Nuclear Theory·nucl-th

Monday·May 9, 2022

7 papers—3 primary·4 cross-listed

01
[Submitted on 5 May 2022]
What has been learnt from the analysis of the low-energy pion-nucleon data during the past three decades?
Evangelos Matsinos🇨🇭
Over twenty-five years ago, two analyses of the pion-nucleon ( $π N$ ) data at low energy (i.e., for pion laboratory kinetic energy $T \leq 100$ MeV) reported on the departure of the extracted scattering amplitudes, corresponding to the two elastic-scattering reactions $π^{\pm} p \to π^{\pm} p$ and to the $π^{-} p$ charge-exchange reaction $π^{-} p \to π^{0} n$ , from the triangle identity, which these amplitudes fulfil if the isospin invariance holds in the hadronic part of the $π N$ interaction. This discrepancy indicates that \emph{at least one} of the following assumptions is not valid: first, that the absolute normalisation of the bulk of the low-energy $π N$ datasets is correct; second, that any residual contributions to the corrections, which aim at the removal of the effects of electromagnetic (EM) origin from the measurements, are not significant; and third, that the isospin invariance holds in the hadronic part of the $π N$ interaction. In view of the incompatibility of the results of the various schemes of removal of the so-called trivial EM effects at the $π N$ threshold ( $T = 0$ MeV), the likelihood of residual effects of EM origin in the extracted $π N$ scattering amplitudes (from the data in the scattering region, i.e., above the $π N$ threshold) must be reassessed. This work emphasises the importance of the development of a unified scheme for the determination of reliable EM corrections, \emph{applicable at the $π N$ threshold and in the scattering region}, in providing a resolution to the established discrepancy at low energy.
Comments:
60 pages, 11 figures, 3 tables. Changes to the first version: minor occasional modifications to improve readability; correction of one mistake on p. 44 (of the first version), two lines before Eq. (17); addition of three references: [34], [63], and [65] (updated version). No numerical values have been changed: the tables and the figures are identical to those of the first version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2205.02899 [pdf]
3 citations
02
[Submitted on 6 May 2022]
Resonance nucleon scattering amplitude in the photonuclear reaction
Swapan Das🇮🇳
The cross section of the photonuclear reaction in the nucleon-resonance region is calculated to search the resonance-nucleon scattering amplitude in the nucleus. It is assumed that the resonance $R$ is produced and decayed in the elementary photon-nucleon $(γ N)$ reaction in the nucleus as $γ N \to R \to γ N$ . The resonance interacts with the nucleons while propagating through the nucleus. Therefore, the calculated photonuclear reaction cross section is compared with the data to extract the resonance-nucleon scattering parameters in the nucleus.
Comments:
17 pages, 6 Figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2205.03025 [pdf]
NPA(2023)·0 citations
03
[Submitted on 6 May 2022]
Equations of state for hot neutron stars -- II. The role of exotic particle degrees of freedom
Adriana R. Raduta🇷🇴
Explosive astrophysical systems - such as supernovae or compact star binary mergers - provide conditions where exotic degrees of freedom can be populated. Within the covariant density functional theory of nuclear matter we build several general purpose equations of state which, in addition to the baryonic octet, account for $Δ (1232)$ resonance states. The thermodynamic stability of $Δ$ -admixed nuclear matter is investigated in the limiting case of vanishing temperature for charge fractions $Y_{Q} = 0.01$ and $Y_{Q} = 0.5$ and wide ranges of the coupling constants to the scalar and vector mesonic fields. General purpose equation of state models with exotica presently available on the \textsc{CompOSE} database are further reviewed; for a selection of them we then investigate thermal properties for thermodynamic conditions relevant for core-collapse supernovae and binary neutron star mergers. Modifications induced by hyperons, $Δ (1232)$ , $K^{-}$ , pions and quarks are discussed.
Comments:
26 pages; 22 figures; contribution to the EPJ A Topical Issue "CompOSE: a repository for Neutron Star Equations of State and Transport Properties"
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2205.03177 [pdf]
EPJA(2022)·50 citations
04
[Submitted on 5 May 2022] (cross-list from hep-lat)
Strongly Bound Dibaryon with Maximal Beauty Flavor from Lattice QCD
Nilmani Mathur🇮🇳 · M. Padmanath🇩🇪 · Debsubhra Chakraborty🇮🇳
We report the first lattice QCD study of the heavy dibaryons in which all six quarks have the bottom (beauty) flavor. Performing a state-of-the-art lattice QCD calculation we find clear evidence for a deeply bound $Ω_{bbb}$ - $Ω_{bbb}$ dibaryon in the $^{1} S_{0}$ channel, as a pole singularity in the $S$ -wave $Ω_{bbb}$ - $Ω_{bbb}$ scattering amplitude with a binding energy $- 81 (_{- 16}^{+ 14})$ MeV. With such a deep binding, Coulomb repulsion serves only as a perturbation on the ground state wave function of the parameterized strong potential and may shift the strong binding only by a few percent. Considering the scalar channel to be the most bound for single flavored dibaryons, we conclude this state is the heaviest possible most deeply bound dibaryon in the visible universe.
