Nuclear Theory·nucl-th

Friday·December 7, 2018

10 papers—8 primary·2 cross-listed

01
[Submitted on 5 Dec 2018]
The effect of the Landau--Zener transitions on nuclear fission dynamics
V.M.Kolomietz · S.V.Radionov
In the paper, it is studied the influence of Landau-Zener transitions between nuclear many-body states on the dissipative properties of nuclear large--amplitude collective motion. Within the cranking-like approach, we describe the time evolution of a nuclear many-body system as the self-consistent motion in a space of intrinsic excitations and in a space of a single collective (deformation) parameter. By that we measure how the spectral statistics of the nuclear energy levels affects the fission rate at quite large initial temperatures of heavy nuclei.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1812.02187 [pdf]
0 citations
02
[Submitted on 5 Dec 2018]
On generation of the Bargmann-Moshinsky basis of SU(3) group
S. Vinitsky🇷🇺 · C. Burdik🇷🇺 · A. Gusev🇷🇺 · A. Deveikis🇱🇹 · A. Gozdz🇵🇱 · A. Pedrak🇵🇱 · P.M. Krassovitskiy🇷🇺
An efficient procedure of orthonormalisation of the Bargmann-Moshinsky (BM) basis is examined using analytical formulas of the overlap integrals of the BM basis. Calculations of components of the quadrupole operator between the both BM and the orthonormalised bases needed for construction of the nuclear models are tested. The proposed procedure is also implemented as the Fortran program.
Comments:
13 pages, submitted to Journal of Physics: Conference Series
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1812.02270 [pdf]
J.Phys.Conf.Ser.(2019)·2 citations
03
[Submitted on 6 Dec 2018]
Transverse Takahashi Identities and Their Implications for Gauge Independent Dynamical Chiral Symmetry Breaking
L. Albino🇲🇽 · A. Bashir🇲🇽 · L.X. Gutiérrez Guerrero🇲🇽 · B. El Bennich🇧🇷 · E. Rojas🇨🇴
In this article, we employ transverse Takahashi identities to impose valuable non-perturbative constraints on the transverse part of the fermion-photon vertex in terms of new form factors, the so called $Y_{i}$ functions. We show that the implementation of these identities is crucial in ensuring the correct local gauge transformation of the fermion propagator and its multiplicative renormalizability. Our construction incorporates the correct symmetry properties of the $Y_{i}$ under charge conjugation operation as well as their well-known one-loop expansion in the asymptotic configuration of incoming and outgoing momenta. Furthermore, we make an explicit analysis of various existing constructions of this vertex against the demands of transverse Takahashi identities and the previously established key features of quantum electrodynamics, such as gauge invariance of the critical coupling above which chiral symmetry is dynamically broken. We construct a simple example in its quenched version and compute the mass function as we vary the coupling strength and also calculate the corresponding anomalous dimensions $γ_{m}$ . There is an excellent fit to the Miransky scalling law and we find $γ_{m} = 1$ rather naturally in accordance with some earlier results in literature, using arguments based on Cornwall-Jackiw-Tomboulis effective potential technique. Moreover, we numerically confirm the gauge invariance of this critical coupling.
Comments:
16 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1812.02280 [pdf]
PRD(2019)·48 citations
04
[Submitted on 6 Dec 2018]
Do deviations of neutron scattering widths distribution from the Porter-Thomas law indicate on failure of the Random Matrix theory?
Oleg V. Zhirov🇷🇺
Deviations of neutron scattering width distributions from the Porter-Thomas law due to resonances overlapping are calculated in the extended framework of the random matrix approach.
Comments:
12 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1812.02485 [pdf]
0 citations
05
[Submitted on 6 Dec 2018]
Parton energy loss effect on Z+jet production in high-energy nuclear collisions
Shan-Liang Zhang🇨🇳 · Tan Luo🇨🇳 · Xin-Nian Wang🇨🇳 · Ben-Wei Zhang🇨🇳
We give a report of medium modification of Z+jet correlations in Pb+Pb collisions at the Large Hadron Collider using Sherpa to generate initial Z+jet at next-leading-order matrix element matched parton shower, and the Linear Boltzmann Transport Model for jet propagation in the expanding quark-gluon-plasma. Our numerical calculations show excellent agreement with all available observables of Z+jet simultaneously in both proton + proton and Pb+Pb collisions. Our results can well explain the shift of momentum asymmetry $x_{j Z} = p_{T}^{j e t} / p_{T}^{Z}$ as well as its mean values, the suppression of the jet yields per Z trigger $R_{j Z}$ and the modification of azimuthal angle correlation $Δ ϕ_{j Z}$ . We also demonstrate that it is the energy loss effect on multi-jets from high-order corrections that leads to the suppression of the Z+jet correlation at small azimuthal angle difference $Δ ϕ_{j Z}$ and at small $x_{j Z}$ . The jet shape reflecting transverse momentum distribution inside the jet is also calculated, which indicates that large fraction of jet energy is carried away from the jet axis in Pb+Pb collisions.
Comments:
4 pages, 4 figures, talk at Hard Probes 2018 conference
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1812.02508 [pdf]
PoS(2018)·0 citations
06
[Submitted on 2 Dec 2018]
Structure of hot strange quark stars: an NJL model approach at finite temperature
G. H. Bordbar🇮🇷 · R. Hosseini🇮🇷 · F. Kayanikhoo🇮🇷 · A. Poostforush🇮🇷
