Nuclear Theory·nucl-th

Monday·May 1, 2023

8 papers—2 primary·6 cross-listed

01
[Submitted on 28 Apr 2023]
Gravitational waves from non-radial perturbations in glitching pulsars
Joydev Lahiri🇮🇳 · D. N. Basu🇮🇳
The Rossby mode (r-mode) perturbations in pulsars as a steady gravitational wave (GW) sources have been explored. The time evolution and the intensity of the emitted GWs in terms of the strain tensor amplitude have been estimated with the approximation of slow rotation adopting the equation of state derived using the Skyrme effective interaction with NRAPR parameter set. The core of the neutron star has been considered to be $β$ -equilibrated nuclear matter composed of neutrons, protons, electrons and muons, which is surrounded by a solid crust. Calculations have been made for the critical frequencies, the evolution of frequencies and frequency change rates with time as well as the fiducial viscous and gravitational timescales, across a broad spectrum of pulsar masses. Our findings reveal that the r-mode instability region is associated with rotating young and hot pulsars. Furthermore, it is noteworthy that pulsars with low $L$ value emit gravitational radiation and fall within the r-mode instability region if the primary dissipative mechanism is shear viscosity along the crust-core interface boundary layer. The r-mode perturbation amplitude increases because of GW emissions, in contrast to other non-radial perturbations which transport to infinity the star's angular momentum. Thus the presence of these stellar perturbations implies a non-negative rate of change in transfer of rotational angular momentum. This observation suggests that for a glitching pulsar, the GW emission intensity evolves increasingly with time till the angular frequency diminishes to a value that is below a crucial threshold, after which the compact star ceases to emit radiation.
Comments:
15 pages including 15 figures and 2 tables
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
2304.14644 [pdf]
0 citations
02
[Submitted on 28 Apr 2023]
Finite temperature description of Fermi gases with in-medium effective mass
Mariana Dutra🇫🇷 · Odilon Lourenço🇫🇷 · Jérôme Margueron🇫🇷
We investigate Fermi gases at finite temperature for which the in-medium effective mass may not be constant as a function of the density, the temperature, or the chemical potential. We suggest a formalism that separates the terms for which the mass is constant from the terms which explicitly treat the correction due to the in-medium effective mass. We employ the ensemble equivalence in infinite matter in order to treat these different terms. Our formalism is applied in nuclear matter and we show its goodness by comparing it to an exact treatment based on the numerical calculation of the Fermi integrals.
Comments:
11 pages, 2 figures, 3 tables
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2304.14715 [pdf]
ApJ(2023)·2 citations
03
[Submitted on 27 Apr 2023] (cross-list from hep-ph)
Superfast Quarks in Deuterium
Dmitriy N. Kim🇺🇸 · Gerald A. Miller🇺🇸
An extension to our previous study on Nuclear Parton Distribution Functions (nPDFs) using Light-Front Holographic Quantum Chromodynamics (LFHQCD) is presented. We focus on applying the effects of nucleon motion inside the nucleus (Fermi motion/smearing) to deuterium, extending our nPDFs (and hence the DIS $F_{2}$ structure function for deuterium, $F_{2}^{D}$ ) to the superfast, $x > 1$ , region. We utilize four different deuteron wavefunctions (AV18, NijmI, NijmII, Nijm93) in this study. We find that our model, with no additional new parameters, is in excellent agreement with deuterium EMC ratio data obtained from the BONuS experiment. Looking beyond conventional nuclear physics, and in anticipation of ongoing 12 GeV experiments at Jefferson Lab, we use a LFHQCD ansatz to predict the contributions of an exotic six-quark state to $F_{2}^{D}$ in the superfast region. Our results are that the effects of using other potentials are about the same magnitude as six-quark effects - both have small effects in $x < 1$ , but have significant contributions at $x > 1$ .
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2304.14552 [pdf]
PRC(2024)·0 citations
04
[Submitted on 27 Apr 2023] (cross-list from hep-th)
Causality and stability in first-order conformal anisotropic hydrodynamics
Fabio S. Bemfica🇧🇷 · Mauricio Martinez🇺🇸 · Masoud Shokri🇩🇪
We formulate the first-order dissipative anisotropic hydrodynamical theory for a relativistic conformal uncharged fluid, which generalizes the Bemfica-Disconzi-Noronha-Kovtun first-order viscous fluid framework. Our approach maintains causal behavior in the nonlinear regime with or without general relativity coupling, and we derive and analyze the constraints on transport coefficients imposed by causality. We demonstrate the causal and stable behavior of our theory in specific cases, including the discussion of nonlinear causality as well as stability for linearized perturbations. We apply our newly developed first-order anisotropic theory to the Bjorken flow and show how causality and stability impose constraints on the behavior of the early-time attractor.
