Nuclear Theory·nucl-th

Friday·August 9, 2024

7 papers—2 primary·5 cross-listed

01
Charmed hypernuclei within density-dependent relativistic mean-field theory
Wei Yang🇨🇳 · Shi Yuan Ding🇨🇳 · Bao Yuan Sun🇨🇳
The charmed $Λ_{c}^{+}$ hypernuclei are investigated within the framework of the density-dependent relativistic mean-field (DDRMF) theory. Starting from the empirical hyperon potential in symmetric nuclear matter, obtained through microscopic first-principle calculations, two sets of $Λ_{c} N$ effective interactions were derived by fitting the potentials with minimal uncertainty (Fermi momentum $k_{F, n} = 1.05 fm^{- 1}$ ) and near saturation density ( $k_{F, n} = 1.35 fm^{- 1}$ ). These DDRMF models were then used to explore the $Λ_{c} N$ effective interaction uncertainties on the description of hypernuclear bulk and single-particle properties. A systematic investigation was conducted on the existence of bound $Λ_{c}^{+}$ hypernuclei. The dominant factors affecting the existence and stability of hypernuclei were analyzed from the perspective of the $Λ_{c}^{+}$ potential. It is found that the hyperon potential is not only influenced by the Coulomb repulsion, but by an extra contribution from the rearrangement terms due to the density dependence of the meson-baryon coupling strengths. Therefore, the rearrangement term significantly impacts the stability description for light hypernuclei, while for heavier hypernuclei, the contribution from Coulomb repulsion becomes increasingly significant and eventually dominant. The discussion then delves into the bulk and single-particle properties of charmed hypernuclei using these models. It is found that even when different models yield similar hyperon potentials for nuclear matter, different treatments of nuclear medium effects could lead to disparities in the theoretical description of hypernuclear structures. This study indicates that constraints on the $Λ_{c} N$ interaction at finite densities are crucial for the study of $Λ_{c}^{+}$ hypernuclear structures.
nucl-thPRC(2024)·4 citations
02
Convergence properties of $T^{'}$ -Expansion Scheme: Hadron Resonance Gas and Cluster Expansion Model
Micheal Kahangirwe🇺🇸 · Irene Gonzalez🇺🇸 · Jorge A. Muñoz🇺🇸 · Claudia Ratti🇺🇸 · Volodymyr Vovchenko🇺🇸
In this study, we assess the effectiveness and robustness of the recently proposed $T^{'}$ -expansion scheme for expanding the equation of state of strongly interacting matter to finite density, by comparing its performance relative to the conventional Taylor expansion method in various effective QCD models. We use baryon number density and its susceptibilities to calculate the expansion coefficients in the $T^{'}$ -expansion scheme with and without the Stefan-Boltzmann limit correction. Our methodology involves comparing truncation orders to exact solutions to assess the scheme's accuracy. We utilize Ideal, Excluded Volume, and van der Waals formulations of the Hadron Resonance Gas (HRG) model at low temperatures, and the Cluster Expansion Model at higher temperatures. Our findings indicate that the $T^{'}$ -expansion scheme offers superior convergence properties near and above the chiral crossover temperature, where the chiral-criticality-inspired scaling $(\partial / \partial T)_{μ_{B}} \sim (\partial^{2} / \partial μ_{B}^{2})_{T}$ holds. However, it shows limited improvement in the HRG models, indicating that it may not be the most suitable choice for describing the hadronic phase.
nucl-thPRD(2025)·10 citations
03
X(2370) glueball-like particle productions in $e^{+} e^{-}$ collisions at the BESIII energy and in pp collisions at the LHC energy with PACIAE model
Jian Cao🇨🇳 · Zhi-Lei She🇨🇳 · Jin-Peng Zhang🇨🇳 · Jia-Hao Shi🇨🇳 · Zhi-Ying Qin🇨🇳 · Wen-Chao Zhang🇨🇳 · Hua Zheng🇨🇳 · An-Ke Lei🇨🇳 · Dai-Mei Zhou🇨🇳 · Yu-Liang Yan🇨🇳 · Ben-Hao Sa🇨🇳
Inspired by the BESIII newest observation of X(2370) glueball-like particle, we search its productions in both $e^{+} e^{-}$ collisions at $s =$ 4.95 GeV and proton-proton (pp) collisions at $s =$ 13 TeV with a parton and hadron cascade model PACIAE. In this model, the final partonic state (FPS) and the final hadronic state (FHS) are consecutively simulated and recorded. The X(2370) glueball- or tetraquark-state is then, respectively, recombined by two gluons or four quarks $ss s ˉ s ˉ$ in the FPS using the quantum statistical mechanics inspired dynamically constrained phase-space coalescence (DCPC) model. The X(2370) molecular-state is recombined by the baryon-antibaryon of $Λ$ - $Λ ˉ$ or $Σ$ - $Σ ˉ$ , or by three mesons of $π^{+} π^{-} η^{'}$ , $K^{+} K^{-} η^{'}$ , or $K_{S}^{0} K_{S}^{0} η^{'}$ in the FHS using DCPC model. In both $e^{+} e^{-}$ and pp collisions, significant discrepancies in the yields, the transverse momentum spectra and the rapidity distributions among the X(2370) glueball-, tetraquark-, and molecular-state are observed. These discrepancies are proposed as valuable criteria identifying the X(2370) different states from each other. Our results not only support the BESIII observation of glueball-like particle $X (2370)$ production in $e^{+} e^{-}$ collisions, but also serve as a prediction for the $X (2370)$ production in pp collisions. We strongly suggest the experimental measurement of the X(2370) glueball-like particle production in pp collisions at the LHC energies.
