# Relative Mean lifetime of decays

• I
Hi there.

I want to compare the mean lifetimes of two particles which decay in a way given by two known reaction formulas, such as

##\rho^0 \rightarrow \pi^+ + \pi^-## and ##\Xi^- \rightarrow \Lambda^0 + \pi^-##

In this case it's easy: since the first one corresponds to a first interaction and the second one to a weak interaction, the first one has a shorter mean lifetime. If, for instance, both were weak, could we still compare the lifetimes (using the particles mass, for example)?