skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Quantitative properties of clustering within modern microscopic nuclear models

Abstract

A method for studying cluster spectroscopic properties of nuclear fragmentation, such as spectroscopic amplitudes, cluster form factors, and spectroscopic factors, is developed on the basis of modern precision nuclear models that take into account the mixing of large-scale shell-model configurations. Alpha-cluster channels are considered as an example. A mathematical proof of the need for taking into account the channel-wave-function renormalization generated by exchange terms of the antisymmetrization operator (Fliessbach effect) is given. Examples where this effect is confirmed by a high quality of the description of experimental data are presented. By and large, the method in question extends substantially the possibilities for studying clustering phenomena in nuclei and for improving the quality of their description.

Authors:
 [1];  [2]
  1. Florida State University (United States)
  2. Moscow State University, Skobelstsyn Institute of Nuclear Physics (Russian Federation)
Publication Date:
OSTI Identifier:
22612613
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Atomic Nuclei; Journal Volume: 79; Journal Issue: 5; Other Information: Copyright (c) 2016 Pleiades Publishing, Ltd.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ACCURACY; CONFIGURATION; EXPERIMENTAL DATA; FORM FACTORS; NUCLEAR FRAGMENTATION; NUCLEI; RENORMALIZATION; SHELL MODELS; SPECTROSCOPIC FACTORS; WAVE FUNCTIONS

Citation Formats

Volya, A., and Tchuvil’sky, Yu. M., E-mail: tchuvl@nucl-th.sinp.msu.ru. Quantitative properties of clustering within modern microscopic nuclear models. United States: N. p., 2016. Web. doi:10.1134/S1063778816040220.
Volya, A., & Tchuvil’sky, Yu. M., E-mail: tchuvl@nucl-th.sinp.msu.ru. Quantitative properties of clustering within modern microscopic nuclear models. United States. doi:10.1134/S1063778816040220.
Volya, A., and Tchuvil’sky, Yu. M., E-mail: tchuvl@nucl-th.sinp.msu.ru. 2016. "Quantitative properties of clustering within modern microscopic nuclear models". United States. doi:10.1134/S1063778816040220.
@article{osti_22612613,
title = {Quantitative properties of clustering within modern microscopic nuclear models},
author = {Volya, A. and Tchuvil’sky, Yu. M., E-mail: tchuvl@nucl-th.sinp.msu.ru},
abstractNote = {A method for studying cluster spectroscopic properties of nuclear fragmentation, such as spectroscopic amplitudes, cluster form factors, and spectroscopic factors, is developed on the basis of modern precision nuclear models that take into account the mixing of large-scale shell-model configurations. Alpha-cluster channels are considered as an example. A mathematical proof of the need for taking into account the channel-wave-function renormalization generated by exchange terms of the antisymmetrization operator (Fliessbach effect) is given. Examples where this effect is confirmed by a high quality of the description of experimental data are presented. By and large, the method in question extends substantially the possibilities for studying clustering phenomena in nuclei and for improving the quality of their description.},
doi = {10.1134/S1063778816040220},
journal = {Physics of Atomic Nuclei},
number = 5,
volume = 79,
place = {United States},
year = 2016,
month = 9
}
  • Cited by 6
  • Open Quantum System (OQS) description of a many-body system involves interaction of Shell Model (SM) states through the particle continuum. In realistic nuclear applications, this interaction may lead to collective phenomena in the ensemble of SM states. We claim that the nuclear clustering is an emergent, near-threshold phenomenon, which cannot be elucidated within the Closed Quantum System (CQS) framework. We approach this problem by investigating the near-threshold behavior of Exceptional Points (EPs) in the realistic Continuum Shell Model (CSM). The consequences for the alpha-clustering phenomenon are discussed.
  • Upper limits on the angular correlation function, w(theta), of gamma-ray bursts are obtained which constrain the sources to be very nearby or very distant. The angular clustering properties of the sources in two recent gamma-ray burst catalogs (Golenetskii et al., 1986 and Atteia et al., 1987) have been derived by determining their two-point w(theta) values, and the correlations of both data sets are consistent with w(theta) = 0. It is shown that if the spatial correlation of gamma-ray bursts resembles that of galaxies or galactic clusters, present gamma-ray burst catalogs must be complete to distances in excess of 100 Mpc,more » while if gamma-ray bursts are associated with a Galactic disk population, then the upper limits on w(theta) constrain the sampling depth to less than two disk scale heights. 50 refs.« less
  • We provide a generic but physically clear discussion of the clustering properties of dark energy models. We explicitly show that in quintessence-type models the dark energy fluctuations, on scales smaller than the Hubble radius, are of the order of the perturbations to the Newtonian gravitational potential, hence necessarily small on cosmological scales. Moreover, comparable fluctuations are associated with different gauge choices. We also demonstrate that the often used homogeneous approximation is unrealistic, and that the so-called dark energy mutation is a trivial artifact of an effective, single fluid description. Finally, we discuss the particular case where the dark energy fluidmore » is nonminimally coupled to dark matter.« less
  • New developments have been brought to our energy-, spin-, and parity-dependent nuclear level densities based on the microscopic combinatorial model. As in our previous study, a detailed calculation of the intrinsic state density and of the rotational enhancement factor is included, but this time the vibrational contributions explicitly take the phonon excitations into account. The present model predicts the experimental s- and p-wave neutron resonance spacings with a degree of accuracy comparable to that of the best global models available. It is also shown that the model gives a reliable extrapolation at low energies where experimental data on the cumulativemore » number of levels can be extracted. The predictions are also in good agreement with the experimental data extracted from the analysis of particle-{gamma} coincidence in the ({sup 3}He, {alpha}{gamma}) and ({sup 3}He, {sup 3}He{sup '}{gamma}) reactions. Total as well as partial level densities for more than 8500 nuclei are made available in a table format for practical applications. For the nuclei for which experimental s-wave spacings and enough low-lying states exist, renormalization factors are provided to reproduce simultaneously both observables. The same combinatorial method is used to estimate the nuclear level densities at the fission saddle points of actinides and at the shape isomer deformation. Finally, the new nuclear level densities are applied to the calculation of radiative neutron capture cross sections.« less