Precision Neutral Current Asymmetry Parameter Measurements from the Tau Polarization at LEP

Measurements of the tau lepton polarization and forward-backward polarization asymmetry near the Z resonance using the OPAL detector are described. The measurements are based on analyses of tau -> e nu_e nu_tau, tau -> mu nu_mu nu_tau, tau -> pi nu_tau, tau -> rho nu_tau and tau -> a1...

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Detalles Bibliográficos
Autores principales: Abbiendi, G., Ainsley, C., Akesson, P.F., Alexander, G., Allison, John, Anagnostou, G., Anderson, K.J., Arcelli, S., Asai, S., Axen, D., Azuelos, G., Bailey, I., Ball, A.H., Barberio, E., Barlow, Roger J., Batley, R.J., Behnke, T., Bell, Kenneth Watson, Bella, G., Bellerive, A., Benelli, G., Bethke, S., Biebel, O., Bloodworth, I.J., Boeriu, O., Bock, P., Bohme, J., Bonacorsi, D., Boutemeur, M., Braibant, S., Brigliadori, L., Brown, Robert M., Burckhart, H.J., Cammin, J., Capiluppi, P., Carnegie, R.K., Caron, B., Carter, A.A., Carter, J.R., Chang, C.Y., Charlton, David G., Clarke, P.E.L., Clay, E., Cohen, I., Couchman, J., Csilling, A., Cuffiani, M., Dado, S., Dallavalle, G.Marco, Dallison, S., De Roeck, A., De Wolf, E.A., Dervan, P., Desch, K., Dienes, B., Dixit, M.S., Donkers, M., Dubbert, J., Duchovni, E., Duckeck, G., Duerdoth, I.P., Estabrooks, P.G., Etzion, E., Fabbri, F., Fanti, M., Feld, L., Ferrari, P., Fiedler, F., Fleck, I., Ford, M., Frey, A., Furtjes, A., Futyan, D.I., Gagnon, P., Gary, J.W., Gaycken, G., Geich-Gimbel, C., Giacomelli, G., Giacomelli, P., Glenzinski, D., Goldberg, J., Grandi, C., Graham, K., Gross, E., Grunhaus, J., Gruwe, M., Gunther, P.O., Gupta, A., Hajdu, C., Hanson, G.G., Harder, K., Harel, A., Harin-Dirac, M., Hauschild, M., Hawkes, C.M., Hawkings, R., Hemingway, R.J., Hensel, C., Herten, G., Heuer, R.D., Hill, J.C., Hoffman, Kara Dion, Homer, R.J., Honma, A.K., Horvath, D., Hossain, K.R., Howard, R., Huntemeyer, P., Igo-Kemenes, P., Ishii, K., Jawahery, A., Jeremie, H., Jones, C.R., Jovanovic, P., Junk, T.R., Kanaya, N., Kanzaki, J., Karapetian, G., Karlen, D., Kartvelishvili, V., Kawagoe, K., Kawamoto, T., Keeler, R.K., Kellogg, R.G., Kennedy, B.W., Kim, D.H., Klein, K., Klier, A., Kluth, S., Kobayashi, T., Kobel, M., Kokott, T.P., Komamiya, S., Kowalewski, Robert V., Kamer, T., Kress, T., Krieger, P., von Krogh, J., Krop, D., Kuhl, T., Kupper, M., Kyberd, P., Lafferty, G.D., Landsman, H., Lanske, D., Lawson, I., Layter, J.G., Leins, A., Lellouch, D., Letts, J., Levinson, L., Liebisch, R., Lillich, J., Littlewood, C., Lloyd, A.W., Lloyd, S.L., Loebinger, F.K., Long, G.D., Losty, M.J., Lu, J., Ludwig, J., Macchiolo, A., Macpherson, A., Mader, W., Marcellini, S., Marchant, T.E., Martin, A.J., Martin, J.P., Martinez, G., Mashimo, T., Mattig, Peter, McDonald, W.John, McKenna, J., McMahon, T.J., McPherson, R.A., Meijers, F., Mendez-Lorenzo, P., Menges, W., Merritt, F.S., Mes, H., Michelini, A., Mihara, S., Mikenberg, G., Miller, D.J., Mohr, W., Montanari, A., Mori, T., Nagai, K., Nakamura, I., Neal, H.A., Nisius, R., O'Neale, S.W., Oakham, F.G., Odorici, F., Oh, A., Okpara, A., Oreglia, M.J., Orito, S., Pahl, C., Pasztor, G., Pater, J.R., Patrick, G.N., Pilcher, J.E., Pinfold, J., Plane, David