Heavy quark spectroscopy and matrix elements: A lattice study using the static approximation

We present results of a lattice analysis of the B parameter B-B, the decay constant f(B), and several mass splittings using the static approximation. Results were obtained for 60 quenched gauge configurations computed at beta=6.2 on a lattice size of 24(3) X 48. Light quark propagators were calculated using the O(a)-improved Sheikholeslami-Wohlert action. We find B-B(static)(m(b))=0.69(-4)(+3)(stat)(-1)(+2)(syst), corresponding to B-B(static)=1.02(-6 -2)(+5 +3), f(B)(static)=266(-20 -27)(+18 +28) MeV, and f(Bs)(2)B(Bs)/f(B)(2)B(B)=1.34(-8 -3)(+9 +5), where a variational fitting technique was used to extract f(B)(static). For the mass splittings we obtain M(Bs)-M(Bd)=87(-12 -12)(+15 +6) MeV, M(Lambda b)-M(Bd) =420(-90 -30)(+100 +30) MeV, and M(B*)(2)-M(B*)(2)=0.281(-16 -37)(+15 +40) GeV2. We compare different smearing techniques intended to improve the signal/noise ratio. From a detailed assessment of systematic effects, we conclude that the main systematic uncertainties are associated with the renormalization constants relating a lattice matrix element to its continuum counterpart. The dependence of our findings on lattice artifacts is to be investigated in the future.