摘要
Based on the quark propagator derived in the instanton dilute liquid approximation, the quark condensate susceptibilities have been calculated at the mean-field level in a nonperturbative QCD model. The numerical results are compatible with the values obtained within other nonperturbative approaches. The calculated masses and decay constants of π and σ mesons are close to the experimental values. These results show that the instanton medium might be a good approximation of the QCD vacuum.
基金
国家自然科学基金，南京大学校科研和教改项目
