Nuclear Theory·nucl-th

Friday·February 7, 2020

13 papers—7 primary·6 cross-listed

01
[Submitted on 6 Feb 2020]
Two quasiparticle wobbling in the even-even nucleus 130Ba
Y. K. Wang · F. Q. Chen · P. W. Zhao
Two newly observed bands built on a two-quasiparticle configuration in 130Ba have been investigated for the first time with the microscopic projected shell model. The experimental energy spectra and the available electromagnetic transition probabilities are well reproduced. The wobbling character of the higher band is revealed by the angular momentum projected wavefunctions via the K plot and the azimuthal plot. This provides the first strong microscopic evidence for wobbling motion based on a two-quasiparticle configuration in even-even nuclei.
Comments:
12 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2002.02093 [pdf]
PLB(2020)·29 citations
02
[Submitted on 6 Feb 2020]
Application of the coherent density fluctuation model to study the nuclear matter properties of finite nuclei within the relativistic mean-field formalism
Ankit Kumar🇮🇳 · H. C. Das🇮🇳 · Manpreet Kaur🇮🇳 · M. Bhuyan🇲🇾 · S. K. Patra🇮🇳
We obtained a density-dependent analytical expression of binding energy per nucleon for different neutron-proton asymmetry of the nuclear matter (NM) with a polynomial fitting, which manifests the results of effective field theory motivated relativistic mean-field (E-RMF) model. This expression has the edge over the Br $u ¨$ ckner energy density functional [Phys. Rev. {\bf 171}, 1188 (1968)] since it resolves the Coster-Band problem. The NM parameters like incompressibility, neutron pressure, symmetry energy, and its derivatives are calculated using the acquired expression of energy per nucleon. Further, the weight function calculated by E-RMF densities are folded with calculated NM parameters within coherent density fluctuation model to find the properties of closed/semi-closed-shell even-even $^{16}$ O, $^{40}$ Ca, $^{48}$ Ca, $^{56}$ Ni, $^{90}$ Zr, $^{116}$ Sn, and $^{208}$ Pb nuclei. The values obtained for the neutron pressure $P^{A}$ , symmetry energy $S^{A}$ and its derivative $L_{sy m}^{A}$ known as slope parameter, lie within a narrow domain whereas there is a large variation in isoscalar incompressibility $K^{A}$ and surface incompressibility $K_{sy m}^{A}$ while moving from light to heavy nuclei. The sizable variation in $K^{A}$ and $K_{sy m}^{A}$ for light and heavy nuclei depicts their structural dependence due to the peculiar density distribution of each nucleus. A comparison of surface quantities calculated in the present work has also been made with ones obtained via Br $u ¨$ ckner energy density functional.
Comments:
8 pages, 5 figures, 3 tables. Published in Phys. Rev. C 103 , 024305 (2021)
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2002.02135 [pdf]
PRC(2021)·13 citations
03
[Submitted on 6 Feb 2020]
Ab initio computation of charge densities for Sn and Xe isotopes
P. Arthuis🇬🇧 · C. Barbieri🇬🇧 · M. Vorabbi🇺🇸 · P. Finelli🇮🇹
We present the first ab initio calculations for open-shell nuclei past the tin isotopic line, focusing on Xe isotopes as well as doubly-magic Sn isotopes. We show that, even for moderately hard interactions, it is possible to obtain meaningful predictions and that the NNLOsat chiral interaction predicts radii and charge density distributions close to the experiment. We then make a new prediction for $^{100}$ Sn. This paves the way for ab initio studies of exotic charge density distributions at the limit of the present ab initio mass domain, where experimental data is becoming available. The present study closes the gap between the largest isotopes reachable by ab initio methods and the smallest exotic nuclei accessible to electron scattering experiments.
