NN¯,Δ¯N,ΔN

Abstract

The particle -hole and delta -hole excitations are well known elementary excitation modes for pion propagator in nuclear matter. But, the excitation also involves antiparticles, namely, nucleon-antinucleon, antidelta-nucleon and delta-antinucleon excitations.These are important for high energy-momentum as well, and not studied before. In this paper, we give both the formulae and the numerical calculations for the real and the imaginary parts of these excitations.