Nuclear Theory·nucl-th

Friday·September 24, 2021

8 papers—7 primary·1 cross-listed

01
Application of the Lagrange mesh method in continuum-discretized coupled-channels calculations
Wendi Chen · Hairui Guo · Weili Sun · Tao Ye · Yangjun Ying · Yinlu Han
We apply the Lagrange-mesh method to discretize continuum states of weakly bound nuclei for continuum-discretized coupled-channel (CDCC) calculations of three-body breakup reactions. This discretization method is compared with the bin method, which is regarded as the standard continuum discretization method, for the $d$ and $^{6}$ Li induced reactions. An improved Numerov algorithm is used to solve the coupled channels equations, which permits a fast integration of equations and a convenient treatment of the closed channels. A new CDCC model code named \emph{CDCC-R} is developed. In all cases, the combination of the Lagrange-mesh method and the Numerov algorithm shows high efficiency and accuracy for the CDCC calculations of the elastic scattering and breakup reactions. Especially, various numerical and physical aspects are discussed for $^{6}$ Li induced reactions. The coupling effects of the continuum states with high orbital angular momentum and closed channels are discussed. Moderate effects are found in the calculations for elastic scattering and breakup reaction when $F$ - and $G$ -wave continuum states are included in CDCC model space for $^{6}$ Li induced reactions at the incident energies well above the Coulomb barrier. The closed channel effect is found to be indispensable for $^{6}$ Li breakup reaction calculation when the incident energy is around the Coulomb barrier.
nucl-thJ.Phys.G(2022)·10 citations
02
Charmonium in nuclear matter and nuclei
J.J. Cobos Martínez🇲🇽 · K. Tsushima🇧🇷 · G. Krein🇧🇷 · A.W. Thomas🇦🇺
We present results for the $η_{c}$ -nucleus bound state energies for various nuclei using an effective Lagrangians approach. The attractive potentials for the $η_{c}$ in the nuclear medium originate from the medium-modified intermediate $D D^{*}$ state in the $η_{c}$ self energy, using the local density approximation. Our results suggest that the $η_{c}$ should form bound states with all the nuclei considered
nucl-thhep-exhep-phnucl-exPoS(2021)·1 citation
03
Effect of relaxation time on the squeezed correlations of bosons for evolution sources in relativistic heavy-ion collisions
Wei-Ning Zhang🇨🇳 · Peng-Zhi Xu🇨🇳
Squeezed back-to-back correlation (SBBC) of a boson-antiboson pair is sensitive to the time distribution of the particle-emitting source, and the SBBC function for an evolving source is expected to be affected by the relaxation time of the system. In this paper, we investigate the effect of relaxation time on the SBBC function. We put forth a method to calculate the SBBC function with relaxation-time modification for evolving sources. The SBBC functions of $D^{0} D ˉ^{0}$ in relativistic heavy-ion collisions are investigated by using a hydrodynamic model. It is found that the relaxation time reduces the amplitudes of the SBBC functions. This change becomes serious for a long relaxation time and large initial relative deviations of the chaotic and squeezed amplitudes from their equilibrium values, respectively, in the temporal steps.
nucl-thNucl.Sci.Tech.(2022)·1 citation
04
Basic quantities of the Equation of State in isospin asymmetric nuclear matter
Jie Liu · Chao Gao · Niu Wan · Chang Xu
Based on the Hugenholtz-Van Hove theorem, six basic quantities of the EoS in isospin asymmetric nuclear matter are expressed in terms of the nucleon kinetic energy $t (k)$ , the isospin symmetric and asymmetric parts of the single-nucleon potentials $U_{0} (ρ, k)$ and $U_{sym,i} (ρ, k)$ . The six basic quantities include the quadratic symmetry energy $E_{sym,2} (ρ)$ , the quartic symmetry energy $E_{sym,4} (ρ)$ , their corresponding density slopes $L_{2} (ρ)$ and $L_{4} (ρ)$ , and the incompressibility coefficients $K_{2} (ρ)$ and $K_{4} (ρ)$ . By using four types of well-known effective nucleon-nucleon interaction models, namely the BGBD, MDI, Skyrme, and Gogny forces, the density- and isospin-dependent properties of these basic quantities are systematically calculated and their values at the saturation density $ρ_{0}$ are explicitly given. The contributions to these quantities from $t (k)$ , $U_{0} (ρ, k)$ , and $U_{sym,i} (ρ, k)$ are also analyzed at the normal nuclear density $ρ_{0}$ . It is clearly shown that