151. DETERMINATION OF Z0 RESONANCE PARAMETERS AND COUPLINGS FROM ITS HADRONIC AND LEPTONIC DECAYS
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ABREU, P ADAM, W ADAMI, F ADYE, T AKESSON, T and ALEKSEEV, GD ALLEN, P ALMEHED, S ALTED, F ALVSVAAG, SJ and AMALDI, U ANASSONTZIS, E ANTILOGUS, P APEL, WD and APSIMON, RJ ASMAN, B ASTIER, P AUGUSTIN, JE AUGUSTINUS, A BAILLON, P BAMBADE, P BARAO, F BARBIELLINI, G and BARDIN, DY BARONCELLI, A BARRING, O BARTL, W BATTAGLIA, M BATES, MJ BAUBILLIER, M BECKS, KH BEESTON, CJ and BEGALLI, M BEILLIERE, P BELOKOPYTOV, Y BELTRAN, P and BENEDIC, D BENLLOCH, JM BERGGREN, M BERTRAND, D BIAGI, S and BIANCHI, F BIBBY, JH BILENKY, MS BILLOIR, P BJARNE, J BLOCH, D BLYTH, S BOGOLUBOV, PN BOLOGNESE, T and BONAPART, M BONESINI, M BONIVENTO, W BOOTH, PSL BORATAV, M BORGEAUD, P BORISOV, G BORNER, H BOSIO, C BOTNER, O BOUQUET, B BOZZO, M BRAIBANT, S BRANCHINI, P and BRAND, KD BRENNER, RA BRICMAN, C BROWN, RCA BRUMMER, N and BRUNET, JM BUGGE, L BURAN, T BURMEISTER, H BUYTAERT, JAMA CACCIA, M CALVI, M ROZAS, AJC CAMPAGNE, JE and CAMPION, A CAMPORESI, T CANALE, V CAO, F CARROLL, L and CASO, C CASTELLI, E GIMENEZ, MVC CATTAI, A CAVALLO, FR and CERRITO, L CHAPKIN, M CHARPENTIER, P CHECCHIA, P and CHELKOV, GA CHEVALIER, L CHLIAPNIKOV, P CHOROWICZ, V and CIRIO, R CLARA, MP COLLINS, P CONTRERAS, JL CONTRI, R and COSME, G COUCHOT, F CRAWLEY, HB CRENNELL, D and CROSETTI, G CROSLAND, N CROZON, M MAESTRO, JC CZELLAR, S and DAGORET, S DAHLJENSEN, E DALMAGNE, B DAM, M and DAMGAARD, G DARBO, G DAUBIE, E DAUNCEY, PD DAVENPORT, M and DAVID, P DEANGELIS, A DEBEER, M DEBOECK, H DEBOER, W and DECLERCQ, C LASO, MDMD DEGROOT, N DELAVAISSIERE, C and DELOTTO, B DEMIN, A DEFOIX, C DELIKARIS, D DELORME, S and DELPIERRE, P DEMARIA, N DERKAOUI, J DICIACCIO, L and DIJKSTRA, H DJAMA, F DOLBEAU, J DONSZELMANN, M DOROBA, K and DRACOS, M DREES, J DRIS, M DUFOUR, Y DULINSKI, W and DZHELYADIN, R EEK, LO EEROLA, PAM EKELOF, T EKSPONG, G and PEISERT, AE ENGEL, JP FASSOULIOTIS, D ALONSO, MF and FERRER, A FILIPPAS, TA FIRESTONE, A FOETH, H FOKITIS, E and FOLEGATI, P FONTANELLI, F FORSBACH, H FRANEK, B and FRENKIEL, P FRIES, DC FRODESEN, AG FRUHWIRTH, R and FULDAQUENZER, F FURNIVAL, K FURSTENAU, H FUSTER, J GAGO, JM GALEAZZI, G GAMBA, D GARCIA, C GARCIA, J and GASPARINI, U GAVILLET, P GAZIS, EN GERBER, JP and GIACOMELLI, P GLITZA, KW GOKIELI, R GOLOVATYUK, VM and CADENAS, JJGY GOOBAR, A GOPAL, G GORSKI, M GRACCO, V and GRANT, A GRARD, F GRAZIANI, E GROS, MH GROSDIDIER, G and GROSSETETE, B GUMENYUK, S GUY, J HAHN, F HAHN, M and HAIDER, S HAJDUK, Z HAKANSSON, A HALLGREN, A HAMACHER, K and DEMONCHENAULT, GH HARRIS, FJ HECK, BW HERBST, I and HERNANDEZ, JJ HERQUET, P HERR, H HIETANEN, I HIGON, E and HILKE, HJ HODGSON, SD HOFMOKL, T HOLMES, R HOLMGREN, SO HOLTHUIZEN, D HONORE, PF HOOPER, JE HOULDEN, M