The Rare Decays $\text{piee}$, $\text{etaee}$ and \etamumu$ in Chiral Perturbation Theory

Abstract

We calculate the decay rates for $\text{piee}$, $\text{etaee}$ and $\text{etamumu}$ in chiral perturbation theory. The linear combination of counterterms necessary to render these amplitudes finite is fixed by the recently measured branching fraction for $\text{etamumu}$. We find $\text{Br}(\text{piee})=7\pm 1\times 10^{-8}$ and $\text{Br}(\text{etaee})=5\pm 1\times 10^{-9}$.

Comments: (6 pages, 1 figure available on request, uses harvmac.tex), UCSD/PTH 92-23, CALT-68-1803