Measurements of cross sections and forward-backward asymmetries at the Z resonance and determination of electroweak parameters

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	Measurements of cross sections and forward-backward asymmetries at the Z resonance and determination of electroweak parameters
刊名	EUROPEAN PHYSICAL JOURNAL C
	2000
卷号	16 期号:1 页码:1-40
关键词	TOP-QUARK MASS ANGLE BHABHA SCATTERING LEPTON-PAIR PRODUCTION CARLO EVENT GENERATOR BOSON DECAY-RATE ART. NO. 052001 MONTE-CARLO RADIATIVE-CORRECTIONS COLLIDER DETECTOR QED CORRECTIONS
通讯作者	Acciarri, M (reprint author), Ist Nazl Fis Nucl, Sez Milano, Via Celoria 16, I-20133 Milan, Italy.
英文摘要	We report on measurements of hadronic and leptonic cross sections and leptonic forward backward asymmetries performed with the L3 detector in the years 1993-95. A total luminosity of 103 pb(-1) nas collected at centre-of-mass energies root s approximate to m(Z) and root s approximate to m(Z) +/- 1.8 GeV which corresponds to 2.5 million hadronic and 245 thousand leptonic events selected. These data lead to a significantly improved determination of Z parameters. From the total cross sections, combined with our measurements in 1990-92, we obtain the final results: m(Z) = 91 189.8 +/- 3.1 MeV, Gamma(Z) = 2502.4 +/- 4.2 MeV, Gamma(had) = 1751.1 +/- 3.8 MeV, Gamma(l) = 84.14 +/- 0.17 MeV. An invisible width of Gamma(inv) = 499.1 +/- 2.9 MeV is derived which in the Standard Model yields for the number of light neutrino species N-nu = 2.978 +/- 0.014. Adding our results on the leptonic forward-backward asymmetries and the tau polarisation, the effective vector and axial-vector coupling constants of the neutral weak current to charged leptons are determined to be (g) over bar(V)(l) = -0.0397+/-0.0017 and (g) over bar A(l) = -0.50153+/-0.00053. Including our measurements of the Z --> b (b) over bar forward-backward and quark charge asymmetries a value for the effective electroweak mixing angle of sin(2)<(theta)over bar>(W) = 0.23093 +/- 0.00066 is derived. All these measurements are in good agreement with the Standard Model of electroweak interactions. Using all our measurements of electroweak observables an upper limit on the mass of the Standard Model Higgs boson of m(H) < 133 GeV is set at 95% confidence level.
学科主题	Physics
类目[WOS]	Physics, Particles & Fields
收录类别	SCI
语种	英语
WOS记录号	WOS:000088856000001
公开日期	2016-02-25
内容类型	期刊论文
源URL	[http://ir.ihep.ac.cn/handle/311005/212062]
专题	高能物理研究所_粒子天体物理中心
推荐引用方式 GB/T 7714	. Measurements of cross sections and forward-backward asymmetries at the Z resonance and determination of electroweak parameters[J]. EUROPEAN PHYSICAL JOURNAL C,2000,16(1):1-40.
APA	(2000).Measurements of cross sections and forward-backward asymmetries at the Z resonance and determination of electroweak parameters.EUROPEAN PHYSICAL JOURNAL C,16(1),1-40.
MLA	"Measurements of cross sections and forward-backward asymmetries at the Z resonance and determination of electroweak parameters".EUROPEAN PHYSICAL JOURNAL C 16.1(2000):1-40.