and HRUBEC, J HULTH, PO HULTQVIST, K HUSSON, D HYAMS, BD and IOANNOU, P ISENHOWER, D IVERSEN, PS JACKSON, JN JALOCHA, P JARLSKOG, G JARRY, P JEANMARIE, B JOHANSSON, EK and JOHNSON, D JONKER, M JONSSON, L JUILLOT, P KALKANIS, G and KALMUS, G KANTARDJIAN, G KAPUSTA, F KATSANEVAS, S and KATSOUFIS, EC KERANEN, R KESTEMAN, J KHOMENKO, BA and KHOVANSKI, NN KING, B KJAER, NJ KLEIN, H KLEMPT, W and KLOVNING, A KLUIT, P KOEHNE, JH KOENE, B KOKKINIAS, P and KOPF, M KORATZINOS, M KORCYL, K KORYTOV, AV KORZEN, B KOSTUKHIN, V KOURKOUMELIS, C KREUZBERGER, T and KROLIKOWSKI, J KRUENERMARQUIS, U KRUPINSKI, W KUCEWICZ, W and KULKA, K KURVINEN, K LACASTA, C LAMBROPOULOS, C and LAMSA, JW LANCERI, L LAPIN, V LAUGIER, JP LAUHAKANGAS, R and LEDER, G LEDROIT, F LEMONNE, J LENZEN, G LEPELTIER, V LETESSIERSELVON, A LIKO, D LIEB, E LILLETHUN, E and LINDGREN, J LIPNIACKA, A LIPPI, I LLOSA, R LOERSTAD, B and LOKAJICEK, M LOKEN, JG AGUERA, MAL LOPEZFERNANDEZ, A and LOS, M LOUKAS, D LOUNIS, A LOZANO, JJ LUCOCK, R and LUTZ, P LYONS, L MAEHLUM, G MAILLARD, J MALTEZOS, A and MALTEZOS, S MANDL, F MARCO, J MARGONI, M MARIN, JC and MARKOU, A MARTI, S MATHIS, L MATORRAS, F MATTEUZZI, C and MATTHIAE, G MAZZUCATO, M MCCUBBIN, M MCKAY, R and MCNULTY, R MENICHETTI, E MEOLA, G MERONI, C MEYER, WT and MICHELOTTO, M MITAROFF, WA MITSELMAKHER, GV MJOERNMARK, U MOA, T MOELLER, R MOENIG, K MONGE, MR MORETTINI, P and MUELLER, H MULLER, H MURRAY, WJ MUYATT, G NARAGHI, F and NAUKORZEN, U NAVARRIA, FL NEGRI, P NIELSEN, BS and NIJJHAR, B NIKOLAENKO, V OBRAZTSOV, V OLSHEVSKI, AG and ORAVA, R OSTANKOV, A OURAOU, A PAIN, R PALKA, H and PAPADOPOULOU, T PAPE, L PASSERI, A PEGORARO, M and PEREVOZCHIKOV, V PERNICKA, M PERROTTA, A PIERRE, F and PIMENTA, M PINGOT, O PINSENT, A POL, ME POLOK, G and POROPAT, P PRIVITERA, P PULLIA, A PYYHTIA, J RADOJICIC, D RAGAZZI, S RANGE, WH RATOFF, PN READ, AL REDAELLI, NG REGLER, M REID, D RENTON, PB RESVANIS, LK and RICHARD, F RICHARDSON, M RIDKY, J RINAUDO, G RODITI, I and ROMERO, A RONCAGLIOLO, I RONCHESE, P RONNQVIST, C and ROSENBERG, EI ROSSI, U ROSSO, E ROUDEAU, P ROVELLI, T and RUCKSTUHL, W RUHLMANN, V RUIZ, A RYBICKI, K and SAARIKKO, H SACQUIN, Y SALT, J SANCHEZ, E SANCHEZ, J and SANNINO, M SCHAEFFER, M SCHAEL, S SCHNEIDER, H SCURI, F and SEGAR, AM SEKULIN, R SESSA, M SETTE, G SEUFERT, R and SHELLARD, RC SIEGRIST, P SIMONETTI, S SIMONETTO, F and SISSAKIAN, AN SKAALI, TB SKJEVLING, G SMADJA, G SMITH, GR SMIRNOV, N SOSNOWSKI, R SPASSOFF, TS SPIRITI, E and SQUARCIA, S STAECK, H STANESCU, C STAVROPOULOS, G and STICHELBAUT, F STOCCHI, A STRAUSS, J STRUB, R and STUBENRAUCH, CJ SZCZEKOWSKI, M SZEPTYCKA, M SZYMANSKI, P and TABARELLI, T TAVERNIER, S TCHIKILEV, O THEODOSIOU, GE and TILQUIN, A TIMMERMANS, J TIMOFEEV, VG TKATCHEV, LG and TODOROV, T TOET, DZ TORTORA, L TRAINOR, MT TREILLE, D and TREVISAN, U