An analysis based on 124000 selected tau pairs recorded by the ALEPH detector at LEP provides the vector (V) and axial-vector (A) spectral functions of hadronic tau decays together with their total widths. This allows the evaluation of finite energy chiral sum rules that are weighted integrals over the (V - A) spectral functions. In addition, a precise measurement of alpha(s) along with a determination of nonperturbative contributions at the tau mass scale is performed. The experimentally and theoretically most robust determination of alpha(s)(M-tau(2)) is obtained from the (V + A) fit that yields alpha(s)(M-tau(2)) = 0.334 +/- 0.022 giving alpha(s)(M-Z(2)) = 0.1202 +/- 0.0027 after the extrapolation to the mass of the Z boson. The approach of the Operator Product Expansion (OPE) is tested experimentally studying the evolution of the tau hadronic widths to masses smaller than the tau mass.
Measurement of the axial-vector tau spectral functions and determination of alpha(s)(M-tau(2)) from hadronic tau decays / R. Barate, D. Buskulic, D. Decamp, P. Ghez, C. Goy, J. Lees, A. Lucotte, E. Merle, M. Minard, J. Nief, B. Pietrzyk, R. Alemany, G. Boix, M. Casado, M. Chmeissani, J. Crespo, M. Delfino, E. Fernandez, M. Fernandez-Bosman, L. Garrido, E. Grauges, A. Juste, M. Martinez, G. Merino, R. Miquel, L. Mir, I. Park, A. Pascual, J. Perlas, I. Riu, F. Sanchez, A. Colaleo, D. Creanza, M. de Palma, G. Gelao, 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, U. Becker, P. Bright-Thomas, D. Casper, M. Cattaneo, V. Ciulli, G. Dissertori, H. Drevermann, R. Forty, M. Frank, R. Hagelberg, J. Hansen, J. Harvey, P. Janot, B. Jost, I. Lehraus, P. Mato, A. Minten, L. Moneta, A. Pacheco, J. Pusztaszeri, F. Ranjard, L. Rolandi, D. Rousseau, D. Schlatter, M. Schmitt, O. Schneider, W. Tejessy, F. Teubert, I. Tomalin, H. Wachsmuth, A. Wagner, Z. Ajaltouni, F. Badaud, G. Chazelle, O. Deschamps, A. Falvard, C. Ferdi, P. Gay, C. Guicheney, P. Henrard, J. Jousset, B. Michel, S. Monteil, J. Montret, D. Pallin, F. Perret, F. Podlyski, J. Proriol, P. Rosnet, J. Hansen, J. Hansen, P. Hansen, B. Nilsson, B. Rensch, A. Waananen, G. Daskalakis, A. Kyriakis, C. Markou, E. Simopoulou, I. Siotis, A. Vayaki, A. Blondel, G. Bonneaud, J. Brient, P. Bourdon, A. Rouge, M. Rumpf, A. Valassi, M. Verderi, H. Videau, E. Focardi, G. Parrini, K. Zachariadou, M. Corden, C. Georgiopoulos, D. Jaffe, A. Antonelli, G. Bencivenni, G. Bologna, F. Bossi, P. Campana, G. Capon, F. Cerutti, V. Chiarella, G. Felici, P. Laurelli, G. Mannocchi, F. Murtas, G. Murtas, L. Passalacqua, M. Pepe-Altarelli, L. Curtis, A. Halley, J. Lynch, P. Negus, V. O'Shea, C. Raine, J. Scarr, K. Smith, P. Teixeira-Dias, A. Thompson, E. Thomson, O. Buchmuller, S. Dhamotharan, C. Geweniger, G. Graefe, P. Hanke, G. Hansper, V. Hepp, E. Kluge, A. Putzer, J. Sommer, K. Tittel, S. Werner, M. Wunsch, R. Beuselinck, D. Binnie, W. Cameron, P. Dornan, M. Girone, S. Goodsir, E. Martin, N. Marinelli, A. Moutoussi, J. Nash, J. Sedgbeer, P. Spagnolo, M. Williams, V. Ghete, P. Girtler, E. Kneringer, D. Kuhn, G. Rudolph, A. Betteridge, C. Bowdery, P. Buck, P. Colrain, G. Crawford, A. Finch, F. Foster, G. Hughes, R. Jones, M. Williams, I. Giehl, A. Greene, C. Hoffmann, K. Jakobs, K. Kleinknecht, G. Quast, B. Renk, E. Rohne, H. Sander, P. van