↳ hep-phnucl-thPRD(2024)·11 citations
04
On convergence properties of GPD expansion through Mellin/conformal moments and orthogonal polynomials
Hao-Cheng Zhang🇨🇳 · Xiangdong Ji🇺🇸
We examine convergence properties of reconstructing the generalized parton distributions (GPDs) through the universal moment parameterization (GUMP). We provide a heuristic explanation for the connection between the formal summation/expansion and the Mellin-Barnes integral in the literature, and specify the exact convergence condition. We derive an asymptotic condition on the conformal moments of GPDs to satisfy the boundary condition at $x = 1$ and subsequently develop an approximate formula for GPDs when $x > ξ$ . Since experimental observables constraining GPDs can be expressed in terms of double or even triple summations involving their moments, scale evolution factors, and Wilson coefficients, etc., we propose a method to handle the ordering of the multiple summations and convert them into multiple Mellin-Barnes integrals via analytical continuations of integer summation indices.
↳ hep-phhep-latnucl-thNPB(2025)·3 citations
05
Photonuclear reactions on $^{59}$ Co at bremsstrahlung end-point energies of 40-130 MeV
F.A. Rasulova · S.S. Belyshev · M.A. Demichev · D.L. Demin · S.A. Evseev · N.Yu. Fursova · M.I. Gostkin · J.H. Khushvaktov · V.V. Kobets · A.A. Kuznetsov · S.V. Rozov · E.T. Ruziev and 4 other authors
Relative yields have been measured in the 40-130 MeV bremsstrahlung induced reactions of 59Co. The experiments have been performed with the beam from the electron linear accelerator LINAC-200 using the activation and off-line {\gamma}-ray spectrometric technique. The bremsstrahlung photon flux has been calculated with the Geant4 program. The cross sections were calculated by using computer code TALYS-1.96 with different models and are found to be in good agreement with the experimental data.
↳ nucl-exnucl-thCPC(2024)·0 citations
06
Spin polarization of $Λ$ hyperons along beam direction in p+Pb collisions at $s_{N N} = 8.16$ TeV using hydrodynamic approaches
Cong Yi🇨🇳 · Xiang-Yu Wu🇨🇦 · Jie Zhu🇨🇳 · Shi Pu🇨🇳 · Guang-You Qin🇨🇳
We have implemented the 3+1 dimensional CLVisc hydrodynamics model with TRENTO-3D initial conditions to investigate the spin polarization of $Λ$ hyperons along the beam direction in p+Pb collisions at $s_{N N} = 8.16$ TeV. Following our previous theoretical framework based on quantum kinetic theory, we consider three different scenarios: $Λ$ equilibrium, $s$ quark equilibrium, and iso-thermal equilibrium scenarios. We have computed the second Fourier sine coefficients of spin polarization along the beam direction, denoted as $⟨ P_{z} sin 2 (ϕ_{p} - Ψ_{2}) ⟩$ , with $ϕ_{p} - Ψ_{2}$ being the azimuthal angle relative to the second-order event plane $Ψ_{2}$ , as functions of multiplicity, transverse momentum and pseudo-rapidity in the three scenarios. Additionally, we have also computed the spin polarization along the beam direction, $P_{z}$ , as a function of the azimuthal angle. We find that the spin polarization induced by thermal vorticity always provides an opposite contribution compared to the shear-induced polarization in p+Pb collisions. The total spin polarization computed by the current hydrodynamic model disagrees with the data measured by LHC-CMS experiments. Our findings imply that other non-flow effects may play a crucial role in p+Pb collisions.
↳ hep-phnucl-thPRC(2025)·17 citations
07
Speed of sound and isothermal compressibility in a magnetized quark matter with anomalous magnetic moment of quarks
Rajkumar Mondal🇮🇳 · Sourav Duari🇮🇳 · Nilanjan Chaudhuri🇮🇳 · Sourav Sarkar🇮🇳 · Pradip Roy🇮🇳
We study the characteristics of quark matter under the influence of a background magnetic field with anomalous magnetic moment (AMM) of quarks at finite temperature and quark chemical potential in the framework of Polyakov loop extended Nambu Jona-Lasinio (PNJL) model. In presence of a magnetic field, the speed of sound and isothermal compressibility become anisotropic with respect to the direction of the background magnetic field, splitting into parallel and perpendicular directions with respect to the magnetic field. Though the qualitative nature of parallel and perpendicular components of squared speed of sound appear similar, they differ in magnitude at lower values of temperature. The parallel and perpendicular components of isothermal compressibility decrease with increasing temperature, indicating a trend towards increased incompressible strongly interacting matter. On inclusion of the AMM of quarks, the perpendicular component of isothermal compressibility becomes greater than the parallel component. Additionally, we investigate the quark number susceptibility normalized by its value at zero magnetic field, which may indicate the presence of magnetic fields in the system.
↳ hep-phnucl-thPRD(2024)·10 citations

