Bottomonium from NRQCD with Dynamical Wilson Fermions

We present results for the bb̄ spectrum obtained using an O(Mbv )-correct non-relativistic lattice QCD action. Propagators are evaluated on SESAM’s three sets of dynamical gauge configurations generated with two flavours of Wilson fermions at β = 5.6. Compared to a quenched simulation at equivalent lattice spacing we find better agreement of our dynamical data with experimental results in the spin-independent sector but observe no unquenching effects in hyperfine-splittings. To pin down the systematic errors we have also compared quenched results in different “tadpole” schemes and used a lower order action.