
In this work, we find the expressions of continuum HQET fourfermion operators in terms of lattice operators in perturbation theory. To do so, we calculate the oneloop continuumlattice HQET matching for the complete basis of Delta B = 2 and Delta B = 0 operators (excluding penguin diagrams), extending and completing previous studies. We have also corrected some errors in previous evaluations of the matching for the operator OLL. Our results are relevant to the lattice computation of the values of unknown hadronic matrix elements which enter in many very important theoretical predictions in Bmeson phenomenology: B0(B) over bar(0) mixing, tau(B) and tau(B), lifetimes, SUSY effects in Delta B = 2 transitions and the Bs width difference Delta Gamma(Bs). We have reanalyzed our lattice data for the BB parameter of the B0(B) over bar(0) mixing on 600 lattices of size 24(3) x 40 at beta = 6.0 computed with the SWClover and HQET lattice actions. We have used the correct latticecontinuum matching factors and boosted perturbation theory with tadpole improved heavylight operators to reduce the systematic error in the evaluation of the renormalization constants. Our best estimate of the renormalization scale independent Bparameter is (B) over cap(B) = 1.29 +/ 0.08 +/ 0.06, where the first error is statistical and the second is systematic coming from the uncertainty in the determination of the renormalization constants, Our result is in good agreement with previous results obtained by extrapolating Wilson data, As a byproduct, we also obtain the complete oneloop anomalous dimension matrix for fourfermion operators in the HQET.
