Four-quark scatterings in QCD III

We study the full infrared dynamics of 2+1 flavor quantum chromodynamics (QCD) with the functional renormalization group approach. We resolve self-consistently the glue dynamics as well as the dynamics of chiral symmetry breaking. The computation hosts no phenomenological parameter or external input. The only ultraviolet input parameters are the physical ones in QCD: the light and strange quark masses. They are adjusted to the physical ratios of the pion and kaon masses, divided by the pion decay constant. The results for other observables of current first-principles computations are in quantitative agreement with the physical ones. This work completes the series of papers, initiated and furthered in [; ], on dynamical chiral symmetry breaking and the emergence of mesonic bound states within the functional renormalization group. As a first application we discuss the formation of light mesonic bound states. Among other applications such as the phase structure of QCD, the current work paves the way for studying QCD parton distribution functions within the functional renormalization group approach to first-principles QCD.