Meson Form-factors and Wave-functions with Wilson fermions

TL;DR

This paper presents lattice QCD calculations of meson form-factors and Bethe-Salpeter amplitudes using Wilson fermions, revealing insights into meson structure and polarization states.

Contribution

It provides new lattice QCD results for semi-leptonic form-factors and Bethe-Salpeter amplitudes, including the discovery of a lighter effective mass and higher angular momentum states in the rho meson.

Findings

Form-factor data aligns with previous studies.

Bethe-Salpeter amplitudes decay exponentially with a lighter effective mass.

Evidence of a measurable l=2 state in the rho meson.

Abstract

Results for semi-leptonic form-factors for processes like $D \to K l \nu$ and the Bethe-Salpeter amplitudes (BSA) for pion and rho mesons are presented. The form-factor data is consistent with previous calculations. We find that the long distance fall-off of BSA for both $\pi$ and $\rho$ is very well fit by an exponential, but surprisingly the effective mass governing this fall-off is lighter than the pion's. Lastly, by studying the dependence of $\rho$ polarization on separation direction we show that there is a measureable $l=2$ state in addition to $l=0$ in the BSA for the rho. (Talk presented by R. Gupta at LATTICE92. Latex needs macro package espcrc2.sty)