Nuclear Theory·nucl-th

Tuesday·April 30, 2024

15 papers—7 primary·8 cross-listed

08
A three-parameter characterization of neutron stars' mass-radius relation and equation of state
Dmitry D. Ofengeim · Peter S. Shternin · Tsvi Piran
Numerous models of neutron star (NS) equation of state (EoS) exist based on different superdense-matter physics approaches. Nevertheless, some NS properties show universal (EoS-independent) relations. Here, we propose a novel class of such universalities. Despite different physics inputs, a wide class of realistic nucleonic, hyperonic, and hybrid EoS models can be accurately described using only three parameters. For a given EoS, these are the mass and radius of the maximum-mass NS (or pressure and density in its center) and the radius of a half-maximum-mass star. With such a parametrization, we build universal analytic expressions for mass-radius and pressure-density relations. They form a semi-analytic mapping from the mass-radius relation to the EoS in NS cores (the so-called inverse Oppenheimer-Volkoff mapping). This mapping simplifies the process of inferring the EoS from observations of NS masses and radii. Applying it to current NS observations we set new limits on the high-density end of the EoS.
↳ astro-ph.HEnucl-thPRD(2024)·12 citations
09
The properties of $ϕ (2170)$ and its three-body nature
A. Martinez Torres🇧🇷 · Brenda B. Malabarba🇧🇷 · K. P. Khemchandani🇧🇷
We summarize the results we obtained for the partial decay widths of $ϕ (2170)$ into two-body final states formed by a $K ˉ$ and a Kaonic resonance, like $K (1460)$ , $K_{1} (1270)$ , as well as to final states constituted by a $ϕ$ and an $η / η^{'}$ mesons. The results obtained are compared with the values extracted from experimental data on the corresponding branching ratios, which were determined by the BESIII collaboration. A reasonable agreement is found, which together with the previous reproduction of the mass, width, and cross section for the process $e^{+} e^{-} \to ϕ f_{0}$ strongly indicates the molecular nature of $ϕ (2170)$ as a $ϕ K K ˉ$ system.
↳ hep-phnucl-thEPJ Web Conf.(2024)·1 citation
10
Detailed derivation of the $^{3} P_{0}$ strong decay model applied to baryons
T. Aguilar🇪🇨 · A. Capelo-Astudillo🇪🇨 · M. Conde-Correa🇪🇨 · A. Duenas-Vidal🇪🇨 · P. G. Ortega🇪🇸 · J. Segovia🇪🇸
We provide an in-detail derivation through the $^{3} P_{0}$ pair creation model of the transition matrix for a baryon decaying into a meson-baryon system. The meson's analysis was conducted in Ref. [1] and we extend the same formalism to the baryon sector, focusing on the $Δ (1232) \to π N$ strong decay width because all hadrons involved in the reaction are very well established, the two hadrons in the final state are stable, avoiding further analysis, all quarks are light and so equivalent, and the decay width of the process is relatively well measured. Taking advantage of a Gaussian expansion method for the hadron's radial wave functions, the expression of the invariant matrix element can be related with the mean-square radii of hadrons involved in the decay. We use their experimental measures in such a way that only the strength of the quark-antiquark pair creation from the vacuum is a free parameter. This is then taken from our previous study of strong decay widths in the meson sector, obtaining a quite compatible result with experiment for the calculated $Δ (1232) \to π N$ decay width.
↳ hep-phhep-exhep-latnucl-ex+1CPC(2025)·1 citation
11
Femtoscopy can tell whether $Z_{c} (3900)$ and $Z_{cs} (3985)$ are resonances or virtual states
Zhi-Wei Liu🇨🇳 · Jun-Xu Lu🇨🇳 · Ming-Zhu Liu🇨🇳 · Li-Sheng Geng🇨🇳
There have been extended and heated discussions on the nature of the two exotic states, $Z_{c} (3900)$ and $Z_{cs} (3985)$ , particularly whether they are near-threshold resonances, virtual states, or bound states. In this work, we demonstrate for the first time that the femtoscopic technique can be employed to distinguish between these three scenarios. More concretely, based on the Koonin-Pratt formula with a Gaussian source, we show that the low-momentum $D^{0} D^{*-}$ / $D^{0} D_{s}^{*-}$ correlation functions significantly differ in the three scenarios. The high-momentum results exhibit distinct characteristics in the resonant and virtual state scenarios, especially in small collision systems of 1 fm, as produced in $pp$ collisions at the LHC. We hope that these discoveries will stimulate further experimental studies and help clarify the nature of the many exotic states that have been discovered.
