Imaging dynamical chiral symmetry breaking: pion wave function on the light front

Abstract

We project onto the light-front the pion's Poincare'-covariant Bethe-Salpeter wave-function, obtained using two different approximations to the kernels of QCD's Dyson-Schwinger equations. At an hadronic scale both computed results are concave and significantly broader than the asymptotic distribution amplitude, ϕ_π^{asy}(x)=6 x(1-x); e.g., the integral of ϕ_π(x)/ϕ_π^{asy}(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.

5 pages, 2 figures, 1 table