Nuclear Theory·nucl-th

Wednesday·July 22, 2015

7 papers—3 primary·4 cross-listed

01
[Submitted on 21 Jul 2015]
Bose-Einstein condensates in neutron stars
C.J. Pethick🇩🇰 · Thomas Schaefer🇺🇸 · A. Schwenk🇩🇪
In the two decades since the appearance of the book "Bose-Einstein Condensation" in 1995, there have been a number of developments in our understanding of dense matter. After a brief overview of neutron star structure and the Bose-Einstein condensed phases that have been proposed, we describe selected topics, including neutron and proton pairing gaps, the physics of the inner crust of neutron stars, where a neutron fluid penetrates a lattice of nuclei, meson condensates, and pairing in dense quark matter. Especial emphasis is placed on basic physical effects and on connections to the physics of cold atomic gases.
Comments:
22 pages, 2 figures, to appear in "Universal Themes of Bose-Einstein Condensation", edited by D.W. Snoke, N.P. Proukakis and P.B. Littlewood (Cambridge University Press)
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Quantum Gases (cond-mat.quant-gas); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1507.05839 [pdf]
23 citations
02
[Submitted on 21 Jul 2015]
Correlations between bulk parameters in relativistic and nonrelativistic hadronic mean-field models
B. M. Santos🇧🇷 · M. Dutra🇧🇷 · O. Lourenço🇧🇷 · A. Delfino🇧🇷
In this work, we study the arising of correlations among some isoscalar ( $K_{o}$ , $Q_{o}$ , and $I_{o}$ ) and isovector ( $J$ , $L_{o}$ , $K_{sy m}^{o}$ , $Q_{sy m}^{o}$ , and $I_{sy m}^{o}$ ) bulk parameters in nonrelativistic and relativistic hadronic mean-field models. For the former, we investigate correlations in Skyrme and Gogny parametrizations, as well as in the nonrelativistic (NR) limit of relativistic point-coupling models. We provide analytical correlations among bulk parameters for the NR limit, discussing the conditions in which they are linear ones. Based on a recent study [B. M. Santos et al., Phys. Rev. C 90, 035203 (2014)], we also show that some correlations presented in the NR limit are reproduced for relativistic models presenting cubic and quartic self-interactions in the scalar field $σ$ , mostly studied in this work in the context of the relativistic framework. We also discuss how the crossing points, observed in the density dependence of some bulk parameters, can be seen as a signature of linear correlations between the specific bulk quantity presenting the crossing, and its immediately next order parameter.
Comments:
18 pages, 28 figures
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
1507.05856 [pdf]
PRC(2015)·16 citations
03
[Submitted on 21 Jul 2015]
A simple formula for local burnup based on constant relative reaction rate per nuclei
Cenxi Yuan · Xuming Wang · Shengli Chen
A simple and analytical formula is suggested to solve the problems of the local burnup and the isotope distributions. The present method considers two extreme conditions of neutrons penetrating the fuel rod. Based on these considerations, the formula is obtained to calculate the reaction rates of $^{235}$ U, $^{238}$ U, and $^{239}$ Pu and straightforward the local burnup and the isotope distributions. Starting from an initial burnup level, the parameters of the formula are fitted to the reaction rates given by a Monte Carlo (MC) calculation. Then the present formula independently gives very similar results as the MC calculation from the starting to high burnup level, but takes just a few minutes. The relative reaction rates are found to be almost independent on the radius (except $(n, γ)$ of $^{238}$ U) and the burnup, providing a solid background for the present formula. A more realistic examination is also performed when the fuel rods locate in an assembly. A combination of the present formula and the MC calculation is expected to have a nice balance on the accuracy and the cost on time.
Subjects:
Nuclear Theory (nucl-th); Instrumentation and Detectors (physics.ins-det)
arXiv:
1507.05892 [pdf]
Science and Technology of Nuclear Install…·1 citation
04
[Submitted on 20 Jul 2015] (cross-list from hep-ph)
JUNO and Neutrinoless Double Beta Decay
Shao-Feng Ge🇩🇪 · Werner Rodejohann🇩🇪
We study the impact of the precision determination of oscillation parameters in the JUNO experiment on half-life predictions for neutrinoless double beta decay. We show that the solar neutrino mixing angle can be measured by JUNO with below 1% uncertainty. This implies in particular that the minimal value of the effective mass in the inverted mass ordering will be known essentially without uncertainty. We demonstrate that this reduces the range of half-life predictions in order to test this value by a factor of two. The remaining uncertainty is caused by nuclear matrix elements. This has important consequences for future double beta decay experiments that aim at ruling out the inverted mass ordering or the Majorana nature of neutrinos.
