Effective Meson mass in nuclear matter based on dispersion equation including NN-, Delta(-)Delta N excitations

摘要

Effective meson masses of sigma, omega, rho and pi in nuclear matter are calculated from the meson self-energy of the particle-antiparticle excitations. Instead of the traditional renormalization, the dispersion relation method is used to calculate the real part from the finite imaginary part, since the tenser coupling of the pion and p meson is not renormalized in the usual sense. In this paper, we show the effects from antidelta-nucleon and deltaantinucleon excitations in pi meson mass beside nucleon-anti nucleon excitation. It is also shown that agreement is obtained on the w meson mass predicted by the subtraction method and p meson mass by the QCD sum rule method. It is concluded that the dispersion equation method leads to the fact that all the meson mass decreases as the baryon density increases, and it supports the chiral symmetry restoration.