Pion Propagator in the Chiral δ Model of Nuclear Matter

摘要

Pion propagator is studied in the chiral a model at the zero temperature nucJear matter. Due to the inchyon pole of the it and a ttee approximation propagators, only the nucleon poJarization insertion loop (explicitly density dependent part and vacuum fluctuation part) am be fully included into the pion propagator. The vacuum fluctuation as a fiuictioji of n ucluon effective mass or pion external momentum (after Wick rotation) is negative foi most of t/ie cases. So the variation of nucleon effective mass is restricted to a. very limited region wham is free of pion condensation (otherwise the nucleon energy density will be complex). The effect of NN short-range correlation is ca.lcula.ted and it is very small for low momentum.