Distribution amplitudes and decay constants for $(π,K,ρ,K^*)$ mesons in light-front quark model

Abstract

We present a calculation of the quark distribution amplitudes(DAs), the Gegenbauer moments, and decay constants for $π,ρ,K$ and $K^*$ mesons using the light-front quark model. While the quark DA for $π$ is somewhat broader than the asymptotic one, that for $ρ$ meson is very close to the asymptotic one. The quark DAs for $K$ and $K^*$ show asymmetric form due to the flavor SU(3)-symmetry breaking effect. The decay constants for the transversely polarized $ρ$ and $K^*$ mesons($f^T_ρ$ and $f^T_{K^*}$) as well as the longitudinally polarized ones($f_ρ$ and $f_{K^*}$) are also obtained. Our averaged values for $f^T_V/f_V$, i.e. $(f^T_ρ/f_ρ)_{\rm av}=0.78$ and $(f^T_{K^*}/f_{K^*})_{\rm av}=0.84$, are found to be consistent with other model predictions. Especially, our results for the decay constants are in a good agreement with the SU(6) symmetry relation, $f^T_{ρ(K^*)}=(f_{π(K)}+f_{ρ(K^*)})/2$.

12 pages, 6figures