Precision determination of alpha_S(m_Z) from thrust data
Michael Fickinger (University of Arizona)

I will present an extraction of the strong coupling constant, alpha_S(m_Z), from thrust data using Effective Field Theory techniques. Our calculation yields one of the most precise measurements of alpha_S(m_Z) to date. We perform one fit in the tail region of the thrust distribution and a second fit for the first moment of the thrust distribution. Both fits are simultaneous two parameter fit to all available data at center-of-mass energies Q = 35 GeV to 207 GeV. We find alpha_S(m_Z) = 0.1135 +- (0.0002)expt +- (0.0005)hadr +- (0.0009)pert for the tail fit, and alpha_S(m_Z) = 0.1140 +- (0.0004)exp +- (0.0013)hadr +- (0.0007)pert for the first moment fit. The displayed 1-sigma errors are the total experimental uncertainty, the hadronization uncertainty, and the perturbative theory uncertainty, respectively.