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. 
P.Yu.Kulikov, I.M.Narodetskii, A.I.Onischenko (Institute for   Theoretical and Experimental Physics, Moscow)