Comments:
4 figures, 1 table
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2205.02862 [pdf]
PRL(2023)·54 citations
05
[Submitted on 6 May 2022] (cross-list from hep-ph)
J-PARC hadron physics and future possibilities on color transparency
S. Kumano🇯🇵
The J-PARC is a hadron-accelerator facility to provide secondary beams of kaons, pions, neutrinos, muons, and the others together with the primary proton beam for investigating a wide range of science projects. High-energy hadron physics can be studied by using high-momentum beams of unseparated hadrons, which are essentially pions, and also primary protons. In this report, possible experiments are explained on color transparency and generalized parton distributions (GPDs). These projects are complementary to lepton-scattering experiments at JLab, COMPASS/AMBER, and future electron-ion colliders. Because of hadron-beam energies up to 30 GeV, the J-PARC is a unique facility to investigate the transition region from the hadron degrees of freedom to the quark-gluon one. It is suitable for finding mechanisms of the color transparency. Such color-transparency studies are also valuable for clarifying factorization of hadron-production processes in extracting the GPDs from actual measurements. These studies will lead to the understanding of basic high-energy hadron interactions in nuclear medium and to clarifications on the origins of hadron spins, masses, and internal pressure mechanisms.
Comments:
8 pages, LaTeX, Proceedings of the Workshop on The Future of Color Transparency and Hadronization Studies at Jefferson Lab and Beyond, June 7-8, 2021, (Online) USA-eastern time (MSU/Orsay/FIU/Penn State)
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2205.03012 [pdf]
MDPI Physics(2022)·9 citations
06
[Submitted on 6 May 2022] (cross-list from gr-qc)
Wave Phenomena In General Relativistic Magnetohydrodynamics
Ankit Kumar Panda🇮🇳 · Victor Roy🇮🇳
Here we study the wave propagation and stability of general relativistic non-resistive dissipative second-order magnetohydrodynamic equations in curved space-time. We solve the Boltzmann equation for a system of particles and antiparticles using the relaxation time approximation and the Chapman-Enskog-like gradient expansion for the off-equilibrium distribution function, truncating beyond second-order in curved space-time in electromagnetic fields. Unlike holographic calculation~\cite{Baier:2007ix}, we show that the viscous evolution equations do not explicitly depend on the curvature of space-time. Also, we have tested the causality and stability of the second-order theory in curved space-time in the presence of linearised metric perturbation and derived dispersion relations for various modes. Interestingly, we found the coupling of gravitational modes with the usual magneto-sonic modes in the small wave-number limit. Also, we show additional non-hydrodynamical modes arise due to gravity for a bulk-viscous fluid.
Comments:
17 pages, 2 figures
Subjects:
General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th); Fluid Dynamics (physics.flu-dyn)
arXiv:
2205.03107 [pdf]
3 citations
07
[Submitted on 6 May 2022] (cross-list from hep-ph)
Conductivity, diffusivity, and violation of Wiedemann-Franz Law in a hadron resonance gas with van der Waals interactions
Kshitish Kumar Pradhan🇮🇳 · Dushmanta Sahu🇮🇳 · Ronald Scaria🇮🇳 · Raghunath Sahoo🇮🇳
In this work, a hadron resonance gas under van der Waals (VDW) interactions has been studied. Both attractive and repulsive interactions between the meson-meson and (anti)baryon-(anti)baryon have been taken into consideration. Various transport properties such as electrical conductivity ( $σ_{el}$ ) and thermal conductivity ( $κ_{th}$ ) have been estimated by solving the Boltzmann transport equation under the relaxation time approximation. The effect of baryochemical potential ( $μ_{B}$ ) and temperature is also explicitly explored for the mentioned observables. Comparisons have been made with the results obtained from other existing theoretical models. We observe the violation of Wiedemann-Franz law in a hadron resonance gas at a high-temperature regime. The corresponding diffusivities have also been estimated, which can help us to understand the system in a better way.
Comments:
Same as the published version in Phys. Rev. C
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2205.03149 [pdf]
PRC(2023)·32 citations

Affiliations

first authorsco-authorsvia INSPIRE

What has been learnt from the analysis of the low-energy pion-nucleon data during the past three decades?

Resonance nucleon scattering amplitude in the photonuclear reaction

Equations of state for hot neutron stars -- II. The role of exotic particle degrees of freedom

Strongly Bound Dibaryon with Maximal Beauty Flavor from Lattice QCD

J-PARC hadron physics and future possibilities on color transparency

Wave Phenomena In General Relativistic Magnetohydrodynamics

Conductivity, diffusivity, and violation of Wiedemann-Franz Law in a hadron resonance gas with van der Waals interactions

Affiliations