Reanalysis of the four-quark operators relevant to the Λb lifetime from the QCD sum rule -: art. no. 054004

The Lambda(b) matrix element of the four-quark operator relevant to its lifetime is reanalyzed by the QCD sum rule method. The new ingredients introduced are that (1) more vacuum condensates are considered, (2) a different quark-hadron duality is adopted, and (3) the possible deviation from the vacuum saturation assumption for the four quark condensates is considered. With kappa(1) = 4 the related hadronic parameter r is calculated to be (3.6 +/- 0.9), and the lifetime ratio tau(Lambda(b))/tau(B-0) = (0.83 +/- 0.04), which is consistent with experimental data.