Proper mean lifetime
= Proper mean lifetime
{title2=$\tau_0$}
The <mean lifetime> of an unstable <particle> measured in its <rest frame>, using elapsed <proper time>. In the <exponential decay> model, survival to <proper time> $\tau$ has <probability> $e^{-\tau/\tau_0}$. For constant <Lorentz factor> $\gamma$, <time dilation> gives laboratory <mean lifetime> $\gamma\tau_0$. A <mean lifetime> is a statistical mean, rather than a fixed decay time.