A PRECISE MEASUREMENT OF THE Z RESONANCE PARAMETERS THROUGH ITS HADRONIC DECAYS

被引：56

作者：

ABREU, P

ADAM, W

ADAMI, F

ADYE, T

ALEKSEEV, GD

ALLABY, JV

ALLEN, P

ALMEHED, S

ALTED, F

ALVSVAAG, SJ

AMALDI, U

ANASSONTZIS, E

APEL, WD

ASMAN, B

FERRERES, CA

AUGUSTIN, JE

AUGUSTINUS, A

BAILLON, P

BAMBADE, P

BARAO, F

BARBIELLINI, G

BARDIN, DY

BARONCELLI, A

BARRING, O

BARTL, W

BATES, MJ

BAUBILLIER, M

BECKS, KH

BEESTON, CJ

BEILLIERE, P

BELOKOPYTOV, I

BELTRAN, P

BENEDIC, D

BENLLOCH, JM

BERGGREN, M

BERTRAND, D

BIAGI, S

BIANCHI, F

BIBBY, JH

BILENKY, MS

BILLOIR, P

BJARNE, J

BLOCH, D

BOGOLUBOV, PN

BOLLINI, D

BOLOGNESE, T

BONAPART, M

BOOTH, PSL

BORATAV, M

BORGEAUD, P

机构：

[1] CENS,DEPT PHYS HAUTE ETUD,F-91191 GIF SUR YVETTE,FRANCE

[2] DUBNA JOINT NUCL RES INST,MOSCOW 101000,USSR

[3] IST NAZL FIS NUCL,TRIESTE,ITALY

[4] UNIV LUND,DEPT PHYS,S-22361 LUND,SWEDEN

[5] UNIV STOCKHOLM,INST PHYS,S-11346 STOCKHOLM,SWEDEN

[6] UNIV KARLSRUHE,INST EXPTL KERNPHYS,W-7500 KARLSRUHE 1,GERMANY

[7] IST SUPER SANITA,IST NAZL FIZ NUCL,I-00161 ROME,ITALY

[8] UNIV PARIS 11,ACCELERATEUR LINEAIRE LAB,F-91405 ORSAY,FRANCE

[9] UNIV ROMA TOR VERGATA,DIPARTIMENTO FIS,I-00173 ROME,ITALY

[10] UNIV LIBRE BRUXELLES,B-1050 BRUSSELS,BELGIUM

[11] UNIV PARIS 06,PHYS NUCL HAUTES ETUD LAB,F-75230 PARIS 05,FRANCE

[12] UNIV PARIS 07,F-75221 PARIS 05,FRANCE

[13] UNIV GESAMTHSCH WUPPERTAL,FACHBEREICH PHYS,W-5600 WUPPERTAL 1,GERMANY

[14] GRP DELPHI,CTR RECH NUCL,DIV HAUTES ENERGIES,F-67037 STRASBOURG,FRANCE

[15] UNIV ETAT MONS,FAC SCI,SERV PHYS PARTICULES,B-7000 MONS,BELGIUM

[16] UNIV TURIN,DIPARTIMENTO FIS SPERIMENTALE,I-10125 TURIN,ITALY

[17] IST NAZL FIS NUCL,TURIN,ITALY

[18] NATL INST NUCL PHYS,MILAN,ITALY

[19] IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011

[20] UNIV BOLOGNA,DEPARTIMENTO FIS,I-40126 BOLOGNA,ITALY

[21] IST NAZL FIS NUCL,PADUA,ITALY

[22] IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011

[23] AUSTRIAN ACAD SCI,INST HOCHENERGIEPHYS,A-1050 VIENNA,AUSTRIA

[24] RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND

[25] CERN,CH-1211 GENEVA 23,SWITZERLAND

[26] UNIV VALENCIA,CSIC,CTR MIXTO,INST FIS CORPUSCULAR,E-46100 BURJASSOT,SPAIN

[27] UNIV BERGEN,DEPT PHYS,N-5007 BERGEN,NORWAY

[28] UNIV ATHENS,PHYS LAB,GR-10680 ATHENS,GREECE

[29] UNIV SANTANDER,FAC CIENCIAS,E-39005 SANTANDER,SPAIN

