Speaker
Description
In this talk, I would like to discuss recent progress in the construction of functional renormalization group (fRG) approach to first-principles QCD within the four-quark scatterings, and its application to the calculation of quasi-parton distribution amplitudes (PDA) for pions. We investigate dynamical chiral symmetry breaking and the emergence of mesonic bound states from the infrared dynamics of four-quark scatterings. The flows of Fierz-complete four-quark interaction are integrated together with the flow of the quark two-point function. This system can be understood as the fRG analogues of the complete Bethe-Salpeter equations and quark gap equation. A three-momentum channel approximation for the Fierz-complete four-quark vertices is used. We have computed the pion pole mass, pion decay constant, Bethe-Salpeter amplitudes, the quark mass function and wave function. With the Bethe-Salpeter amplitudes and the quark mass function, One is able to compute the pion valence-quark quasi-PDA.