Comments:
6 pages, 4 figures and 2 tables
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2002.02214 [pdf]
PRL(2020)·68 citations
04
[Submitted on 5 Feb 2020]
Nuclear effects in proton transport and dose calculations
Francesc Salvat · José Manuel Quesada
Interactions of protons with nuclei are modeled in a form that is suitable for Monte Carlo simulation of proton transport. The differential cross section (DCS) for elastic collisions of protons with neutral atoms is expressed as the product of the Rutherford DCS, which describes scattering by a bare point nucleus, and two correction factors that account for the screening of the nuclear charge by the atomic electrons and for the effect of the structure of the nucleus. The screening correction is obtained by considering the scattering of the projectile by an atom with a point nucleus and the atomic electron cloud described by a parameterization of the Dirac-Hartree-Fock-Slater self-consistent electron density. The DCS for scattering by this point nucleus atom is calculated by means of the eikonal approximation. The nuclear correction to the DCS for elastic collisions is calculated by conventional partial-wave analysis with a global optical-model potential that describes the interaction with the bare nucleus. Inelastic interactions of the projectile with target nuclei are described by using information from data files in ENDF-6 format, which provide cross sections, multiplicities, and angle-energy distributions of all reaction products: light ejectiles (neutrons, protons, . . . ), gammas, as well as recoiling heavy residuals. These interaction data have been used in the Monte Carlo transport code PENH, an extension of the electron-gamma code PENELOPE, which originally accounted for electromagnetic interactions only. The combined code system PENH/PENELOPE performs simulations of coupled electron-photon-proton transport. A few examples of simulation results are presented to reveal the influence of nuclear interactions on proton transport processes and on the calculation of dose distributions from proton beams.
Subjects:
Nuclear Theory (nucl-th); physics.app-ph (physics.app-ph); Atomic Physics (physics.atom-ph)
arXiv:
2002.02300 [pdf]
Nucl.Instrum.Meth.B(2020)·4 citations
05
[Submitted on 6 Feb 2020]
Beyond-mean-field effects on the symmetry energy and its slope from the low-lying dipole response of $^{68}$ Ni
M. Grasso🇫🇷 · D. Gambacurta🇮🇹
We study low-energy dipole excitations in the unstable nucleus $^{68}$ Ni with the beyond-mean-field (BMF) subtracted second random-phase-approximation (SSRPA) model based on Skyrme interactions. First, strength distributions are compared with available experimental data and transition densities of some selected peaks are analyzed. The so-called isospin splitting is also discussed by studying the isoscalar/isovector character of such excitations. We estimate then in an indirect way BMF effects on the symmetry energy of infinite matter and on its slope starting from the BMF SSRPA low-lying strength distribution. For this, several linear correlations are used, the first one being a correlation existing between the contribution (associated with the low-energy strength) to the total energy-weighted sum rule (EWSR) and the slope of the symmetry energy. BMF estimates for the slope of the symmetry energy can be extracted in this way. Correlations between such a slope and the neutron-skin thickness of $^{68}$ Ni and correlations between the neutron-skin thickness of $^{68}$ Ni and the electric dipole polarizability times the symmetry energy are then used to deduce BMF effects on the symmetry energy.
Comments:
10 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2002.02331 [pdf]
PRC(2020)·12 citations
06
[Submitted on 5 Feb 2020]
A theoretical approach to study J/ $Ψ$ suppression in relativistic heavy ion collisions
Santosh K. Karn (Department of Physics, School of Basic Sciences and Research, Sharda University)🇮🇳
With a view to understanding J/ $Ψ$ suppression in relativistic heavy ion collisions, we compute the suppression rate within the framework of hydrodynamical evolution model. For this, we consider an ellipsoidal flow and use an ansatz for temperature profile function which accounts for time and the three dimensional space evolution of the quark-gluon plasma. We have calculated the survival probability separately as the function of transverse and longitudinal momentum. We have shown that previous calculations are special cases of this model.
Comments:
06 pages
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2002.02412 [pdf]
Open J.Microphys.(2020)·0 citations
07
[Submitted on 6 Feb 2020]
Constraints and correlations of nuclear matter parameters from a density-dependent van der Waals model
M. Dutra · B. M. Santos · O. Lourenço
A recently proposed density-dependent van der Waals model, with only $4$ free parameters adjusted to fix binding energy, saturation density, symmetry energy, and incompressibility, is analyzed under symmetric and asymmetric nuclear matter constraints. In a previous paper, it was shown that this model is fully consistent with the constraints related to the binary neutron star merger event named GW170817 and reported by the LIGO and Virgo collaboration. Here, we show that it also describes satisfactorily the low and high-density regions of symmetric nuclear matter, with all the main constraints satisfied. We also found a linear correlation between the incompressibility and the skewness parameter, both at the saturation density and show how it relates to the crossing point presented in the incompressibility as a function of the density. In the asymmetric matter regime, other linear correlations are found, namely, the one between the symmetry energy ( $J$ ) and its slope ( $L_{0}$ ), and other one establishing the symmetry energy curvature as a function of the combination given by $3 J - L_{0}$ .
