Abstract
The $1/m_b$ corrections in the calculations of inclusive decayrates are explored by PQCD technique. Since resummation for theinitial heavy hadron has been shown not violating the duality, thepossible mechanism responsible for the breakdown of the localduality that we proposed arises from threshold resummationassociated with final-state particles. By manipulating thekinematical gaps within quark-frame and hadron-frameconsiderations, the $1/m_b$ corrections come out in the inclusivedecay rates. One of the sources of the $1/m_b$ corrections isproved to be originated from renormalon effect. The numericalresults of $B_{sL}$, $n_c$, $r_{c\tau \bar\nu}$, $r_{c\bar cs}$,$r_{c\bar ud}$, $\tau(B_u)$, $\tau(B_s)$, $\tau(B_d)$ and$\tau(\Lambda_b)$ without $O(\alpha_s)$ corrections are obtained.