TRISCHUK, W TRISTRAM, G TRONCON, C and TSIROU, A TSYGANOV, EN TURALA, M TURCHETTA, R TURLUER, ML TUUVA, T TYAPKIN, IA TYNDEL, M TZAMARIAS, S and UEBERSCHAER, B UEBERSCHAER, S ULLALAND, O UVAROV, VA and VALENTI, G VALLAZZA, E FERRER, JAV VANAPELDOORN, GW and VANDAM, P VANDONINCK, WK VANEIJNDHOVEN, N VANDERVELDE, C and VARELA, J VAZ, P VEGNI, G VELASCO, J VENTURA, L and VENUS, W VERBEURE, F VERTOGRADOV, LS VIBERT, L VILANOVA, D VLASOV, EV VODOPYANOV, AS VOLLMER, M VOLPONI, S and VOULGARIS, G VOUTILAINEN, M VRBA, V WAHLEN, H WALCK, C and WALDNER, F WAYNE, M WEILHAMMER, P WERNER, J and WETHERELL, AM WICKENS, JH WIKNE, J WILKINSON, GR and WILLIAMS, WSC WINTER, M WORMALD, D WORMSER, G WOSCHNAGG, K YAMDAGNI, N YEPES, P ZAITSEV, A ZALEWSKA, A and ZALEWSKI, P ZEVGOLATAKOS, E ZHANG, G ZIMIN, NI ZITO, M and ZITOUN, R FUNCHAL, RZ ZUMERLE, G ZUNIGA, J
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High Energy Physics::Experiment - Abstract
From measurements of the cross sections for e+ e - –> hadrons and the cross sections and forward-backward charge-asymmetries for e+ e- –> e+ e-, mu+ mu- and tau+ tau- at several centre-of-mass energies around the Z0 pole with the DELPHI apparatus, using approximately 150000 hadronic and leptonic events from 1989 and 1990, one determines the following Z0 parameters: the mass and total width M(Z) = 91.177 +/- 0.022 GeV, GAMMA(Z) = 2.465 +/- 0.020 GeV, the hadronic and leptonic partial widths GAMMA(h) = 1.726 +/- 0.019 GeV, GAMMA(t) = 83.4 +/- 0.8 MeV, the invisible width GAMMA(inv) = 488 +/- 17 MeV, the ratio of hadronic over leptonic partial widths R(Z)z = 20.70 +/- 0.29 and the Born level hadronic peak cross section sigma-0 = 41.84 +/- 0.45 nb. A flavour-independent measurement of the leptonic cross section gives very consistent results to those presented above (GAMMA(t) = 83.7 +/- 0.8 MeV). From these results the number of light neutrino species is determined to be N(nu) = 2.94 +/0. 10. The individual leptonic widths obtained are: GAMMA(e) = 82.4 +/- 1.2 MeV, GAMMA(mu) = 86.9 +/- 2.1 MeV and GAMMA(tau) = 82.7 +/- 2.4 MeV. Assuming universality, the squared vector and axial-vector couplings of the Z0 to charged leptons are: VBAR(t)2 = 0.0003 +/- 0.0010 and ABAR(l)2 = 0.2508 +/- 0.0027. These values correspond to the electroweak parameters: rho(eff) = 1.003 +/- 0.011 and sin2-theta(W)eff = 0.241 +/- 0.009. Within the Minimal Standard Model (MSM), the results can be expressed in terms of a single parameter: sin2-theta(W)MSBAR = 0.2338 +/- 0.0027. All these values are in good agreement with the predictions of the MSM. Fits yield 43 < m(top) < 215 GeV at the 95% level. Finally, the measured values of GAMMA(Z) and GAMMA(inv), are used to derive lower mass bounds for possible new particles.
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- 1991