the first-order asymmetric term $U_{sym,1} (ρ, k)$ (also known as the symmetry potential in Lane potential) plays a vital role in determining the density dependence of the quadratic symmetry energy $E_{sym,2} (ρ)$ . It is also shown that the contributions from high-order asymmetric parts of the single-nucleon potentials ( $U_{sym,i} (ρ, k)$ with $i > 1$ ) cannot be neglected in the calculations of the other five basic quantities. Moreover, by analyzing the properties of asymmetric nuclear matter at the exact saturation density $ρ_{sat} (δ)$ , the corresponding quadratic incompressibility coefficient is found to have a simple empirical relation $K_{sat,2} = K_{2} (ρ_{0}) - 4.14 L_{2} (ρ_{0})$ .
nucl-thNucl.Sci.Tech.(2021)·17 citations
05
Nonlinear waves in a hot, viscous and nonextensive quark gluon plasma
Golam Sarwar🇮🇳 · Md Hasanujjaman🇮🇳 · Trambak Bhattacharyya🇷🇺 · Mahfuzur Rahaman🇮🇳 · Abhijit Bhattacharyya🇮🇳 · Jan-e Alam🇮🇳
The effects of the non-extensive statistics on the nonlinear propagation of perturbations have been studied within the scope of relativistic second order dissipative hydrodynamics with the non-extensive equation of state. We have shown that the equations, describing the propagation of nonlinear waves under such situation are KdV-type (Korteweg-De Vries). Apart from their preserved solitonic behaviour the dissipative nature of these waves are also observed. The waves with larger amplitude and width dissipate less and propagate faster and these waves deplete more for both smaller values of Tsallis parameter ( $q$ ) and temperature ( $T$ ) of the medium. For vanishingly small transport coefficients the nonlinear waves show breaking nature. These findings suggest that the nature of the propagation of the nonlinear waves may serve as a good probe to differentiate between the extensive and non-extensive thermodynamic nature of a fluid, such as the quark-gluon plasma, produced in relativistic nuclear collisions.
nucl-thEPJC(2022)·9 citations
06
Peripheral nucleon-nucleon scattering at next-to-next-to-leading order in SU(3) heavy baryon chiral perturbation theory
Bo-Lin Huang🇨🇳 · Jian-Bo Cheng🇨🇳 · Shi-Lin Zhu🇨🇳
We calculate the complete $T$ matrices of the elastic nucleon-nucleon scattering up to third order in SU(3) heavy baryon chiral perturbation theory. The phase shifts with orbital angular momentum $L \geq 2$ and the mixing angles with $J \geq 2$ are evaluated by using low-energy constants that were extracted from the meson-baryon analysis. It turns out that our prediction is consistent with the empirical phase shifts and mixing angles data, and also the results from SU(2) heavy baryon chiral perturbation theory. The errors from the low-energy constants are analyzed in detail. Our calculation provides reliable evidence that the nucleon-nucleon interaction calculated in SU(3) heavy baryon chiral perturbation theory leads to reasonable predictions.
nucl-thPRD(2021)·3 citations
07
Three-body resonances in pionless effective field theory
Sebastian Dietz🇩🇪 · Hans-Werner Hammer🇩🇪 · Sebastian König🇺🇸 · Achim Schwenk🇩🇪
We investigate the appearance of resonances in three-body systems using pionless effective field theory at leading order. The Faddeev equation is analytically continued to the unphysical sheet adjacent to the positive real energy axis using a contour rotation. We consider both, the three-boson system and the three-neutron system. For the former, we calculate the trajectory of Borromean three-body Efimov states turning into resonances as they cross the three-body threshold. For the latter, we find no sign of three-body resonances or virtual states at leading order. This result is validated by exploring the level structure of three-body states in a finite volume approach.
nucl-thnucl-exPRC(2022)·19 citations

Affiliations

first authorsco-authorsvia INSPIRE

Application of the Lagrange mesh method in continuum-discretized coupled-channels calculations

Charmonium in nuclear matter and nuclei

Effect of relaxation time on the squeezed correlations of bosons for evolution sources in relativistic heavy-ion collisions

Basic quantities of the Equation of State in isospin asymmetric nuclear matter

Nonlinear waves in a hot, viscous and nonextensive quark gluon plasma

Peripheral nucleon-nucleon scattering at next-to-next-to-leading order in SU(3) heavy baryon chiral perturbation theory

Three-body resonances in pionless effective field theory

Affiliations