-scattering data from the LHC and to draw physics conclusions. This paper will present an eikonal calculation of the CNI effects performed to all orders of the fine structure constant, $α$ . This calculation will be used as a reference to benchmark several widely-used CNI formulae and to verify several recent claims by other authors.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2001.10227 [pdf]
Acta Phys.Polon.B(2021)·9 citations
15
[Submitted on 28 Jan 2020] (cross-list from nucl-ex)
In-beam gamma-ray and electron spectroscopy of $^{249, 251}$ Md
R. Briselet🇫🇷 · Ch. Theisen🇫🇷 · B. Sulignano🇫🇷 · M. Airiau🇫🇷 · K. Auranen🇫🇮 · D. M. Cox🇫🇮 · F. Déchery🇫🇷 · A. Drouart🇫🇷 · Z. Favier🇫🇷 · B. Gall🇫🇷 · T. Goigoux🇫🇷 · T. Grahn🇫🇮 and 31 other authors
The odd- $Z$ $^{251}$ Md nucleus was studied using combined $γ$ -ray and conversion-electron in-beam spectroscopy. Besides the previously observed rotational band based on the $[521] 1/ 2^{-}$ configuration, another rotational structure has been identified using $γ$ - $γ$ coincidences. The use of electron spectroscopy allowed the rotational bands to be observed over a larger rotational frequency range. Using the transition intensities that depend on the gyromagnetic factor, a $[514] 7/ 2^{-}$ single-particle configuration has been inferred for this band, i.e., the ground-state band. A physical background that dominates the electron spectrum with an intensity of $≃$ 60% was well reproduced by simulating a set of unresolved excited bands. Moreover, a detailed analysis of the intensity profile as a function of the angular momentum provided a method for deriving the orbital gyromagnetic factor, namely $g_{K} = 0.6 9_{- 0.16}^{+ 0.19}$ for the ground-state band. The odd- $Z$ $^{249}$ Md was studied using $γ$ -ray in-beam spectroscopy. Evidence for octupole correlations resulting from the mixing of the $Δ l = Δ j = 3$ $[521] 3/ 2^{-}$ and $[633] 7/ 2^{+}$ Nilsson orbitals were found in both $^{249, 251}$ Md. A surprising similarity of the $^{251}$ Md ground-state band transition energies with those of the excited band of $^{255}$ Lr has been discussed in terms of identical bands. Skyrme-Hartree-Fock-Bogoliubov calculations were performed to investigate the origin of the similarities between these bands.
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2001.10235 [pdf]
PRC(2020)·10 citations
16
[Submitted on 28 Jan 2020] (cross-list from astro-ph.HE)
Equation of State and Progenitor Dependence of Stellar-Mass Black-Hole Formation
A.S. Schneider · E. O'Connor · E. Granqvist · A. Betranhandy · S.M. Couch
The core collapse of a massive star results in the formation of a proto-neutron star (PNS). If enough material is accreted onto a PNS it will become gravitationally unstable and further collapse into a black-hole (BH). We perform a systematic study of failing core-collapse supernovae in spherical symmetry for a wide range of presupernova progenitor stars and equations of state (EOSs) of nuclear matter. We analyze how variations in progenitor structure and the EOS of dense matter above nuclear saturation density affect the PNS evolution and subsequent BH formation. Comparisons of core-collapse for a given progenitor star and different EOSs show that the path traced by the PNS in mass-entropy phase space $M_{grav}^{PNS} - s ~$ is well correlated with the progenitor compactness and almost EOS independent, apart from the final endpoint. Furthermore, BH formation occurs, to a very good approximation, soon after the PNS overcomes the maximum \textit{gravitational} mass supported by a hot NS with constant entropy equal to $s ~$ . These results show a path to constraining the temperature dependence of the EOS through the detection of neutrinos from a failed galactic supernova.
Comments:
22 pages, 13 figures, 3 tables
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2001.10434 [pdf]
ApJ(2020)·74 citations

Affiliations

first authorsco-authorsvia INSPIRE