Nuclear Theory·nucl-th

Wednesday·June 29, 2016

13 papers—10 primary·3 cross-listed

01
[Submitted on 28 Jun 2016]
Microscopic derivation of the Bohr-Mottelson collective Hamiltonian and its application to quadrupole shape dynamics
Kenichi Matsuyanagi · Masayuki Matsuo · Takashi Nakatsukasa · Kenichi Yoshida · Nobuo Hinohara · Koichi Sato
We discuss the nature of the low-frequency quadrupole vibrations from small-amplitude to large-amplitude regimes. We consider full five-dimensional quadrupole dynamics including three-dimensional rotations restoring the broken symmetries as well as axially symmetric and asymmetric shape fluctuations. Assuming that the time-evolution of the self-consistent mean field is determined by five pairs of collective coordinates and collective momenta, we microscopically derive the collective Hamiltonian of Bohr and Mottelson, which describes low-frequency quadrupole dynamics. We show that the five-dimensional collective Schrödinger equation is capable of describing large-amplitude quadrupole shape dynamics seen as shape coexistence/mixing phenomena. We summarize the modern concepts of microscopic theory of large-amplitude collective motion, which is underlying the microscopic derivation of the Bohr-Mottelson collective Hamiltonian.
Comments:
62 pages, 6 figures, Review article, Invited Comment in Focus Issue of Physica Scripta to celebrate the 40-year anniversary of the 1975 Nobel Prize to A. Bohr, B. R. Mottelson and L. J. Rainwater (Phys. Scr. 91 (2016) 063014). arXiv admin note: text overlap with arXiv:1606.04717
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1606.08547 [pdf]
Phys.Scripta(2016)·24 citations
02
[Submitted on 28 Jun 2016]
Thermal Relaxation, Electrical Conductivity and Charge Diffusion in a Hot QCD Medium
Sukanya Mitra🇮🇳 · Vinod Chandra🇮🇳
The response of electromagnetic (EM) fields that are produced in non-central heavy-ion collisions to electromagnetically charged quark gluon plasma can be understood in terms of charge transport and charge diffusion in the hot QCD medium. This article presents a perspective on these processes by investigating the temperature behavior of the related transport coefficients, {\it viz.} electrical conductivity and the charge diffusion coefficients along with charge susceptibility. In the process of estimating them, thermal relaxation times for quarks and gluons have been determined first. These transport coefficients have been studied by solving the relativistic transport equation in the Chapman-Enskog method. For the analysis, $2 \to 2$ , quark-quark, quark-gluon and gluon-gluon scattering processes are taken into account along with an effective description of hot QCD Equations of state (EOSs) in terms of temperature dependent effective fugacities of quasi-quarks (anti-quarks) and quasi-gluons. Both improved perturbative hot QCD EOSs at high temperature and a lattice QCD EOS are included for the analysis. The hot QCD medium effects entering through the quasi-particle momentum distributions along with an effective coupling, are seen to have significant impact on the temperature behavior of these transport parameters along with the thermal relaxation times for the quasi-gluons and quasi-quarks
Comments:
v2: accepted in Phys. Rev. D
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1606.08556 [pdf]
PRD(2016)·50 citations
03
[Submitted on 28 Jun 2016]
Pseudospin symmetry in nuclear structure and its supersymmetric representation
Haozhao Liang🇯🇵
The quasi-degeneracy between the single-particle states $(n, l, j = l + 1/2)$ and $(n - 1, l + 2, j = l + 3/2)$ indicates a special and hidden symmetry in atomic nuclei---the so-called pseudospin symmetry (PSS)---which is an important concept in both spherical and deformed nuclei. A number of phenomena in nuclear structure have been successfully interpreted directly or implicitly by this symmetry, including nuclear superdeformed configurations, identical bands, quantized alignment, pseudospin partner bands, and so on. Since the PSS was recognized as a relativistic symmetry in 1990s, there have been comprehensive efforts to understand its properties in various systems and potentials. In this Review, we mainly focus on the latest progress on the supersymmetric (SUSY) representation of PSS, and one of the key targets is to understand its symmetry-breaking mechanism in realistic nuclei in a quantitative and perturbative way. The SUSY quantum mechanics and its applications to the SU(2) and U(3) symmetries of the Dirac Hamiltonian are discussed in detail. It is shown that the origin of PSS and its symmetry-breaking mechanism, which are deeply hidden in the origin Hamiltonian, can be traced by its SUSY partner Hamiltonian. Essential open questions, such as the SUSY representation of PSS in the deformed system, are pointed out.
Comments:
21 pages, 16 figures; Focus issue to celebrate the 40 year anniversary of the 1975 Nobel Prize to Aage Niels Bohr, Ben Roy Mottelson and Leo James Rainwater in Physica Scripta
Subjects:
Nuclear Theory (nucl-th); Mathematical Physics (math-ph); math.MP (math.MP); Quantum Physics (quant-ph)
arXiv:
1606.08570 [pdf]
Phys.Scripta(2016)·5 citations
04