↳ hep-phhep-exnucl-exnucl-thSci.Bull.(2025)·36 citations
12
Mass Spectra of $Ξ$ and $Ω$ Baryons using hypercentral Constituent Quark Model
Chandni Menapara🇮🇳 · Ajay Kumar Rai🇮🇳
Hadron spectroscopy is an important tool towards the study of internal quark dynamics in a composite system. The present article focuses on the study of resonance spectra of strange baryons with S=-2, -3. The non-relativistic approach utilizes screened potential as hypercentral one to obtain masses. The spin-dependent part for all possible hyperfine states has been incorporated.
↳ hep-phnucl-thNuovo Cim.C(2024)·2 citations
13
Computing Scattering Cross Sections For Spherically Symmetric Potentials
Anil Khachi
This paper introduces students and instructors to the use of Scilab for calculating phase shifts from phenomenological potentials in nuclear, atomic, and molecular scattering, beginning with a Riccati-type nonlinear differential equation derived from the time-independent Schr $o ¨$ dinger equation. For spherically symmetric potentials, this equation can be easily solved using Xcos, a Scilab toolbox. \cite{PRC}\cite{bobby} Scilab is open source software that is used for numerical computations and can be freely downloaded for Windows, Linux and Mac OS.\cite{scilab} Xcos is a Scilab toolbox dedicated to the modeling and simulation of hybrid dynamic systems \cite{rachna}. Xcos provides users with the ability to model complex dynamical systems using a block diagram editor (GUI based), offering a step-by-step procedure for learning to solve complex differential equations interactively.
↳ physics.ed-phnucl-thAm.J.Phys.(2024)·1 citation
14
Diffusion coefficient matrix for multiple conserved charges: a Kubo approach
Sourav Dey🇮🇳 · Amaresh Jaiswal🇮🇳 · Hiranmaya Mishra🇮🇳
The strongly interacting matter created in relativistic heavy-ion collisions possesses several conserved quantum numbers, such as baryon number, strangeness, and electric charge. The diffusion process of these charges can be characterized by a diffusion matrix that describes the mutual influence of the diffusion of various charges. We derive the Kubo relations for evaluating diffusion coefficients as elements of a diffusion matrix. We further demonstrate that in the weak coupling limit, the diffusion matrix elements obtained through Kubo relations reduce to those obtained from kinetic theory with an appropriate identification of the relaxation times. We illustrate this evaluation in a toy model of two interacting scalar fields with two conserved charges.
↳ hep-phhep-thnucl-thJHEP(2024)·10 citations
15
An unconventional deformation of the nonrelativistic spin-1/2 Fermi gas
Vimal Palanivelrajan · Joaquín E. Drut
We explore a generalization of nonrelativistic fermionic statistics that interpolates between bosons and fermions, in which up to $K$ particles may occupy a single-particle state. We show that it can be mapped exactly to $K$ flavors of fermions with imaginary polarization. In particular, for $K = 2$ , we use such a mapping to derive the virial coefficients and relate them to those of conventional spin-1/2 fermions in an exact fashion. We also use the mapping to derive next-to-leading-order perturbative results for the pressure equation of state. Our results indicate that the $K = 2$ particles are more strongly coupled than conventional spin- $1/2$ fermions, as measured by the interaction effects on the virial expansion and on the pressure equation of state. In the regime set by the unitary limit, the proposed $K = 2$ deformation represents a universal many-body system whose properties remain largely unknown. In particular, the system can be expected to become superfluid at a critical temperature $T_{c}$ higher than that of the unitary limit. We suggest it may be possible to realize this system experimentally by engineering a polarized coupling to an electrostatic potential. Finally, we show that the $K = 2$ system does not display a sign problem for determinantal Monte Carlo calculations, which indicates that $T_{c}$ can at least in principle be calculated with conventional methods.
↳ cond-mat.quant-gasnucl-th0 citations

Affiliations

first authorsco-authorsvia INSPIRE