Data from e+e- annihilation into hadrons, taken with the ALEPH detector at the Z resonance, are analyzed. The four-jet rate is studied as a function of the resolution parameter and compared to next-to-leading order calculations combined with resummation of large logarithms. Angular correlations in four-jet events are measured and compared to next-to-leading order QCD predictions. With these observables two different measurements are performed. In a first analysis the strong coupling constant is measured from the four-jet rate yielding alpha_s(M_ Z}) = 0.1170 \pm 0.0001(stat) \pm 0.0014(sys) In a second measurement the strong coupling constant and the \textsc{QCD} colour factors are determined simultaneously from a fit to the four-jet rate and the four-jet angular correlations, giving alpha_s(M_ Z) = 0.119 \pm 0.006(stat) \pm 0.026 (sys) C_A = 2.93 \pm 0.14(stat) \pm 0.58 (sys) C_F} = 1.35 \pm 0.07 (stat) \pm 0.26 (sys) in good agreement with the expectation from QCD
Measurements of the strong coupling constant and the QCD colour factors using four-jet observables from hadronic Z decays / A. Heister, S. Schael, R. Barate, I. De Bonis, D. Decamp, C. Goy, J.P. Lees, E. Merle, M.N. Minard, B. Pietrzyk, G. Boix, S. Bravo, M.P. Casado, M. Chmeissani, J.M. Crespo, E. Fernandez, M. Fernandez-Bosman, L. Garrido, E. Grauges-Pous, M. Martinez, G. Merino, R. Miquel, L.M. Mir, A. Pacheco, H. Ruiz, A. Colaleo, D. Creanza, M. De Palma, G. Iaselli, G. Maggi, M. Maggi, S. Nuzzo, A. Ranieri, G. Raso, F. Ruggieri, G. Selvaggi, L. Silvestris, P. Tempesta, A. Tricomi, G. Zito, X. Huang, J. Lin, Q. Ouyang, T. Wang, Y. Xie, R. Xu, S. Xue, J. Zhang, L. Zhang, W. Zhao, D. Abbaneo, P. Azzurri, O.L. Buchmuller, M. Cattaneo, F. Cerutti, B. Clerbaux, H. Drevermann, R.W. Forty, M. Frank, F. Gianotti, T.C. Greening, J.B. Hansen, J. Harvey, D.E. Hutchcroft, P. Janot, B. Jost, M. Kado, P. Mato, A. Moutoussi, F. Ranjard, L. Rolandi, W.D. Schlatter, O. Schneider, G. Sguazzoni, W. Tejessy, F. Teubert, A. Valassi, I. Videau, J. Ward, F. Badaud, A. Falvard, P. Gay, P. Henrard, J. Jousset, B. Michel, S. Monteil, J. C. Montret, D. Pallin, P. Perret, J.D. Hansen, J.R. Hansen, P.H. Hansen, B.S. Nilsson, A. Kyriakis, C. Markou, E. Simopoulou, A. Vayaki, K. Zachariadou, A. Blondel, G.R. Bonneaud, J.C. Brient, A. Rouge', M. Rumpf, M. Swynghedauw, M. Verderi, H.L. Videau, V. Ciulli, E. Focardi, G. Parrini, A. Antonelli, M. Antonelli, G. Bencivenni, F. Bossi, P. Campana, G. Capon, V. Chiarella, P. Laurelli, G. Mannocchi, F. Murtas, G.P. Murtas, L. Passalacqua, M. Pepe'-Altarelli, A. Halley, J.G. Lynch, P. Negus, V. O'Shea, C. Raine, A.S. Thompson, S.R. Wasserbaech, R.J. Cavanaugh, S. Dhamotharan, C. Geweniger, P. Hanke, V. Hepp, E.E. Kluge, A. Putzer, H. Stenzel, K. Tittel, M. Wunsch, R. Beuselinck, D. M. Binnie, W. Cameron, P.J. Dornan, M. Girone, N. Marinelli, J.K. Sedgbeer, J.C. Thompson