Light Meson Distribution Amplitudes

Abstract

We calculated the first two moments of the light-cone distribution amplitudes for the pseudoscalar mesons ($\pi$ and $K$) and the longitudinally polarised vector mesons ($\rho$, $K^*$ and $\phi$) 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 non-perturbatively and extrapolations to the physical point were made, guided by leading order chiral perturbation theory. The main results presented are for two volumes, $16^3\times 32$ and $24^3\times 64$, with a common lattice spacing. Preliminary results for a lattice with a finer lattice spacing, $32^3\times64$, are discussed and a first look is taken at the use of twisted boundary conditions to extract distribution amplitudes.