αs at Zinnowitz 2004

The Determination of αS at Hadron Colliders

Hadron colliders offer a unique opportunity to test perturbative QCD because, rather than producing events at a specific beam energy, the dynamics of the hard scattering is probed simultaneously at a wide range of momentum transfers. This makes the determination of αS and the parton density functions (PDF) at hadron colliders particularly interesting. In this paper we restrict ourselves to extr...

Jet-Studies and αs-determinations at HERA ∗.

Recent results from the H1 and ZEUS Collaborations on inclusive single and multiple jet production in the neutral current deep inelastic scattering of electrons/positrons on protons and the high energy photoproduction on protons at HERA are reported. The results are compared with NLO QCD calculations and have been used to determine the strong interaction coupling constant αs.

Compatibility of αs(Mτ) with αs(MZ)

Measurement of αS in Radiative Hadronic Events at OPAL

Hadronic final states with a hard isolated photon are studied using data taken at centre-of-mass energies around MZ with the OPAL detector at LEP. The strong coupling αS is extracted by fitting event shape variables for the reduced centre-of-mass energies ranging from 20 GeV to 80 GeV, and the energy dependence of αS is studied. Combining all the values using different event shape variables and...

Jet Cross-Sections and αS in DIS at HERA

Measurements of inclusive-jet and dijet cross-sections in high-Q deep-inelastic scattering are presented together with a short overview of extractions of the strong coupling parameter αS from jets. The data samples used were collected with the ZEUS detector at HERA-1 and HERA-2. The measured distributions are compared to QCD calculations in next-to-leading order which describe the data very wel...