Using 106000 hadronic events obtained with the ALEPH detector at LEP at energies close to the Z resonance peak, the strong coupling constant alfa_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 alfa_s(( M_Z)^2)=0.117 +/- 0.005 for a renormalization scale mu=1/2M_Z. For mu values between M_Z and the b-quark mass, the result changes by -0.009 +0.006.

D., D., B., D., C., G., J., L., M., M., R., A., et al. (1991). Measurement of alfa_s from the structure of particle clusters produced in hadronic Z decays. PHYSICS LETTERS. SECTION B, 257(3-4), 479-491 [10.1016/0370-2693(91)91926-M].

Measurement of alfa_s from the structure of particle clusters produced in hadronic Z decays

BOTTIGLI, UBALDO;CIOCCI, MARIA AGNESE;MARROCCHESI, PIER SIMONE;
1991-01-01

Abstract

Using 106000 hadronic events obtained with the ALEPH detector at LEP at energies close to the Z resonance peak, the strong coupling constant alfa_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 alfa_s(( M_Z)^2)=0.117 +/- 0.005 for a renormalization scale mu=1/2M_Z. For mu values between M_Z and the b-quark mass, the result changes by -0.009 +0.006.
1991
D., D., B., D., C., G., J., L., M., M., R., A., et al. (1991). Measurement of alfa_s from the structure of particle clusters produced in hadronic Z decays. PHYSICS LETTERS. SECTION B, 257(3-4), 479-491 [10.1016/0370-2693(91)91926-M].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11365/35846
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