Measurement of αs from jet rates in deep inelastic scattering at HERA

Jet production in deep inelastic scattering for 120 < Q2 < 3600 GeV2 has been studied using data from an integrated luminosity of 3.2 pb−1 collected with the ZEUS detector at HERA. Jets are identified with the JADE algorithm. A cut on the angular distribution of parton emission in the γ∗-parton centre-of-mass system minimises the experimental and theoretical uncertainties in the determination of the jet rates. The jet rates, when compared to O(αs2) perturbative QCD calculations, allow a precise determination of αs(Q) in three Q2-intervals. The values are consistent with a running of ifαs(Q), as expected from QCD. Extrapolating to Q = MZ0 αs(MZ0) = 0.117 ± 0.005 (stat) −0.005+0.004 (systexp) ± 0.007 (systtheory).