[30] UNIV TRIESTE,DEPARTIMENTO FIS,I-34127 TRIESTE,ITALY

[31] UNIV UDINE,IST FIS,I-33100 UDINE,ITALY

[32] UNIV OXFORD,NUCL PHYS LAB,OXFORD OX1 3RH,ENGLAND

[33] COLL FRANCE,PHYS CORPUSCULAIRE LAB,F-75231 PARIS 05,FRANCE

[34] SERPUKHOV HIGH ENERGY PHYS INST,SERPUKHOV 142284,USSR

[35] DEMOCRITOS NUCL RES CTR,GREEK ATOM ENERGY COMMISS,GR-15310 ATHENS,GREECE

[36] UNIV INSTELLING ANTWERP,DEPT PHYS,B-2610 WILRIJK,BELGIUM

[37] UNIV LIVERPOOL,DEPT PHYS,LIVERPOOL L69 3BX,ENGLAND

[38] IST NAZL FIS NUCL,BOLOGNA,ITALY

[39] UNIV UPPSALA,DEPT RADIAT SCI,S-75121 UPPSALA,SWEDEN

[40] UNIV GENOA,DIPARTIMENTO FIS,I-16146 GENOA,ITALY

[41] UNIV OSLO,DEPT PHYS,N-1000 OSLO 3,NORWAY

[42] UNIV HELSINKI,DEPT HIGH ENERGY PHYS,SF-00170 HELSINKI 17,FINLAND

[43] UNIV MILAN,DEPARTIMENTO FIS,I-20133 MILAN,ITALY

[44] UNIV PADUA,DEPARTIMENTO FIS,I-35131 PADUA,ITALY

[45] NIELS BOHR INST,DK-2100 COPENHAGEN 0,DENMARK

[46] NATL TECH UNIV ATHENS,DEPT PHYS,GR-15773 ATHENS,GREECE

[47] IST NAZL FIS NUCL,GENOA,ITALY

[48] NATL INST HIGH ENERGY PHYS,1009 DB AMSTERDAM,NETHERLANDS

[49] INST NUCL STUDIES,WARSAW,POLAND

[50] UNIV WARSAW,PL-00681 WARSAW,POLAND

来源：

PHYSICS LETTERS B | 1990年 / 241卷 / 03期

关键词：

D O I：

10.1016/0370-2693(90)91668-2

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

A measurement of the cross section for e+e- → hadrons using 11 000 hadronic decays of the Z boson at ten different center-of-mass energies is presented. A three-parameter fit gives the following values for the Z mass Mz, the total width Γz, the product of the electronic and hadronic partial widths ΓeΓh, and the unfolded pole cross section σ0: MZ=91.171±0.030(stat)±0.030 (beam) GeV, ΓZ=2.511±0.065 GeV, ΓeΓh=0.148±0.006 (stat.)±0.004 (syst.) GeV2, σ0=41.6±0.7(stat.)±1.1 (syst.) nb,. Good agreement with the predictions of the standard model is observed. From a two-parameter fit the number of massless neutrino generations is found to be Nν = 2.97±0.26. Thus the hypothesis of a fourth neutrino with mass less than 40 GeV is excluded with 95% confidence level. Combining the cross section measurements with the ratio Γℓ Γh reported in another DELPHI paper [Phys. Lett. B 241 (1990) 425], the hadronic, leptonic and invisible widths are found to be Γh=1741±61 MeV, Γℓ=85.1±2.9 MeV, Γh Γℓ=20.45±0.98, Γinv=515±54 MeV, in good agreement with the standard model. © 1990.

引用

页码：435 / 448

页数：14