Hadronic decays from the lattice

Abstract

We discuss strategies to determine hadronic decay couplings from lattice studies. As an application, we explore the decay of a vector meson to two pseudoscalar mesons with $N_f=2$ flavours of sea quark. Although we are working with quark masses that do not allow a physical decay, we show how the transition rate can be evaluated from the amplitude for $\ddot{I}\to \ddot{I}€\ddot{I}€$ and from the annihilation component of $\ddot{I}€\ddot{I}€\to \ddot{I}€\ddot{I}€$. We explore the decay amplitude for two different pion momenta and find consistent results. The coupling strength we find is in agreement with experiment. We also find evidence for a shift in the $\ddot{I}$ mass caused by mixing with two pion states.

Proc. Latt03 (spectrum), 3 pages, 4 figs