相关论文: Analysis of zero-frequency solutions of the pion d…
The solutions to the zero-sound frequency equation and pion dispersion equation are considered for the different values of the parameters of the effective particle-hole interaction. The branches of solutions, responsible for the long-wave…
In symmetrical nuclear matter the solutions of pion dispersion equation are investigated in the complex plane of the pion frequency \omega. There are three well-known branches of solutions on the physical sheet : sound, pion and isobar, at…
Results for the frequencies of zero-sound excitations in the isospin asymmetric nuclear matter are presented for the different parameters of asymmetry -1\leq\beta\leq 1. The dispersion equations are constructed within the random phase…
In isospin symmetric and asymmetric nuclear matter we study the structure functions connected with the zero sound excitations. In the simple model with Landau-Migdal quasiparticle interactions the density response $\Pi^R(\omega,k)$ of the…
In this paper the solutions of the zero-sound dispersion equation in the random phase approximation (RPA) are considered. The calculation of the damped zero-sound modes \omega_s(k) (complex frequency of excitation) in the nuclear matter is…
The recent progress on the study of the collective excitation in relativistic nuclear matter is reviewed. The collective excitation modes are derived by meson propagators in nuclear matter. The mesons we study are $\sigma, \omega, \gamma$…
A meson exchange model of the $\pi\pi$ interaction which fits free $\pi\pi$ scattering data is used to calculate the interactions of pions in nuclear matter as a function of nuclear density. Polarization of the nuclear medium by the pions…
We calculate the density-dependent spin-isospin asymmetry energy $J(k_f)$ of nuclear matter in the three-loop approximation of chiral perturbation theory. The interaction contributions to $J(k_f)$ originate from one-pion exchange, iterated…
We investigate the possibility of measuring the pion dispersion relation in nuclear matter through the anomalous coupling in the reaction \gamma - \gamma' \pi_0. It is shown that this reaction permits the study of pionic modes for…
The pion-production reactions $\pi^+ A \to \pi^+\pi^{\pm} A'$ were studied on $^{2}H$, $^{12}C$, $^{40}Ca$, and $^{208}Pb$ nuclei at an incident pion energy of $T_{\pi^{+}}$=283 MeV. Pions were detected in coincidence using the CHAOS…
We calculate the contribution of pions to the $\bar qq$-expectation value $\kappa(\rho)= <M|\bar qq|M>$ in symmetric nuclear matter. We employ exact pion propagator renormalized by nucleon-hole and isobar-hole excitations. Conventional…
Neutral pion number N0 distributions for each total number of particles in event Ntot=Nch+N0 are obtained. The scaled variance of neutral pion fluctuations, omega=D/<N0>, is measured. The fluctuations increase at Ntot >22. According to…
We estimate exclusive density and asymmetry parameter dependent dispersion relations of various charged states of pions in asymmetric nuclear matter. The possibility of matter induced mixing of $\pi^0$ with $\eta$ is clearly exposed with…
We extend a recent calculation of the nuclear energy density functional in the systematic framework of chiral perturbation theory by computing the isovector spin-orbit terms: $(\vec \nabla \rho_p- \vec \nabla \rho_n)\cdot(\vec J_p-\vec J_n)…
We evaluate the in-medium spectral functions for pions, nucleon and isobar resonances in a self consistent and covariant manner. The calculations are based on a recently developed formulation which leads to predictions in terms of the…
Nuclear reactions induced by stable and/or radioactive neutron-rich nuclei provide the opportunity to pin down the equation of state of neutron-rich matter, especially the density ($\rho$) dependence of its isospin-dependent part, i.e., the…
Within the framework of the quantum molecular dynamics transport model, the pion production and constraint of the high-density symmetry energy in heavy-ion collisions near threshold energy have been thoroughly investigated. The energy…
The directional weak decay constants of neutral pions are determined at finite temperature T, chemical potential \mu and in the presence of a constant magnetic field B. To do this, we first derive the energy dispersion relation of neutral…
The equation of state with quantum statistics corrections is used for particle number fluctuations $\omega$ of isotopically symmetric nuclear matter with interparticle van der Waals and Skyrme local density interactions. The fluctuations,…
We report variational calculations of symmetric nuclear matter and pure neutron matter, using the new Argonne v18 two-nucleon and Urbana IX three-nucleon interactions. At the equilibrium density of 0.16 fm^-3 the two-nucleon densities in…