E., Poli, B., Polok, J., Pooth, O., Quadt, A., Rabbertz, K., Rembser, C., Renkel, P., Rick, H., Rodning, N., Roney, J.M., Rosati, S., Roscoe, K., Rossi, A.M., Rozen, Y., Runge, K., Runolfsson, O., Rust, D.R., Sachs, K., Saeki, T., Sahr, O., Sarkisian, E.K.G., Sbarra, C., Schaile, A.D., Schaile, O., Scharff-Hansen, P., Schroder, Matthias, Schumacher, M., Schwick, C., Scott, W.G., Seuster, R., Shears, T.G., Shen, B.C., Shepherd-Themistocleous, C.H., Sherwood, P., Siroli, G.P., Skuja, A., Smith, A.M., Snow, G.A., Sobie, R., Soldner-Rembold, S., Spagnolo, S., Spano, F., Sproston, M., Stahl, A., Stephens, K., Strom, David M., Strohmer, R., Stumpf, L., Surrow, B., Talbot, S.D., Tarem, S., Tasevsky, M., Taylor, R.J., Teuscher, R., Thomas, J., Thomson, M.A., Torrence, E., Towers, S., Toya, D., Trefzger, T., Trigger, I., Trocsanyi, Z., Tsur, E., Turner-Watson, M.F., Ueda, I., Vachon, B., Vollmer, C.F., Vannerem, P., Verzocchi, M., Voss, H., Vossebeld, J., Waller, D., Ward, C.P., Ward, D.R., Watkins, P.M., Watson, A.T., Watson, N.K., Wells, P.S., Wengler, T., Wermes, N., Wetterling, D., White, J.S., Wilson, G.W., Wilson, J.A., Wyatt, T.R., Yamashita, S., Zacek, V., Zer-Zion, D.
Lenguaje:eng
Publicado: 2001
Materias:
Particle Physics - Experiment
Acceso en línea:https://dx.doi.org/10.1007/s100520100714
http://cds.cern.ch/record/492929
Descripción
Sumario:Measurements of the tau lepton polarization and forward-backward polarization asymmetry near the Z resonance using the OPAL detector are described. The measurements are based on analyses of tau -> e nu_e nu_tau, tau -> mu nu_mu nu_tau, tau -> pi nu_tau, tau -> rho nu_tau and tau -> a1 nu_tau decays from a sample of 144810 e+e- -> tau+ tau- candidates corresponding to an integrated luminosity of 151 pb-1. Assuming that the tau lepton decays according to V-A theory, we measure the average tau polarization near Ecm = MZ to be <Ptau> = (-14.10 +/- 0.73 +/- 0.55)% and the tau polarization forward-backward asymmetry to be Afb = (-10.55 +/- 0.76 +/- 0.25)%, where the first error is statistical and the second systematic. Taking into account the small effects of the photon propagator, photon-Z interference and photonic radiative corrections, these results can be expressed in terms of the lepton neutral current asymmetry parameters: Atau = 0.1456 +/- 0.0076 +/- 0.0057, Ae = 0.1454 +/- 0.0108 +/- 0.0036. These measurements are consistent with the hypothesis of lepton universality and combine to give Al = 0.1455 +/- 0.0073. Within the context of the Standard Model this combined result corresponds to sin^2(theta)(lept,effective) = 0.23172 +/- 0.00092. Combing these results with those from the other OPAL neutral current measurements yields a value of sin^2(theta)(lept,effective) = 0.23211 +/- 0.00068.

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