Inclusive Charmed-Baryon Decays and Lifetimes

We have quantitatively reanalyzed the inclusive charmed-baryon decays. New ingredients are the Voloshin preasymptotic effects in semileptonic decays and the Cabibbo-subleading contributions to both semileptonic and nonleptonic decays. It has been found that the Cabbibo-subleading Voloshin contribution essentially improves the theoretical semileptonic branching ratio of $\Lambda_c^{+}$, in agreement with experiment. The semileptonic branching ratios for $\Xi_c^{+}$ and $\Omega_c^{0}$ are found to be large, i.e., of the order of 20%. The lifetimes hierarchy is in a good qualitative and even quantitative agreement with experiment except for the $\Xi_c^{+}$ lifetime, which is somewhat smaller than the experimental value. Future measurements, especially measurements of the semileptonic branching ratios for $\Omega_c^{0}$, $\Xi_c^{+}$ and $\Xi_c^{0}$ should be decisive for the check of this approach.Comment: 13 pages, Latex, 3 figures included, shortened version, to appear in Z.Phys.

Preasymptotic effects in beauty decays

Large preasymptotic effects in beauty decays have been found using heavy-quark and SU(3) symmetry, as well as experimental data on charmed hyperons. Contrary to rather uniform beauty-meson lifetimes, a much larger spread of beauty-baryon lifetimes is predicted. However, it is highly unlikely that, theoretically, the $\tau(\Lambda_b)/\tau(B_d^0)$ ratio, which at present deviates more than $1\sigma$ from the experimental result, can be lowered below 0.9.Comment: 6 pages, talk given by B. Melic at The 3rd International Conference on B Physics and CP Violation, Taipei, Taiwan, December 3-7, 1999, to appear in the Proceedings, two figures adde