Comments:
20 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2002.02437 [pdf]
J.Phys.G(2020)·12 citations
08
[Submitted on 5 Feb 2020] (cross-list from astro-ph.SR)
Universality and Non-Universality in Distributed Nuclear Burning in Homogeneous Isotropic Turbulence
Yossef Zenati · Robert T. Fisher
Nuclear burning plays a key role in a wide range of astrophysical stellar transients, including thermonuclear, pair instability, and core collapse supernovae, as well as kilonovae and collapsars. Turbulence is now understood to also play a key role in these astrophysical transients. Here we demonstrate that turbulent nuclear burning may lead to large enhancements above the uniform background burning rate, since turbulent dissipation gives rise to temperature fluctuations, and in general the nuclear burning rates are highly sensitive to temperature. We derive results for the turbulent enhancement of the nuclear burning rate under the influence of strong turbulence in the distributed burning regime in homogeneous isotropic turbulence, using probability distribution function (PDF) methods. We demonstrate that the turbulent enhancement obeys a universal scaling law in the limit of weak turbulence. We further demonstrate that, for a wide range of key nuclear reactions, such as C $^{12}$ (O $^{16}$ , $α$ )Mg $^{24}$ and triple- $α$ , even relatively modest temperature fluctuations, of the order ten percent, can lead to enhancements of 1 - 3 orders of magnitude in the turbulent nuclear burning rate. We verify the predicted turbulent enhancement directly against numerical simulations, and find very good agreement. We also present an estimation for the onset of turbulent detonation initiation, and discuss implications of our results for the modeling of stellar transients.
Comments:
Submitted, comments welcome
Subjects:
Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th); Fluid Dynamics (physics.flu-dyn)
arXiv:
2002.01937 [pdf]
PRL(2023)·3 citations
09
[Submitted on 5 Feb 2020] (cross-list from nucl-ex)
Evolution of the N=20 and 28 Shell Gaps and 2-particle-2-hole states in the FSU Interaction
R. S. Lubna · K. Kravvaris · S. L. Tabor. Vandana Tripathi · E. Rubino · A. Volya
The FSU $s p s df p$ cross-shell interaction for the shell model was successfully fitted to a wide range of mostly intruder negative parity states of the $s d$ shell nuclei. This paper reports the application of the FSU interaction to systematically trace out the relative positions of the effective single-particle energies of the $0 f_{7/2}$ and $1 p_{3/2}$ orbitals, the evolution from normally ordered low-lying states to the "Island of Inversion" (IoI), and the behavior of a wide range of excited states with a $0 f_{7/2}$ proton and neutron coupled to maximum spin of $7ℏ$ . Above a proton number of about 13 the $0 f_{7/2}$ orbital lies below that of $1 p_{3/2}$ , which is considered normal ordering, but systematically at $Z = 10$ to $12$ the orbitals cross. The calculations reproduce well the 2p2h - 0p0h inversion in the configurations of nuclei inside the IoI, they reproduce the absolute binding energies and the transition to normal ordering as the proton number approaches that of the neutrons. The important role of $1 p_{3/2}$ neutron pairs in the IoI is also demonstrated. The calculations account well for the energies of the fully aligned states with 0, 1, or 2 individual $s d$ nucleon aligned in spin with the aligned $π 0 f_{7/2}$ - $ν 0 f_{7/2}$ pair and reproduce well their systematic variation with $A$ and number of aligned $s d$ nucleons. The results presented in this paper give hope for the predictive power of the FSU interaction for more exotic nuclei to be explored in near future.
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2002.01991 [pdf]
PRResearch(2020)·49 citations
10
[Submitted on 5 Feb 2020] (cross-list from quant-ph)
Fixed-Point Quantum Circuits for Quantum Field Theories
Natalie Klco🇺🇸 · Martin J. Savage🇺🇸
Renormalization group ideas and effective operators are used to efficiently determine localized unitaries for preparing the ground states of non-interacting scalar field theories on digital quantum devices. With these methods, classically computed ground states in a small spatial volume can be used to determine operators for preparing the ground state in a beyond-classical quantum register, even for interacting scalar field theories. Due to the exponential decay of correlation functions and the double exponential suppression of digitization artifacts, the derived quantum circuits are expected to be relevant already for near-term quantum devices.
