Z production cross sections and lepton pair forward-backward asymmetries

D. Buskulic, D. Casper, I. De Bonis, D. Decamp, P. Chez, C. Goy, J. P. Lees, M. N. Minard, P. Odier, B. Pietrzyk, F. Ariztizabal, P. Comas, J. M. Crespo, I. Efthymiopoulos, E. Fernandez, M. Fernandez-Bosman, V. Gaitan, Ll Garrido, M. Martinez, T. MattisonS. Orten, A. Pacheco, C. Padilla, A. Pascual, D. Creanza, M. de Palma, A. Farilla, G. Iaselli, G. Maggi, N. Marinelli, S. Natali, S. Nuzzo, A. Ranieri, G. Raso, F. Romano, F. Ruggieri, G. Selvaggi, L. Silvestris, P. Tempesta, G. Zito, Y. Chai, D. Huang, X. Huang, J. Lin, T. Wang, Y. Xie, D. Xu, R. Xu, J. Zhang, L. Zhang, W. Zhao, E. Blucher, G. Bonvicini, J. Boudreau, H. Drevermann, R. W. Forty, G. Ganis, C. Gay, M. Girone, R. Hagelberg, J. Harvey, J. Hilgart, R. Jacobsen, B. Jost, J. Knobloch, I. Lehraus, M. Maggi, C. Markou, P. Mato, H. Meinhard, A. Minten, R. Miquel, K. Moffeit, P. Palazzi, J. R. Pater, J. A. Perlas, P. Perrodo, J. F. Pusztaszeri, F. Ranjard, L. Rolandi, J. Rothberg, T. Ruan, M. Saich, D. Schlatter, M. Schmelling, F. Sefkow, W. Tejessy, I. R. Tomalin, R. Veenhof, H. Wachsmuth, S. Wasserbaech, W. Wiedenmann, T. Wildish, W. Witzeling, J. Wotschack, Z. Ajaltouni, M. Bardadin-Otwinowska, A. Barres, C. Boyer, A. Falvard

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46 Citations (Scopus)


Precise values of the Z resonance cross sections and lepton pair forward-backward asymmetries are measured from a sample of 1.3 million Z decays into hadrons and charged leptons taken with the ALEPH detector at LEP. A silicon-tungsten luminosity calorimeter was installed in ALEPH in 1992, permitting the determination of the absolute luminosity to a systematic precision of 0.15% (experimental) and 0.25% (theoretical). This is combined with a better understanding of the hadronic event selection and an improved tau pair selection. Including the ALEPH results of the past three years one obtains σh0 =(41.60±0.16) nb, and Rl=20.69±0.09. The corresponding number of light neutrino species is Nv =2.983±0.034. The lepton pair forward-backward asymmetry is used to derive the ratio of vector to axial-vector couplings of leptons:gV2(MZ2)/gA 2(MZ2)=0.0058 ±0.0011. An application of these results to constrain one model with extra Z bosons is presented. © 1994 Springer-Verlag.
Original languageEnglish
Pages (from-to)539-550
JournalZeitschrift fur Physik C-Particles and Fields
Issue number4
Publication statusPublished - 1 Jan 1994


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