A HIGH STATISTICS LATTICE CALCULATION OF F(B) IN THE STATIC LIMIT ON APE

We present a high statistics calculation of f(B) in the static limit. The results have been obtained by numerical simulation of quenched QCD, at beta = 6.0 on a 18(3) x 32 lattice. We compare f(B) calculated by using the Wilson and the Clover quark actions. The decay constant is obtained by studying heavy-light correlation functions of different smeared operators, on a sample of 210 gauge field configurations. We find that cubic smearings of size L(s) less-than-or-equal-to 3 or L(s) greater-than-or-equal-to 9 are bad projectors on the lightest pseudoscalar state. Combining the information coming from smearing L(s) = 5 and L(s) = 7, we have obtained f(B) = 370 +/- 40 MeV in the Clover case and f(B) = 350 +/- 40 +/- 30 MeV in the Wilson case. Our results support a large value of the pseudoscalar decay constant in the static approximation.