Gemmeren, C. Zeitnitz, J. Aubert, C. Benchouk, A. Bonissent, G. Bujosa, J. Carr, P. Coyle, F. Etienne, O. Leroy, F. Motsch, P. Payre, M. Talby, A. Sadouki, M. Thulasidas, K. Trabelsi, M.R.A. Aleppo, M. Antonelli, F. Ragusa, R. Berlich, W. Blum, V. Buscher, H. Dietl, G. Ganis, H. Kroha, G. Lutjens, C. Mannert, W. Manner, H. Moser, S. Schael, R. Settles, H. Seywerd, H. Stenzel, W. Wiedenmann, G. Wolf, J. Boucrot, O. Callot, S. Chen, A. Cordier, M. Davier, L. Duflot, J. Grivaz, P. Heusse, A. Hocker, A. Jacholkowska, D. Kim, F. Le Diberder, J. Lefrancois, A. Lutz, M. Schune, E. Tournefier, J. Veillet, I. Videau, D. Zerwas, P. Azzurri, G. Bagliesi, G. Batignani, S. Bettarini, T. Boccali, C. Bozzi, G. Calderini, M. Carpinelli, N. Ciocci, R. Dell'Orso, R. Fantechi, I. Ferrante, L. Foa, F. Forti, A. Giassi, M. Giorgi, A. Gregorio, F. Ligabue, A. Lusiani, P. Marrocchesi, A. Messineo, F. Palla, G. Rizzo, G. Sanguinetti, A. Sciaba, R. Tenchini, G. Tonelli, C. Vannini, A. Venturi, P. Verdini, G. Blair, L. Bryant, J. Chambers, M. Green, T. Medcalf, P. Perrodo, J. Strong, J. von Wimmersperg-Toeller, D. Botterill, R. Clifft, T. Edgecock, S. Haywood, P. Norton, J. Thompson, A. Wright, B. Bloch-Devaux, P. Colas, S. Emery, W. Kozanecki, E. Lancon, M. Lemaire, E. Locci, P. Perez, J. Rander, J. Renardy, A. Roussarie, J. Schuller, J. Schwindling, A. Trabelsi, B. Vallage, S. Black, J. Dann, R. Johnson, H. Kim, N. Konstantinidis, A. Litke, M. McNeil, G. Taylor, C. Booth, C. Brew, S. Cartwright, F. Combley, M. Kelly, M. Lehto, J. Reeve, L. Thompson, K. Affholderbach, A. Bohrer, S. Brandt, G. Cowan, C. Grupen, P. Saraiva, L. Smolik, F. Stephan, M. Apollonio, L. Bosisio, R. Della Marina, G. Giannini, B. Gobbo, G. Musolino, J. Rothberg, S. Wasserbaech, S. Armstrong, E. Charles, P. Elmer, D. Ferguson, Y. Gao, S. Gonzalez, T. Greening, O. Hayes, H. Hu, S. Jin, P. McNamara, J. Nachtman, J. Nielsen, W. Orejudos, Y. Pan, Y. Saadi, I. Scott, J. Walsh, S. Wu, X. Wu, G. Zobernig. - In: THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS. - ISSN 1434-6044. - 4:3(1998), pp. 409-431. [10.1007/s100520050217]
Measurement of the axial-vector tau spectral functions and determination of alpha(s)(M-tau(2)) from hadronic tau decays
M.R.A. Aleppo;F. Ragusa;
1998
Abstract
An analysis based on 124000 selected tau pairs recorded by the ALEPH detector at LEP provides the vector (V) and axial-vector (A) spectral functions of hadronic tau decays together with their total widths. This allows the evaluation of finite energy chiral sum rules that are weighted integrals over the (V - A) spectral functions. In addition, a precise measurement of alpha(s) along with a determination of nonperturbative contributions at the tau mass scale is performed. The experimentally and theoretically most robust determination of alpha(s)(M-tau(2)) is obtained from the (V + A) fit that yields alpha(s)(M-tau(2)) = 0.334 +/- 0.022 giving alpha(s)(M-Z(2)) = 0.1202 +/- 0.0027 after the extrapolation to the mass of the Z boson. The approach of the Operator Product Expansion (OPE) is tested experimentally studying the evolution of the tau hadronic widths to masses smaller than the tau mass.
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