Comments:
Matches the published version
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th); Fluid Dynamics (physics.flu-dyn)
arXiv:
2304.14563 [pdf]
PRD(2023)·6 citations
05
[Submitted on 28 Apr 2023] (cross-list from hep-ph)
Conserved number fluctuations under global rotation in a hadron resonance gas model
Gaurav Mukherjee🇮🇳 · Dipanwita Dutta🇮🇳 · Dipak Kumar Mishra🇮🇳
Net-baryon number, net-charge and net-strangeness fluctuations measured in ultra-relativistic heavy-ion collisions may reveal details and insights into the quark-hadron transition, hadrochemical freeze-out and possibly aid in the search of the QCD critical point. By scanning in collision energy, current and upcoming heavy-ion facilities aim to explore the finite density regime where the critical point may lie. Effects due to rotation are also expected in case of peripheral collisions and we report on conserved number susceptibilities as calculated in the hadron resonance gas model augmented by a global angular velocity. Since these quantities are directly related to the experimentally measurable moments of the corresponding distributions our results show the possible impact of vorticity on the theoretical baseline and should be useful for referencing with experimental data and QCD-based calculations.
Comments:
9 pages, 6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2304.14658 [pdf]
EPJC(2024)·13 citations
06
[Submitted on 28 Apr 2023] (cross-list from hep-ph)
Building models of quarks and gluons with an arbitrary number of colors using Cartan-Polyakov loops
Renan Câmara Pereira🇵🇹 · Pedro Costa🇵🇹
In this work we introduce the concept of Cartan-Polyakov loops, a special subset of Polyakov loops in the fundamental representation of the $SU (N_{c})$ group, with charges $k = 1, \dots, (N_{c} - 1) /2$ . It constitutes a sufficient set of independent degrees of freedom and it is used to parametrize the thermal Wilson line. Polyakov loops not contained in this set are classified as non-Cartan-Polyakov loops. Using properties of the characteristic polynomial of the thermal Wilson line, we write a non-Cartan-Polyakov loop charge decomposition formula. This formalism allows one to readily build effective models of quarks and gluons with an arbitrary number of colors. We apply it to the Polyakov $-$ Nambu $-$ Jona-Lasinio model and to an effective glue model, in the mean field approximation, showing how to directly extend these models to higher values of $N_{c}$ .
Comments:
28 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2304.14751 [pdf]
NPB(2024)·2 citations
07
[Submitted on 28 Apr 2023] (cross-list from hep-ph)
Molecular charmed baryons and pentaquarks from light-meson exchange saturation
Mao-Jun Yan🇨🇳 · Fang-Zheng Peng🇨🇳 · Manuel Pavon Valderrama🇨🇳
The spectrum of the $c q q$ baryons contains a few states whose nature is not clearly a three-quark composite and which might have a sizable baryon-meson component. Examples include the $Σ_{c} (2800)$ or the $Λ_{c} (2940)$ . Here we explore the spectrum of two-body systems composed of a light, octet baryon and a charmed meson (or antimeson) within a simple contact-range theory in which the couplings are saturated by light-meson exchanges. This results in the prediction of a series of composite anticharmed pentaquarks ( $c ˉ q q q q$ ) and singly-charmed baryons ( $c q ˉ q q q$ ). Among the later we find $J = \frac{1}{2}$ $Ξ D$ and $J = \frac{3}{2}$ $Ξ D^{*}$ bound states with masses matching those of the recently observed $Ω_{c} (3185)$ and $Ω_{c} (3327)$ baryons.
Comments:
14 pages, 6 tables, corresponds to published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2304.14855 [pdf]
PRD(2024)·29 citations
08
[Submitted on 28 Apr 2023] (cross-list from hep-ph)
A contact interaction model for the $η$ and $η^{'}$ mesons in a SDE-BSE approach to QCD: masses, decay widths and transition form factors
Bilgai Almeida Zamora🇲🇽 · Enrique Carreon Martínez🇲🇽 · Jorge Segovia🇪🇸 · J.J. Cobos-Martínez🇲🇽
We construct a contact interaction model for the $η$ and $η^{'}$ mesons in the SDE-BSE approach to QCD and compute several static properties of these mesons and their transition form factors. We find that this model gives an excellent description of the $η$ and $η^{'}$ static properties, namely their masses, decay width and decay constants. However, a contact interaction disagrees with experimental data for $Q^{2}$ greater than 2 GeV $^{2}$ , and produces transition form factors in conflict with perturbative QCD prediction. This is not surpring and the reasons for this are explained
Comments:
10 pages, 4 figures, submitted to PRD
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2304.14887 [pdf]
PRD(2023)·10 citations

Affiliations

first authorsco-authorsvia INSPIRE