Light Meson Distribution Amplitudes

TL;DR

This paper computes the first two moments of light-cone distribution amplitudes for various mesons using lattice QCD, observing SU(3) symmetry breaking effects with high precision and exploring new techniques like twisted boundary conditions.

Contribution

It provides the first precise lattice QCD calculations of meson distribution amplitude moments, including non-perturbative renormalization and analysis of symmetry breaking effects.

Findings

Observed SU(3) flavor symmetry breaking effects.

Achieved good precision in moments calculation.

Explored twisted boundary conditions for amplitude extraction.

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.