Measurement of alpha-s from the structure of particle clusters produced in hadronic Z decays

Collaboration
Dec, 1990
13 pages
Published in:
  • Phys.Lett.B 257 (1991) 479-491
  • Published: 1991
Report number:
  • CERN-PPE-90-196
Experiments:

Citations per year

1991200020092018202505101520
Abstract: (Elsevier)
Using 106 000 hadronic events obtained with the ALEPH detector at LEP at energies close to the Z resonance peak, the strong coupling constant α s is measured by an analysis of energy-energy correlations (EEC) and the global event shape variables thrust, C -parameter and oblateness. It is shown that the theoretical uncertainties can be significantly reduced if the final state particles are first combined in clusters using a minimum scaled invariant mass cut, Y cut , before these variables are computed. The combined result from all shape variables of pre-clustered events is α s ( M Z 2 = 0.117±0.005 for a renormalization scale μ= 1 2 M Z . For μ values between M Z and the b-quark mass, the result changes by −0.009 +0.006 .
  • electron positron: colliding beams
  • colliding beams: electron positron
  • electron positron: annihilation
  • annihilation: electron positron
  • Z0: electroproduction
  • electroproduction: Z0
  • Z0: nonleptonic decay
  • nonleptonic decay: Z0
  • strong interaction: coupling constant
  • coupling constant: strong interaction