On (πμ) atoms produced in K0L decay

The branching ratio for producing (πμ) atoms in K⁰_L decay is calculated. Using the approximate solution of the Bethe-Salpeter equation for the (πμ) atom, the S-matrix element of this process is written in a more precise form than that obtained intuitively. Furthermore, all corrections of $\text{O}\text{(α) (α =}\text{e}{}^2\text{4π}\text{)}$ are considered. As a result, the branching ratio may be used to determine the form factor ζ = f_?(0)/f₊(0) of K⁰_L.