Comments:
9 pages, 3 figures
Subjects:
Quantum Physics (quant-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2002.02018 [pdf]
PRA(2020)·34 citations
11
[Submitted on 6 Feb 2020] (cross-list from physics.atom-ph)
Skyrme-type nuclear interaction as a tool for calculating the finite nuclear size correction to atomic energy levels and the bound-electron $g$ factor
Igor A. Valuev🇩🇪 · Zoltán Harman🇩🇪 · Christoph H. Keitel🇩🇪 · Natalia S. Oreshkina (Max-Planck-Institut für Kernphysik)🇩🇪
A state-of-the-art approach for calculating the finite nuclear size correction to atomic energy levels and the bound-electron $g$ factor is introduced and demonstrated for a series of highly charged hydrogen-like ions. Firstly, self-consistent mean-field calculations based on the Skyrme-type nuclear interaction are employed in order to produce a realistic nuclear proton distribution. In the second step, the obtained nuclear charge density is used to construct the potential of an extended nucleus, and the Dirac equation is solved numerically. The ambiguity in the choice of a Skyrme parametrization is supressed by fine-tuning of only one parameter of the Skyrme force in order to accurately reproduce the experimental values of nuclear radii in each particular case. The homogeneously charged sphere approximation, the two-parameter Fermi distribution and experimental nuclear charge distributions are used for comparison with our approach, and the uncertainties of the presented calculations are estimated. In addition, suppression of the finite nuclear size effect for the specific differences of $g$ factors is demonstrated.
Comments:
8 pages, 1 figure, 4 tables
Subjects:
Atomic Physics (physics.atom-ph); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2002.02227 [pdf]
PRA(2020)·19 citations
12
[Submitted on 6 Feb 2020] (cross-list from hep-ph)
JIMWLK Evolution, Lindblad Equation and Quantum-Classical Correspondence
Ming Li🇺🇸 · Alex Kovner🇺🇸
In the Color Glass Condensate(CGC) effective theory, the physics of valence gluons with large longitudinal momentum is reflected in the distribution of color charges in the transverse plane. Averaging over the valence degrees of freedom is effected by integrating over classical color charges with some quasi probability weight functional $W [j]$ whose evolution with rapidity is governed by the JIMWLK equation. In this paper, we reformulate this setup in terms of effective quantum field theory on valence Hilbert space governed by the reduced density matrix $ρ^$ for hard gluons, which is obtained after properly integrating out the soft gluon "environment". We show that the evolution of this density matrix with rapidity in the dense and dilute limits has the form of Lindblad equation. The quasi probability distribution (weight) functional $W$ is directly related to the reduced density matrix $ρ^$ through the generalization of the Wigner-Weyl quantum-classical correspondence, which reformulates quantum dynamics on Hilbert space in terms of classical dynamics on the phase space. In the present case the phase space is non Abelian and is spanned by the components of transverse color charge density $j$ . The same correspondence maps the Lindblad equation for $ρ^$ into the JIMWLK evolution equation for $W$ .
Comments:
48 pages, 1 figure, revised version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2002.02282 [pdf]
JHEP(2020)·18 citations
13
[Submitted on 6 Feb 2020] (cross-list from hep-ph)
How does the $S_{11}$ $N^{*} (890)$ state emerge from a naive $K$ matrix fit?
Yao Ma🇨🇳 · Wen-Qi Niu🇨🇳 · Yu-Fei Wang🇩🇪 · Han-Qing Zheng🇨🇳
We give a pedagogical analysis on $K$ matrix models describing the $π N$ scattering amplitude, in $S_{11}$ channel at low energies. We show how the correct use of analyticity in the $s$ channel and crossing symmetry in $t$ and $u$ channels leads to a much improved analytic behavior in the negative $s$ region, in agreement with the prediction from chiral perturbation amplitudes in its validity region. The analysis leads again to the conclusion that a genuine $N^{*} (890)$ resonance exists.
Comments:
9pages, 7 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2002.02351 [pdf]
Commun.Theor.Phys.(2020)·9 citations

Affiliations

first authorsco-authorsvia INSPIRE