, V. M. Ghete, P. Girtler, E. Kneringer, D. Kuhn, G. Rudolph, E. Bouhova-Thacker, C.K. Bowdery, A.J. Finch, F. Foster, G. Hughes, R.W.L. Jones, M.R. Pearson, N.A. Robertson, K. Jakobs, K. Kleinknecht, G. Quast, B. Renk, H.G. Sander, H. Wachsmuth, C. Zeitnitz, A. Bonissent, P. Coyle, O. Leroy, P. Payre, D. Rousseau, M. Talby, F. Ragusa, A. David, H. Dietl, G. Ganis, K. Huttmann, G. Lutjens, W. Manner, H.G. Moser, R. Settles, W. Wiedenmann, G. Wolf, J. Boucrot, O. Callot, M. Davier, L. Duflot, J.F. Grivaz, P. Heusse, A. Jacholkowska, J. Lefrancois, J.J. Veillet, C. Yuan, G. Bagliesi, T. Boccali, L. Foa', A. Giammanco, A. Giassi, F. Ligabue, A. Messineo, F. Palla, G. Sanguinetti, A. Sciaba', P. Spagnolo, R. Tenchini, A. Venturi, P.G. Verdini, Z. Xie, G.A. Blair, G. Cowan, M.G. Green, T. Medcalf, A. Misiejuk, J.A. Strong, P. Teixeira-Dias, R.W. Clifft, T.R. Edgecock, P.R. Norton, I.R. Tomalin, B. Bloch-Devaux, P. Colas, S. Emery, W. Kozanecki, E. Lancon, M.C. Lemaire, E. Locci, P. Perez, J. Rander, J.F. Renardy, A. Roussarie, J.P. Schuller, J. Schwindling, A. Trabelsi, B. Vallage, N.P. Konstantinidis, A.M. Litke, G. Taylor, C.N. Booth, S.L. Cartwright, F. Combley, M.H. Lehto, L.F. Thompson, K. Affholderbach, A. Bohrer, S. Brandt, C. Grupen, A. Ngac, G. Prange, U. Sieler, G. Giannini, J.E. Rothberg, S.R. Armstrong, K. Berkelman, K. Cranmer, D.P.S. Ferguson, Y. Gao, S. Gonzalez, O.J. Hayes, H. Hu, S. Jin, J. Kile, P. A. McNamara, J. Nielsen, Y. B. Pan, J.H. Von Wimmersperg-Toller, J. Wu, Sau Lan Wu, X. Wu, G. Zobernig, G. Dissertori. - In: THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS. - ISSN 1434-6044. - 27:1(2003), pp. 1-17. [10.1140/epjc/s2002-01114-2]
Measurements of the strong coupling constant and the QCD colour factors using four-jet observables from hadronic Z decays
F. Ragusa;
2003
Abstract
Data from e+e- annihilation into hadrons, taken with the ALEPH detector at the Z resonance, are analyzed. The four-jet rate is studied as a function of the resolution parameter and compared to next-to-leading order calculations combined with resummation of large logarithms. Angular correlations in four-jet events are measured and compared to next-to-leading order QCD predictions. With these observables two different measurements are performed. In a first analysis the strong coupling constant is measured from the four-jet rate yielding alpha_s(M_ Z}) = 0.1170 \pm 0.0001(stat) \pm 0.0014(sys) In a second measurement the strong coupling constant and the \textsc{QCD} colour factors are determined simultaneously from a fit to the four-jet rate and the four-jet angular correlations, giving alpha_s(M_ Z) = 0.119 \pm 0.006(stat) \pm 0.026 (sys) C_A = 2.93 \pm 0.14(stat) \pm 0.58 (sys) C_F} = 1.35 \pm 0.07 (stat) \pm 0.26 (sys) in good agreement with the expectation from QCD
Pubblicazioni consigliate
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
