Nuclear Theory·nucl-th
10 papers—6 primary·4 cross-listed
The effect of the pion propagator on the -decay of neutron is investigated to account for the ratio of the axial-vector to the vector part by including the pole term. A suggestion is made that the sign and the size of the vertex correction is appropriate to improve the discrepancy between the result of the model hamiltonian and the experiment.
S. Amano · Y. Aritomo · M. Ohta
The capture cross section, the fusion cross section, and the quasi-fission yield producing symmetric fragments () in the Ca+U reaction are analyzed by the multidimensional Langevin equation taking account of the surface friction effect. From the experimental data, the strength of the tangential friction has been determined. It is presented that tangential friction increases in proportional to the power of the relative velocity of the projectile and the target.
In this study, my main goal is to examine the nuclear matter properties across a wide range of conditions, such as temperature, density, asymmetry, pressure, and magnetic field. Understanding the effect of these factors on nuclear matter is essential, given their relevance in various phenomena such as heavy-ion collisions, neutron stars, and supernovae. However, due to the absence of a fundamental nuclear theory, we must rely on models to describe the nuclear matter. Predicted properties like neutron star mass-radius relationships, tidal deformability, structure, critical points in the nuclear matter phase diagram etc. depend on the chosen model. This dependence arises because key parameters characterizing any nuclear model or equation of state (EoS) are not precisely known. Therefore, it is crucial to investigate how nuclear matter properties behave under various conditions and in relation to different EoS parameters. To accomplish this, I have examined three distinct forms of nuclear matter: infinite nuclear matter, finite nuclei, and neutron stars, using the effective relativistic mean field model (E-RMF).
Solutions of shock waves in anisotropic relativistic hydrodynamics in the absence of refraction of the flow passing through the shock wave are considered. The existence of a critical value of the anisotropy parameter is shown. This value is the upper limit below which an adequate description of shock waves is possible. Shock wave solutions also provide a mechanism for system isotropization.
Ling-Jun Guo · Jia-Ying Xiong · Yao Ma · Yong-Liang Ma
Due to its powerful capability and high efficiency in big data analysis, machine learning has been applied in various fields. We construct a neural network platform to constrain the behaviors of the equation of state of nuclear matter with respect to the properties of nuclear matter at saturation density and the properties of neutron stars. It is found that the neural network is able to give reasonable predictions of parameter space and provide new hints into the constraints of hadron interactions. As a specific example, we take the relativistic mean field approximation in a widely accepted Walecka-type model to illustrate the feasibility and efficiency of the platform. The results show that the neural network can indeed estimate the parameters of the model at a certain precision such that both the properties of nuclear matter around saturation density and global properties of neutron stars can be saturated. The optimization of the present modularly designed neural network and extension to other effective models are straightforward.
Manjia Chen · Dawei Guan · Chongji Jiang · Junchen Pei
The speed of sound is a novel probe of equation of state and phase transitions in dense cores of neutron stars. Recently nuclear experiments extracted a surprising thick neutron skin of Pb, causing tensions to reproduce the tidal deformability in gravitational-wave observations. This work finds that exotic structures in the speed of sound with a small softening slope followed by a steep-rising peak are required to reconcile the thick neutron skin of Pb with astronomical observations of neutron stars. Furthermore, the peak of speed of sound is narrowly constrained around two times the nuclear saturation density with the thick neutron skin. Consequently early and strong first-order phase transitions are comparatively more favorable.
first authorsco-authorsvia INSPIRE