Leipzig 2002 – wissenschaftliches Programm
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T: Teilchenphysik
T 203: QCD II
T 203.3: Vortrag
Montag, 18. März 2002, 16:45–17:00, HS 10
First determinations of αS at √s= 14 to 44 GeV using resummed calculations — •Pedro A. Movilla Fernández, S. Bethke, O. Biebel, M. Blumenstengel, S. Kluth, C. Pahl, J. Schieck, and M. Tönnesmann — Max-Planck-Institut für Physik, München
Tests of Quantum Chromodynamics (QCD) substantially benefit from e+e− annihilation data far below the Z peak. Recently, data collected by the JADE experiment at PETRA (1979-1986) became available for state-of-the-art studies of perturbative and non-perturbative aspects of QCD at √s= 14 to 44 GeV [1] thus representing an important counterpart to LEP w.r.t. the Z peak.
Our first measurements of the strong coupling constant αS from event shape observables at 14 GeV provide stringent tests of the energy evolution of QCD using e+e− data. It turns out that the resummed NLO calculations are applicable at the lowest energies of the e+e− continuum although non-perturbative contributions become very important.
At 14 GeV, where hadronization effects are crucial, data have been used to assess the performance of various Monte Carlo generators (e.g. Pythia or Herwig) tuned to LEP data, and to investigate the power correction approach to describe such non-perturbative effects.
[1] see e.g. hep-ex/0105059, hep-ex/0106066, hep-ex/0012044