In this paper, we investigated the thermodynamic properties of strange quark matter using Nambu-Jona-Lasinio (NJL) model at finite temperatures where we considered the dynamical mass as the effective interaction between quarks. By considering the pressure of strange quark matter (SQM) at finite temperatures, we showed that the equation of state of this system gets stiffer by increasing temperature. In addition, we investigated the energy conditions and stability of the equation of state and showed that the equation of state of SQM satisfy the conditions of stability. Finally, we computed the structure properties of hot strange quark stars (SQS) including the gravitational mass, radius, Schwarzschild radius, average density, compactness and gravitational redshift. Our calculations showed that in this model, the maximum mass and radius of SQS increase by increasing temperature. Furthermore it was shown that the average density of SQS is greater than the normal nuclear density, and it is an increasing function of temperature. We also discussed the temperature dependence of the maximum gravitational mass calculated from different methods.
Comments:
19 pages, 9 figures, 2 tables Astrophysics (2018) accepted
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
1812.02577 [pdf]
Astrophysics(2019)·3 citations
07
[Submitted on 6 Dec 2018]
Finite Element Method for Solving the Collective Nuclear Model with Tetrahedral Symmetry
A.A. Gusev · S.I. Vinitsky · O.Chuluunbaatar · A. Gozdz · A. Dobrowolski · K. Mazurek · P.M. Krassovitskiy
We apply a new calculation scheme of a finite element method (FEM) for solving an elliptic boundary-value problem describing a quadrupole vibration collective nuclear model with tetrahedral symmetry. We use of shape functions constructed with interpolation Lagrange polynomials on a triangle finite element grid and compare the FEM results with obtained early by a finite difference method.
Comments:
6 pages, 3 figures, 1 table
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1812.02665 [pdf]
Acta Phys.Polon.Supp.(2019)·1 citation
08
[Submitted on 6 Dec 2018]
Defining the Proton Radius: a Unified Treatment
Gerald A. Miller🇺🇸
Background: There is significant current interest in knowing the value of the proton radius and also its proper definition. Purpose: Combine the disparate literatures of hydrogen spectroscopy and diverse modern parton distributions to show that the quantity $r_{p}^{2} \equiv - 6 G_{E}^{'} (0)$ is the relativistically proper definition that originates from the separate bodies of work. Methods: Use perturbation theory, light-front dynamics and elementary techniques to find relativistically correct definitions of the proton radius and charge density. Results: It is found that the very same proton radius is accessed by measurements of hydrogen spectroscopy and elastic lepton scattering. The derivation of the mean-square radius as a moment of a spherically symmetric three-dimensional density is shown to be incorrect. A relativistically-correct, two-dimensional charge density is related to the diverse modern literature of various parton distributions. Relativistically invariant moments thereof are derived in a new moment expansion, the RME.
Comments:
18 pages, two figures. Replacement involves improving the language and adding a reference
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Atomic Physics (physics.atom-ph)
arXiv:
1812.02714 [pdf]
PRC(2019)·138 citations
09
[Submitted on 30 Nov 2018] (cross-list from physics.plasm-ph)
Ionization potential depression and Pauli blocking in degenerate plasmas at extreme densities
Gerd Röpke · David Blaschke · Tilo Döppner · Chengliang Lin · Wolf-Dietrich Kraeft · Ronald Redmer · Heidi Reinholz
New facilities explore warm dense matter (WDM) at extreme conditions where the densities are very high (e.g., carbon up to density of 50 g cm $^{- 3}$ ) so that electrons are degenerate even at 100 eV temperature. Whereas in the non-degenerate region correlation effects such as Debye screening and its improvements are relevant for the ionization potential depression (IPD), new effects have to be considered in degenerate plasmas. In addition to the Fock shift of the self-energies, the bound-state Pauli blocking becomes important with increasing density. Taking these degeneracy effects into account leads to a reduction of the ionization potential and to a higher degree of ionization. Standard approaches to IPD such as Stewart-Pyatt and widely used opacity tables (e.g., OPAL) do not contain Pauli blocking effects for bound states so that they fail to explain experiments with WDM in the high density region. As example, results for the ionization degree of carbon plasmas are presented.
Comments:
15 pages, 3 figures
Subjects:
Plasma Physics (physics.plasm-ph); Nuclear Theory (nucl-th)
arXiv:
1811.12912 [pdf]
PRE(2019)·8 citations
10
[Submitted on 5 Dec 2018] (cross-list from hep-ph)
Quarkonium production in heavy ion collisions: coupled Boltzmann transport equations
Xiaojun Yao🇺🇸 · Weiyao Ke🇺🇸 · Yingru Xu🇺🇸 · Steffen Bass🇺🇸 · Berndt Müller🇺🇸
By coupling the Boltzmann transport equations of both quarkonium and open heavy quarks, we investigate their dynamical evolution inside the quark-gluon plasma and study quarkonium production in heavy ion collisions. The Boltzmann transport equation of quarkonium is derived from the open quantum system formalism and effective field theory of QCD by assuming quarkonium interacts weakly with the plasma. The dissociation and recombination terms in the Boltzmann equation are calculated in potential nonrelativistic QCD. It is shown that the combination of quarkonium dissociation, recombination, open heavy quark diffusion and energy loss can drive the system of quarkonium and open heavy quarks to detailed balance and kinetic thermalization. By solving the transport equations with initial momenta of quarkonia and heavy quarks sampled from PYTHIA and a hydrodynamic medium, we can calculate the nuclear modification factors of bottomonium and describe the data at both RHIC and LHC energies. The azimuthal angular anisotropy coefficient $v_{2}$ of $Υ$ (1S) in 5.02 TeV peripheral Pb-Pb collisions is also predicted.
Comments:
5 pages, 1 figure, contribution to the proceedings of Hard Probes 2018: International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1812.02238 [pdf]
PoS(2018)·7 citations

Affiliations

first authorsco-authorsvia INSPIRE