Comments:
11 pages, 7 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1507.05514 [pdf]
PRD(2015)·26 citations
05
[Submitted on 21 Jul 2015] (cross-list from hep-ph)
Survival of charged rho condensation at high temperature and density
Hao Liu🇨🇳 · Lang Yu🇨🇳 · Mei Huang🇨🇳
The charged vector $ρ$ mesons in the presence of external magnetic fields at finite temperature $T$ and chemical potential $μ$ have been investigated in the framework of the Nambu--Jona-Lasinio model. We compute the masses of charged $ρ$ mesons numerically as a function of the magnetic field for different values of temperature and chemical potential. The self-energy of the $ρ$ meson contains the quark-loop contribution, i.e. the leading order contribution in $1/ N_{c}$ expansion. The charged $ρ$ meson mass decreases with the magnetic field and drops to zero at a critical magnetic field $e B_{c}$ , which means that the charged vector meson condensation, i.e. the electromagnetic superconductor can be induced above the critical magnetic field. Surprisingly, it is found that the charged $ρ$ condensation can even survive at high temperature and density. At zero temperature, the critical magnetic field just increases slightly with the chemical potential, which indicates that the charged $ρ$ condensation might occur inside compact stars. At zero density, in the temperature range $0.2 - 0.5 GeV$ , the critical magnetic field for charged $ρ$ condensation is in the range of $0.2 - 0.6 GeV^{2}$ , which indicates that the high temperature electromagnetic superconductor could be created at LHC.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1507.05809 [pdf]
CPC(2016)·21 citations
06
[Submitted on 21 Jul 2015] (cross-list from hep-ph)
Generalised Parton Distributions: A Dyson-Schwinger approach for the pion
C. Mezrag🇫🇷
We compute the pion quark Generalised Parton Distribution H and quark Double Distributions in a coupled Bethe-Salpeter and Dyson-Schwinger approach in terms of quark flavors or isospin states. We use analytic expressions inspired by the numerical resolution of Dyson-Schwinger and Bethe-Salpeter equations. We obtain an analytic expression for the pion Generalised Parton Distribution at a low scale. Our model fulfils most of the required symmetry properties and compares very well to experimental pion form factor or valence parton distribution function experimental data. In addition, we have highlighted limitations of the so-called impulse approximation, which breaks symmetries when computing the valence parton distribution function. Doing so, we introduced new terms which were neglected before. Finally, we also shed light on a specific property of the pion GPD: Polyakov soft pion theorem.
Comments:
8 pages, 3 figures, to appear in the proceedings of the XXIII International Workshop on Deep-Inelastic Scattering and Related Subjects, April 27 - May 1, 2015, Dallas, Texas, USA
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1507.05824 [pdf]
PoS(2015)·0 citations
07
[Submitted on 21 Jul 2015] (cross-list from hep-ph)
The Pentaquark Candidates in the Dynamical Diquark Picture
Richard F. Lebed🇺🇸
Starting with the dynamical picture of the exotic $c c ˉ$ -containing states $X Y Z$ as the confinement-induced hadronization of a rapidly separating pair of a compact diquark and antidiquark, we describe the pentaquark candidates $P_{c}^{+} (4380)$ and $P_{c}^{+} (4450)$ in terms of a confined but rapidly separating color-antitriplet diquark $c u$ and color-triplet "triquark" $c ˉ (u d)$ . This separation explains the relatively small $P_{c}^{+}$ widths, despite these 5-quark systems lying far above both the $J / ψ p$ and $Λ_{c} D ˉ^{(*) 0}$ thresholds. The $P_{c}^{+}$ states are predicted to form isospin doublets with neutral partners $P_{c}^{0}$ .
Comments:
5 pages, 1 pdf figure, pdflatex. Version accepted by Phys. Lett. B
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1507.05867 [pdf]
PLB(2015)·291 citations

Affiliations

first authorsco-authorsvia INSPIRE

Bose-Einstein condensates in neutron stars

Correlations between bulk parameters in relativistic and nonrelativistic hadronic mean-field models

A simple formula for local burnup based on constant relative reaction rate per nuclei

JUNO and Neutrinoless Double Beta Decay

Survival of charged rho condensation at high temperature and density

Generalised Parton Distributions: A Dyson-Schwinger approach for the pion

The Pentaquark Candidates in the Dynamical Diquark Picture

Affiliations