Possible scenario of dynamical chiral symmetry breaking in the instanton liquid

Using simulations of the interacting instanton liquid model (IILM) with the flavor SU(3) symmetric quarks, we compute the free energy densify of the QCD vacuum as a function of the quark condensate. We then compute the second derivative of the free energy density with respect to the quark condensate at the origin. This computation allows us to investigate whether chiral symmetry breaking in the IILM occurs in an anomaly-driven manner. This chiral symmetry breaking pattern has been proposed in a previous study as a mechanism linking the QCD vacuum structure to meson properties, such as the mass of the sigma meson. We also perform quenched simulations, in which no dynamical quarks interact with instantons. Comparing these results with the full calculations provides a better understanding of chiral symmetry breaking patterns in the IILM. We find that in the full IILM, chiral symmetry is dynamically broken in anomaly-driven manner, whereas in the quenched IILM, it is broken through the ordinary mechanism. Based on these results, we suggest that chiral symmetry breaking in real QCD may also occur in an anomaly-driven manner. Consequently, in phenomena where chiral symmetry breaking plays a crucial role, the anomalous effect may also have a significant impact.