Solution
= Solution
The static <one-pion exchange> <propagator> gives a <Yukawa potential> proportional to $e^{-m_\pi cr/\hbar}/r$. Its characteristic range is therefore the <Reduced Compton wavelength>,
$$
\boxed{R\sim\frac{\hbar c}{m_\pi c^2}=\frac{197.3}{140}\,\mathrm{fm}\simeq1.4\,\mathrm{fm}}.
$$
This is an exponential falloff scale, not a sharp interaction cutoff. The ordinary <Compton wavelength> would introduce an unwanted factor $2\pi$.