Lifetime measurements in $b$-hadron decays at LHCb
  Precision lifetime measurements of $b$-flavoured hadrons are an important test of the validity of the theoretical tool used to determine $b$-hadrons observables, the Heavy Quark Expansion. Recent measurements of the $B^+$, $\Lambda^0_b$, $\Xi^-_b$, $\Xi^0_b$ and $\Omega^-_b$ hadrons lifetimes are reported. Moreover, several $B^0$ and $B^0_s$ effective lifetime measurements are discussed, as well as a measurement of the decay width difference in the $B^0$ system, $\Delta \Gamma_d$. All the measurements have been performed using $pp$ collision data collected with the LHCb detector. 
Francesca Dordei
hep-ex