[Submitted on 28 Jun 2016]
Application of Origen2.1 in the decay photon spectrum calculation of spallation products
Shuang Hong · Yong-Wei Yang · Hu-Shan Xu · Hai-Yan Meng · Lu Zhang · Zhao-Qing Liu · Yu-Cui Gao · Kang Chen
Origen2.1 is a widely used computer code for calculating the burnup, decay, and processing of radioactive materials. However, the nuclide library of Origen2.1 is used for existing reactors like pressurized water reactor, to calculate the photon spectrum released by the decay of spallation products, we have made specific libraries for the ADS tungsten spallation target, based on the results given by a Monte Carlo code: FLUKA. All the data used to make the Origen2.1 libraries is obtained from Nuclear structure & decay Data (NuDat2.6). The accumulated activity of spallation products and the contribution of nuclides to photon emission are given in this paper.
Comments:
To be published in Chinese Physics C
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1606.08594 [pdf]
CPC(2016)·1 citation
05
[Submitted on 28 Jun 2016]
Sloppy nuclear energy density functionals: effective model reduction
Tamara Niksic · Dario Vretenar
Concepts from information geometry are used to analyse parameter sensitivity for a nuclear energy density functional, representative of a class of semi-empirical functionals that start from a microscopically motivated ansatz for the density dependence of the energy of a system of protons and neutrons. It is shown that such functionals are sloppy, characterized by an exponential range of sensitivity to parameter variations. Responsive to only a few stiff parameter combinations, they exhibit an exponential decrease of sensitivity to variations of the remaining soft parameters. By interpreting the space of model predictions as a manifold embedded in the data space, with the parameters of the functional as coordinates on the manifold, it is also shown that the exponential distribution of model manifold widths corresponds to the distribution of parameter sensitivity. Using the Manifold Boundary Approximation Method, we illustrate how to systematically construct effective nuclear density functionals of successively lower dimension in parameter space until sloppiness is eventually eliminated and the resulting functional contains only stiff combinations of parameters.
Comments:
11 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1606.08617 [pdf]
PRC(2016)·23 citations
06
[Submitted on 28 Jun 2016]
Correlations in neutrino-nucleus scattering
Tom Van Cuyck🇧🇪 · Vishvas Pandey🇧🇪 · Natalie Jachowicz🇧🇪 · Raul González-Jiménez🇧🇪 · Marco Martini🇧🇪 · Jan Ryckebusch🇧🇪 · Nils Van Dessel🇧🇪
We present a detailed study of charged-current quasielastic neutrino-nucleus scattering and of the influence of correlations on one- and two-nucleon knockout processes. The quasielastic neutrino-nucleus scattering cross sections, including the influence of long-range correlations, are evaluated within a continuum random phase approximation approach. The short-range correlation formalism is implemented in the impulse approximation by shifting the complexity induced by the correlations from the wave functions to the operators. The model is validated by confronting $(e, e^{'})$ cross-section predictions with electron scattering data in the kinematic region where the quasielastic channel is expected to dominate. Further, the $^{12}$ C $(ν, μ^{-})$ experiments are studied. Double differential cross sections relevant for neutrino-oscillation $^{12}$ C $(ν, μ^{-})$ cross sections, accounting for long- and short-range correlations in the one-particle emission channel and short-range correlations in the two-particle two-hole channel, are presented for kinematics relevant for recent neutrino-nucleus scattering measurements.
Comments:
10 pages, 4 figures. Contribution to the proceedings of the 17th International Workshop on Neutrino Factories and Future Neutrino Beam Facilities (NUFACT-2015)
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1606.08636 [pdf]
0 citations
07
[Submitted on 28 Jun 2016]
The fusion dynamics for a positive Q-value system: $^{27}$ Al+ $^{45}$ Sc using SEDF and role of spin-orbit interaction potential
Dalip Singh Verma · Atul Choudhary
The fusion dynamics for a positive Q-value systems: $^{27}$ Al+ $^{45}$ Sc, at near and deep sub-barrier energies has been investigated using the proximity potentials of Skyrme energy density formalism in semi classical extended Thomas Fermi approach for arbitrarily chosen Skyrme forces: SLy4, SIV, SGII and Proximity77 of Blocki and co-workers. The calculated fusion excitation functions for the proximity potentials obtained for Skyrme forces mentioned above and for the Proximity77 have been compared with experimental data. The proximity potential for Skyrme force SIV is found to be the best and is used in the calculations of the quantities like logarithmic derivative, barriers distributions and $S$ -factor. Further, the role of spin-orbit interaction potential in the fusion dynamics of this system has been investigated.
Comments:
12 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1606.08637 [pdf]
0 citations
08
[Submitted on 27 Jun 2016]
