Mean lifetime (physics)
= Mean lifetime
{disambiguate=physics}
{title2=$\tau=\hbar/\Gamma$}
= Mean lifetime
{synonym}
For an unstable <particle> undergoing <exponential decay> in its <rest frame>, the decay waiting time has an <exponential distribution> with <mean> $\tau$. Its probability of surviving to time $t\geq0$ is $e^{-t/\tau}$, and its total <decay width> is $\Gamma=\hbar/\tau$. In units $\hbar=1$, $\tau=1/\Gamma$.