6533b7dbfe1ef96bd127144d

RESEARCH PRODUCT

Bottom quark mass and alpha_s from the Upsilon system

subject

description

The mass of the bottom quark and the strong coupling constant alpha_s are determined from QCD moment sum rules for the Upsilon system. Two analyses are performed using both the pole mass M_b as well as the mass m_b in the $\MSb$ scheme. In the pole-mass scheme large perturbative corrections resulting from coulombic contributions have to be resummed. In the $\MSb$ scheme this can be avoided by an appropriate choice for the renormalization scale. For the bottom quark mass we obtain M_b = 4.60 +- 0.02 GeV and m_b(m_b) = 4.13 +- 0.06 GeV. Our combined result from both determinations for the strong coupling is alpha_s(M_Z) = 0.119 +- 0.008.