A high statistics lattice calculation of the b-meson binding energy

We present a high statistics lattice calculation of the B--meson binding energy \overline{\Lambda} of the heavy--quark inside the pseudoscalar B--meson. Our numerical results have been obtained from several independent numerical simulations at \beta=6.0, 6.2 and 6.4 and using, for the meson correlators, the results obtained by the APE group at the same values of \beta. Our best estimate, obtained by combining results at different values of \beta, is \overline{\Lambda}=180^{+30}_{-20} MeV. For the \overline{MS} running mass, we obtain \overline{m}_{b}(\overline{m}_{b})=4.15 \pm 0.05 \pm 0.20 GeV, in reasonable agreement with previous determinations. The systematic error is the truncation of the perturbative series in the matching condition of the relevant operator of the Heavy Quark Effective Theory.