Matrix Elements of Four-quark Operators Relevant to Lifetime Difference   \Delta \Gamma_{B_s} from QCD Sum Rules
  We extract the matrix elements of four quark operators O_{L,S} relevant to the B_s and \bar B_s life time difference from QCD sum rules. We find the vacuum saturation approximation works reasonably well, i.e., within 10%. We discuss the implications of our results and compare them with the recent lattice QCD determination. 
C.-S. Huang, Ailin Zhang and Shi-Lin Zhu