The Lambda_b lifetime in the light front quark model

The enhancement of the Lambda_b decay width relative to B decay one due to the difference of Fermi motion effects in Lambda_b and B is calculated in the light--front quark model with the simplifying assumption that Lambda_b consists of the heavy quark and light scalar diquark. In order to explain the large deviation from unity in the experimental result for tau(Lambda_b)/tau(B), it is necessary that diquark be light and the ratio of the squares of the Lambda_b and B wave functions at the origin be \le 1.Comment: final journal version to appear in JETP Letter

The heavy baryons in the nonperturbative string approach

We present some piloting calculations of the short-range correlation coefficients for the light and heavy baryons and masses of the doubly heavy baryons $\Xi_{QQ'}$ and $\Omega_{QQ'}$ ($Q,Q'=c,b$) in the framework of the simple approximation within the nonperturbative QCD approach.Comment: 21 pages; to appear in Phys. Atom. Nuc