$D^{*}$ $Ξ N$ bound state in strange three-body systems
H. Garcilazo🇲🇽 · A. Valcarce🇪🇸
The recent update of the strangeness $- 2$ ESC08c Nijmegen potential incorporating the NAGARA and KISO events predicts a $Ξ N$ bound state, $D^{*}$ , in the $^{3} S_{1} (I = 1)$ channel. We study if the existence of this two-body bound state could give rise to stable three-body systems. For this purpose we solve the bound state problem of three-body systems where the $Ξ N$ state is merged with $N$ 's, $Λ$ 's, $Σ^{'} s$ or $Ξ$ 's, making use of the most recent updates of the two-body ESC08c Nijmegen potentials. We found that there appear stable states in the $Ξ N N$ and $ΞΞ N$ systems, the $ΞΛ N$ and $ΞΣ N$ systems being unbound.
Comments:
16 pages, 5 figures. arXiv admin note: substantial text overlap with arXiv:1605.04108
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1606.08767 [pdf]
PRC(2016)·8 citations
09
[Submitted on 28 Jun 2016]
Novel applications of the dispersive optical model
W. H. Dickhoff · R. J. Charity · M. H. Mahzoon
A review of recent developments of the dispersive optical model (DOM) is presented. Starting from the original work of Mahaux and Sartor, several necessary steps are developed and illustrated which increase the scope of the DOM allowing its interpretation as generating an experimentally constrained functional form of the nucleon self-energy. The method could therefore be renamed as the dispersive self-energy method. The aforementioned steps include the introduction of simultaneous fits of data for chains of isotopes or isotones allowing a data-driven extrapolation for the prediction of scattering cross sections and level properties in the direction of the respective drip lines. In addition, the energy domain for data was enlarged to include results up to 200 MeV where available. An important application of this work was implemented by employing these DOM potentials to the analysis of the (\textit{d,p}) transfer reaction using the adiabatic distorted wave approximation (ADWA). We review the fully non-local DOM potential fitted to $^{40}$ Ca where elastic-scattering data, level information, particle number, charge density and high-momentum-removal $(e, e^{'} p)$ cross sections obtained at Jefferson Lab were included in the analysis. An important consequence of this new analysis is the finding that the spectroscopic factor for the removal of valence protons in this nucleus comes out larger by about 0.15 than the results obtained from the NIKHEF analysis of their $(e, e^{'} p)$ data. Another important consequence of this analysis is that it can shed light on the relative importance of two-body and three-body interactions as far as their contribution to the energy of the ground state is concerned through application of the energy sum rule.
Comments:
Invited Topical Review for Journal of Physics G: Nuclear and Particle Physics containing 64 pages and 25 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1606.08822 [pdf]
J.Phys.G(2017)·51 citations
10
[Submitted on 28 Jun 2016]
The Nuclear Symmetry Energy
M. Baldo🇮🇹 · G. F. Burgio (INFN Sezione di Catania, Italy)🇮🇹
The nuclear symmetry energy characterizes the variation of the binding energy as the neutron to proton ratio of a nuclear system is varied. This is one of the most important features of nuclear physics in general, since it is just related to the two component nature of the nuclear systems. As such it is one of the most relevant physical parameters that affect the physics of many phenomena and nuclear processes. This review paper presents a survey of the role and relevance of the nuclear symmetry energy in different fields of research and of the accuracy of its determination from the phenomenology and from the microscopic many-body theory. In recent years, a great interest was devoted not only to the Nuclear Matter symmetry energy at saturation density but also to its whole density dependence, which is an essential ingredient for our understanding of many phenomena. We analyze the nuclear symmetry energy in different realms of nuclear physics and astrophysics. In particular we consider the nuclear symmetry energy in relation to nuclear structure, astrophysics of Neutron Stars and supernovae, and heavy ion collision experiments, trying to elucidate the connections of these different fields on the basis of the symmetry energy peculiarities. The interplay between experimental and observational data and theoretical developments is stressed. The expected future developments and improvements are schematically addressed, together with most demanded experimental and theoretical advances for the next few years.
Comments:
71 pages, 33 figures, accepted for publication by Progress in Particle and Nuclear Physics. arXiv admin note: text overlap with arXiv:1310.2896, arXiv:1205.2585, arXiv:nucl-ex/0610013, arXiv:1407.7625, arXiv:nucl-ex/0310024, arXiv:1101.3648, arXiv:1406.4546, arXiv:1309.5153, arXiv:1401.2074, arXiv:1210.3402, arXiv:1506.04687, arXiv:astro-ph/0407529 by other authors
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
1606.08838 [pdf]
PPNP(2016)·297 citations

Affiliations

first authorsco-authorsvia INSPIRE