Measurement of the Michel parameters in leptonic tau decays

Authors
Ackerstaff, K Alexander, G Allison, J Altekamp, N Anderson, KJ Anderson, S Arcelli, S Asai, S Ashby, SF Axen, D Azuelos, G Ball, AH Barberio, E Barlow, RJ Bartoldus, R Batley, JR Baumann, S Bechtluft, J Behnke, T Bell, KW Bella, G Bentvelsen, S Bethke, S Betts, S Biebel, O Biguzzi, A Bird, SD Blobel, V Bloodworth, IJ Bobinski, M Bock, P Bohme, J Boutemeur, M Braibant, S Bright-Thomas, P Brown, RM Burckhart, HJ Burgard, C Burgin, R Capiluppi, P Carnegie, RK Carter, AA Carter, JR Chang, CY Charlton, DG Chrisman, D Ciocca, C Clarke, PEL Clay, E Cohen, I Conboy, JE Cooke, OC Couyoumtzelis, C Coxe, RL Cuffani, M Dado, S Dallavalle, GM Davis, R De Jong, S del Pozo, LA de Roeck, A Desch, K Dienes, B Dixit, MS Doucet, M Dubbert, J Duchovni, E Duckeck, G Duerdoth, IP Eatough, D Estabrooks, PG Etzion, E Evans, HG Fabbri, F Fanfani, A Fanti, M Faust, AA Fiedler, F Fierro, M Fischer, HM Fleck, I Folman, R Furtjes, A Futyan, DI Gagnon, P Gary, JW Gascon, J Gascon-Shotkin, SM Geich-Gimbel, C Geralis, T Giacomelli, G Giacomelli, P Gibson, V Gibson, WR Gingrich, DM Glenzinski, D Goldberg, J Gorn, W Grandi, C Gross, E Grunhaus, J Gruwe, M Hanson, GG Hansroul, M Hapke, M Hargrove, CK Hartmann, C Hauschild, M Hawkes, CM Hawkings, R Hemingway, RJ Herndon, M Herten, G Heuer, RD Hildreth, MD Hill, JC Hillier, SJ Hobson, PR Hocker, A Homer, RJ Honma, AK Horvath, D Hossain, KR Howard, R Huntemeyer, P Igo-Kemenes, P Imrie, DC Ishii, K Jacob, FR Jawahery, A Jeremie, H Jimack, M Joly, A Jones, CR Jovanovic, P Junk, TR Karlen, D Kartvelishvili, V Kawagoe, K Kawamoto, T Kayal, PI Keeler, RK Kellogg, RG Kennedy, BW Klier, A Kluth, S Kobayashi, T Kobel, M Koetke, DS Kokott, TP Kolrep, M Komamiya, S Kowalewski, RV Kress, T Krieger, P von Krogh, J Kyberd, P Lafferty, GD Lanske, D Lauber, J Lautenschlager, SR Lawson, I Layter, JG Lazic, D Lee, AM Lefebvre, E Lellouch, D Letts, J Levinson, L Liebisch, R List, B Littlewood, C Lloyd, AW Lloyd, SL Loebinger, FK Long, GD Losty, MJ Ludwig, J Liu, D Macchiolo, A Macpherson, A Mannelli, M Marcellini, S Markopoulos, C Martin, AJ Martin, JP Martinez, G Mashimo, T Mattig, P McDonald, WJ McKenna, J Mckigney, EA McMahon, TJ McPherson, RA Meijers, F Menke, S Merritt, FS Mes, H Meyer, J Michelini, A Mihara, S Mikenberg, G Miller, DJ Mir, R Mohr, W Montanari, A Mori, T Nagai, K Nakamura, I Neal, HA Nellen, B Nisius, R O'Neale, SW Oakham, FG Odorici, F Ogren, HO Oreglia, MJ Orito, S Palinkas, J Pasztor, G Pater, JR Patrick, GN Patt, J Perez-Ochoa, R Petzold, S Pfeifenschneider, P Pilcher, JE Pinfold, J Plane, DE Poffenberger, P Poli, B Polok, J Przybycien, M Rembser, C Rick, H Robertson, S Robins, SA Rodning, N Roney, JM Roscoe, K Rossi, AM Rozen, Y Runge, K Runolfsson, O Rust, DR Sachs, K Saeki, T Sahr, O Sang, WM Sarkisyan, EKG Sbarra, C Schaile, AD Schaile, O Scharf, F Scharff-Hansen, P Schieck, J Schmitt, B Schmitt, S Schoning, A Schorner, T Schroder, M Schumacher, M Schwick, C Scott, WG Seuster, R Shears, TG Shen, BC Shepherd-Themistocleous, CH Sherwood, P Siroli, GP Sittler, A Skuja, A Smith, AM Snow, GA Sobie, R Soldner-Rembold, S Sproston, M Stahl, A Stephens, K Steuerer, J Stoll, K Strom, D Strohmer, R Tafirout, R Talbot, SD Tanaka, S Taras, P Tarem, S Teuscher, R Thiergen, M Thomson, MA von Torne, E Torrence, E Towers, S Trigger, I Trocsanyi, Z Tsur, E Turcot, AS Turner-Watson, MF Van Kooten, R Vannerem, P Verzocchi, M Vikas, P Voss, H Wackerle, F Wagner, A Ward, CP Ward, DR Watkins, PM Watson, AT Watson, NK Wells, PS Wermes, N White, JS Wilson, GW Wilson, JA Wyatt, TR Yamashita, S Yekutieli, G Zacek, V Zer-Zion, D
Citation
K. Ackerstaff et al., Measurement of the Michel parameters in leptonic tau decays, EUR PHY J C, 8(1), 1999, pp. 3-21
Citations number
52
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics
Journal title
EUROPEAN PHYSICAL JOURNAL C
ISSN journal
1434-6044 → ACNP
Volume
8
Issue
1
Year of publication
1999
Pages
3 - 21
Database
ISI
SICI code
1434-6044(199904)8:1<3:MOTMPI>2.0.ZU;2-Q
Abstract
The Michel parameters of the leptonic tau decays are measured using the OPA L detector at LEP. The parameters pe, Ee, (E delta)e (with l = e, mu) and e ta(mu), are extracted from the energy spectra of the charged decay leptons and from their energy-energy correlations. A new method involving a global likelihood fit of Monte Carlo generated events with complete detector simul ation and background treatment has been applied to the data recorded at cen ter-of-mass energies close to root s = m(Z)o corresponding to an integrated luminosity of 155 pb(-1). If e-mu universality is assumed and inferring th e tau polarization from neutral current data, the measured Michel parameter s are: rho = 0.781 +/- 0.028 +/- 0.018, xi = 0.98 +/- 0.22 +/- 0.10, eta = 0.027 +/- 0.055 +/- 0.005, xi delta = 0.65 +/- 0.14 +/- 0.07. where the value of eta has been constrained using the published OPAL measur ements of the leptonic branching ratios and the tau lifetime; Limits on non -standard coupling constants and on the masses of new gauge bosons are obta ined. The results are in agreement with the V-A prediction of the Standard Model.