Affiliations

first authorsco-authorsvia INSPIRE

Charmed hypernuclei within density-dependent relativistic mean-field theory

Convergence properties of T′-Expansion Scheme: Hadron Resonance Gas and Cluster Expansion Model

X(2370) glueball-like particle productions in e+e− collisions at the BESIII energy and in pp collisions at the LHC energy with PACIAE model

On convergence properties of GPD expansion through Mellin/conformal moments and orthogonal polynomials

Photonuclear reactions on 59Co at bremsstrahlung end-point energies of 40-130 MeV

Spin polarization of Λ hyperons along beam direction in p+Pb collisions at sNN​​=8.16 TeV using hydrodynamic approaches

Speed of sound and isothermal compressibility in a magnetized quark matter with anomalous magnetic moment of quarks

Affiliations

Convergence properties of $T^{'}$ -Expansion Scheme: Hadron Resonance Gas and Cluster Expansion Model

X(2370) glueball-like particle productions in $e^{+} e^{-}$ collisions at the BESIII energy and in pp collisions at the LHC energy with PACIAE model

Photonuclear reactions on $^{59}$ Co at bremsstrahlung end-point energies of 40-130 MeV

Spin polarization of $Λ$ hyperons along beam direction in p+Pb collisions at $s_{N N} = 8.16$ TeV using hydrodynamic approaches