Imaging Dynamical Chiral-Symmetry Breaking: Pion Wave Function on the Light Front

We project onto the light front the pion's Poincare-covariant Bethe-Salpeter wave function obtained using two different approximations to the kernels of quantum chromodynamics' Dyson-Schwinger equations. At an hadronic scale, both computed results are concave and significantly broader than the asymptotic distribution amplitude, phi(asy)(pi) (x) = 6x(1 - x); e.g., the integral of phi(pi)(x)/phi(asy)(pi)(x) is 1.8 using the simplest kernel and 1.5 with the more sophisticated kernel. Independent of the kernels, the emergent phenomenon of dynamical chiral-symmetry breaking is responsible for hardening the amplitude. DOI: 10.1103/PhysRevLett.110.132001