A non-perturbative calculation of the mass of the B c UKQCD Collaboration Abstract We present a calculation of the mass of the 1 S 0 pseudoscalar bc (B c) state using a non-perturbative measurement from quenched lattice QCD. We find M Bc = 6.386(9)(98)(15) GeV where the first error is statistical, the second systematic due to the quark mass ambiguities and quenching and the third the systematic...