Two-Loop Relations for Heavy-Quark Parameters in the Shape-Function Scheme

Moments of the renormalized B-meson shape function provide a natural way to define short-distance, running heavy-quark parameters such as the b-quark mass and kinetic energy. These parameters are particularly well suited for studies of inclusive decay distributions. The definitions of m_b and mu_pi^2 in this ``shape-function scheme'' are derived to two-loop order. Using previous determinations of heavy-quark parameters in other schemes, we find m_b=(4.63+-0.08) GeV and mu_\pi^2=(0.15+-0.07) GeV^2 at a reference scale of 1.5 GeV.