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

D. Decamp, B. Deschizeaux, C. Goy, J. P. Lees, M. N. Minard, R. Alemany, J. M. Crespo, M. Delfino, E. Fernandez, V. Gaitan, Ll Garrido, P. Mato, R. Miquel, Ll M. Mir, S. Orteu, A. Pacheco, J. A. Perlas, E. Tubau, M. G. Catanesi, D. CreanzaM. de Palma, A. Farilla, G. Iaselli, G. Maggi, M. Maggi, S. Natali, S. Nuzzo, M. Quattromini, A. Ranieri, G. Raso, F. Romano, F. Ruggieri, G. Selvaggi, L. Silvestris, P. Tempesta, G. Zito, Y. Gao, H. Hu, D. Huang, X. Huang, J. Lin, J. Lou, C. Qiao, T. Ruan, T. Wang, Y. Xie, D. Xu, R. Xu, J. Zhang, W. Zhao, H. Albrecht, W. B. Atwood, F. Bird, E. Blucher, G. Bonvicini, F. Bossi, D. Brown, T. H. Burnett, H. Drevermann, F. Dydak, R. W. Forty, C. Grab, R. Hagelberg, S. Haywood, B. Jost, M. Kasemann, G. Kellner, J. Knobloch, A. Lacourt, I. Lehraus, T. Lohse, D. Lüke, A. Marchioro, M. Martinez, J. May, S. Menary, A. Minten, A. Miotto, J. Nash, P. Palazzi, F. Ranjard, G. Redlinger, A. Roth, J. Rothberg, H. Rotscheidt, W. von Rüden, R. St.Denis, D. Schlatter, M. Takashima, M. Talby, W. Tejessy, H. Wachsmuth, S. Wasserbaech, S. Wheeler, W. Wiedenmann, W. Witzeling, J. Wotschack, Z. Ajaltouni, M. Bardadin-Otwinowska, A. Falvard

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46 Citations (Scopus)


Using 106 000 hadronic events obtained with the ALEPH detector at LEP at energies close to the Z resonance peak, the strong coupling constant αs 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, Ycut, before these variables are computed. The combined result from all shape variables of pre-clustered events is αs(MZ2 = 0.117±0.005 for a renormalization scale μ= 1 2 MZ. For μ values between MZ and the b-quark mass, the result changes by -0.009+0.006. © 1991.
Original languageEnglish
Pages (from-to)479-491
JournalPhysics Letters B
Issue number3-4
Publication statusPublished - 28 Mar 1991


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