Parton Distribution Amplitudes

Abstract

We calculated the first two moments of the light-cone distribution amplitudes for the pseudoscalar mesons (π and K) and the longitudinally polarised vector mesons (ρ, K * and φ ) as part of the UKQCD and RBC collaborations' N f = 2 + 1 domain-wall fermion phenomenology programme. These quantities were obtained with a good precision and, in particular, the expected effects of SU(3)-flavour symmetry breaking were observed. Operators were renormalised nonperturbatively and extrapolations to the physical point were made, guided by leading order chiral perturbation theory. The main results presented are for two volumes, 16 3 ×32 and 24 3 ×64, with a common lattice spacing. Preliminary results for a lattice with a finer lattice spacing, 32 3 × 64, are discussed and a first look is taken at the use of twisted boundary conditions to extract distribution amplitudes.