Precision Measurements of alphas at HERA

Abstract

The precision measurements of the strong coupling constant, alphas, and its energy-scale dependence carried out at HERA by the H1 and ZEUS Collaborations are reviewed. An average value of alphas(Mz) = 0.1186 +- 0.0011 (exp.) +- 0.0050 (th.) is obtained from these measurements. The combined HERA determinations of the energy-scale dependence of alphas clearly show the running of alphas from jet data alone and are in agreement with the running of the coupling as predicted by QCD.