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 sigma(h)0 = (41.60 +/- 0.16) nb, and R(l) = 20.69 +/- 0.09. The corresponding number of light neutrino species is N(v) = 2.983 +/- 0.034. The lepton pair forward-backward' asymmetry is used to derive the ratio of vector to axial-vector couplings of leptons: g(V)2(M(Z)2)/g(A)2(M(Z)2) = 0.0058 +/- 0.0011. An application of these results to constrain one model with extra Z bosons is presented.

Z production cross sections and lepton pair forward-backward asymmetries / Buskulic, D., Casper, D., de Bonis, I., Decamp, D., Chez, P., Goy, C., Lees, J.-P., Minard, M.-N., Odier, P., Pietrzyk, B., Ariztizabal, F., Comas, P., Crespo, J.M., Efthymiopoulos, I., Fernandez, E., Fernandez-Bosman, M., Gaitan, V., Garrido, Ll., Martinez, M., Mattison, T., et al.. - In: ZEITSCHRIFT FÜR PHYSIK. C, PARTICLES AND FIELDS. - ISSN 0170-9739. - STAMPA. - 62:4(1994), pp. 539-550. [10.1007/BF01574159]

Z production cross sections and lepton pair forward-backward asymmetries

Creanza, D.;Iaselli, G.;Maggi, G.;
1994

Abstract

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 sigma(h)0 = (41.60 +/- 0.16) nb, and R(l) = 20.69 +/- 0.09. The corresponding number of light neutrino species is N(v) = 2.983 +/- 0.034. The lepton pair forward-backward' asymmetry is used to derive the ratio of vector to axial-vector couplings of leptons: g(V)2(M(Z)2)/g(A)2(M(Z)2) = 0.0058 +/- 0.0011. An application of these results to constrain one model with extra Z bosons is presented.
1994
Z production cross sections and lepton pair forward-backward asymmetries / Buskulic, D., Casper, D., de Bonis, I., Decamp, D., Chez, P., Goy, C., Lees, J.-P., Minard, M.-N., Odier, P., Pietrzyk, B., Ariztizabal, F., Comas, P., Crespo, J.M., Efthymiopoulos, I., Fernandez, E., Fernandez-Bosman, M., Gaitan, V., Garrido, Ll., Martinez, M., Mattison, T., et al.. - In: ZEITSCHRIFT FÜR PHYSIK. C, PARTICLES AND FIELDS. - ISSN 0170-9739. - STAMPA. - 62:4(1994), pp. 539-550. [10.1007/BF01574159]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11589/4138
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