DSE Perspective on QCD Modeling, Distribution Amplitudes, and Form Factors

作者：Tandy Peter C^*

来源：Few-Body Systems, 2014, 55(5-7): 357-365.

DOI：10.1007/s00601-014-0899-y

We describe results for the pion distribution amplitude (PDA) at the non-perturbative scale mu = 2 GeV by projecting the Poincar-covariant Bethe-Salpeterwave-function onto the light-front and use it to investigate the ultraviolet behavior of the electromagnetic form factor, F-pi (Q(2)), on the entire domain of spacelike Q(2). The significant dilation of this PDA compared to the known asymptotic PDA is a signature of dynamical chiral symmetry breaking on the light front. We investigate the transition region of Q(2) where non-perturbative behavior of constituent-like quarks gives way to the partonic-like behavior of quantum chromodynamics (QCD). The non-perturbative approach is based on the Dyson-Schwinger equation (DSE) framework for continuum investigations in QCD. The leading-order, leading-twist perturbative QCD result for Q(2)F(pi) (Q(2)) underestimates the new DSE computation by just 15% on Q(2) greater than or similar to 8 GeV2, in stark contrast with the result obtained using the asymptotic PDA.

• 出版日期2014-6