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1.
Kaoru Hagiwara Dieter Haidt Seiji Matsumoto 《The European Physical Journal C - Particles and Fields》1998,2(1):95-122
We update our previous work on an analysis of the electroweak data by including new and partly preliminary data available
up to the 1996 summer conferences. The new results on the partial decay widths into and hadrons now offer a consistent interpretation of all data in the minimal standard model. The value extracted for the strong
interaction coupling constant agrees well with determinations in other areas. New constraints on the universal parameters , and are obtained from the updated measurements. No signal of new physics is found in the , , analysis once the SM contributions with GeV and those of not a too heavy Higgs boson are accounted for. The naive QCD-like technicolor model is now ruled out at the
99% CL even for the minimal model with . In the absence of a significant new physics effect in the electroweak observables, constraints on masses of the top quark,
, and Higgs boson, , are derived as a function of and the QED effective coupling . The preferred range of depends rather strongly on the actual value of : for , while for at 95% CL. Prospects due to forthcoming improved measurements of asymmetries, the mass of the weak boson
, and are discussed. Anticipating uncertainties of 0.00020 for , 20 MeV for , and 2 GeV for , the new physics contributions to the , , parameters will be constrained more severely, and, within the SM, the logarithm of the Higgs mass can be constrained to about
. The better constraints on , , and on within the minimal SM should be accompanied with matching precision in .
Received: 18 June 1997 相似文献
2.
T. Eichten H. Deden F.J. Hasert W. Krenz J. Von Krogh D. Lanske J. Morfin H. Weerts G. Bertrand-Coremans J. Sacton W. Van Doninck P. Vilain D.C. Cundy D. Haidt M. Jaffre G. Kalbfleisch S. Natali P. Musset J.L. Pinfold 《Physics letters. [Part B]》1973,46(2):281-284
The total cross-sections for -nucleon scattering have been measured. A test has been made of the muon number conservation law. A limit of 2.4 GeV is found the mass of the “Georgi-Glashow type” heavy lepton 相似文献
3.
Schukraft J. Maeshima K. Wenzel H. Haidt D. Foa L. Ali A. 《The European Physical Journal C - Particles and Fields》2004,33(1):s1-s4
The European Physical Journal C - The fourth LHC Symposium was held at Fermilab in May 2003 following the first two meetings in Russia and the third symposium in Italy. The theme of this meeting... 相似文献
4.
W. Bartel D. Cords P. Dittman R. Eichler R. Felst D. Haidt S. Kawabata H. Krehbiel B. Naroska L.H. ONeill P. Steffen W.L. Yen E. Elsen M. Helm A. Petersen P. Warming G. Weber H. Drumm C. Yanagisawa 《Physics letters. [Part B]》1981,99(3):281-286
The processes e+e? → e+e? and μ+μ? have been studied at PETRA using the JADE detector. The data, which were collected at s-values of up to 1300 GeV2 have been analysed in terms of an electro-weak extension of QED to obtain values for the weak vector and axial vector couplings in the lepton sector. The values obtained agree with the predictions of the standard Salam-Weinberg model and the data are further analysed in terms of this model to obtain the limits 0.10 < sin2?w < 0.40 (68% CL). The mass of the neutral weak gauge boson is deduced to be greater than 51 GeV/c2. 相似文献
5.
H. Deden F.J. Hasert W. Krenz D. Lanske J. Morfin M. Pohl K. Schultze L. Welch G. Bertrand-Coremans H. Mulkens J. Sacton W. Van Doninck H. Burmeister I. Danilchenko D. Haidt P. Jobin C. Matteuzzi P. Musset A.J. Segar 《Physics letters. [Part B]》1977,67(4):474-478
New results are presented of an analysis of pictures taken during an exposure of Gargamelle to the CERN ν beam in 1975. In addition to three νμ+N→μ?+e++V0+ hadrons events previously reported, an excess is found of events of the type νμ+N→μ?+e++ hadrons without V0. An analysis of strange particle production in charged current events suggests a possible violation of the ΔS=ΔQ rule. Interpreted in terms of charm production, the data permit an estimate of branching ratios and production rate of charmed particles. A limit is also placed on charmed particle production by neutral currents. 相似文献
6.
W. Lerche M. Pohl M. Dewitt C. Vander Velde-Wilquet P. Vilain D. Haidt C. Matteuzzi J.B.M. Pattison B. Degrange T. Francois P. Van Dam M. Jaffre C. Longuemare C. Pascaud S. Ciampolillo F. Mattioli A. Sconza 《Physics letters. [Part B]》1978,78(4):510-514
A sample of 357 events fitting the reaction ν + p → μ? + p + π+ on free proton is obtained from the Gargamelle neutrino propane experiment at the CERN-PS. The average value of the cross section above 1 GeV is found to be (0.60 ± 0.07) 10?38 cm2. The reaction is dominated by the production of the Δ++(1232) resonance. Results on the Δ++ spin density matrix are given. 相似文献
7.
W. Bartel L. Becker D. Cords R. Felst K. Hagiwara D. Haidt H. Junge G. Knies H. Krehbiel P. Laurikainen R. Meinke B. Naroska J. Olsson D. Schmidt P. Steffen G. Dietrich J. Hagemann S. Yamada 《Physics letters. [Part B]》1985,155(4):288-294
A search was performed for the associated production of two different Higgs bosons via a virtual Z0 in e+e? annihilation (e+e? → h10h20) using the JADE detector at PETRA. This was motivated by the interpretation of the monojet events observed at the CERN p collider as anomalous Z0 decays into two neutral Higgs bosons (h10 and h20), where h10 is stable and escapes detection while h20 decays into hadrons. Single- or di-jet events with large momentum imbalance are then expected at PETRA energies. No evidence for such events was found in our data; this excludes h20 masses in the range of 1 to 21 GeV with 95% CL, if the branching fraction for Z0 → h10h20 is a larger than one half that for . The possibility that the monojets could originate from supersymmetric higgsino production from Z0 decay is also examined. 相似文献
8.
W. Bartel L. Becker C. Bowdery D. Cords R. Felst D. Haidt J. Huttunen H. Junge G. Knies H. Krehbiel P. Laurikainen R. Meinke B. Naroska J. Olsson E. Pietarinen D. Schmidt P. Steffen S. Yamada 《Physics letters. [Part B]》1984,139(4):327-331
We have searched for the supersymmetric partner of the photon, the photino, by investigating two-photon and single photon final states in e+e? collisions. No significant signals were observed, which excludes the existence of the photino in the mass range 0.08–18 GeV/c2 at the 95% confidence level, subject to the assumptions d=(100 GeV)2 and , where d is the supersymmetry breaking scale parameter and is the scalar electron mass. 相似文献
9.
W. Bartel L. Becker D. Cords R. Felst D. Haidt H. Junge G. Knies H. Krehbiel P. Laurikainen K. Meier R. Meinke B. Naroska J. Olsson D. Schmidt P. Steffen G. Dietrich J. Hagemann S. Yamada 《Physics letters. [Part B]》1985,157(4):340-344
Distributions of particles in three-jet events from e+e? → hadrons are compared with different fragmentation schemes, i.e. the Lund string model, independent parton fragmentation and QCD shower models. Effects specific to the string scheme, which have been seen in the data, are also reproduced by QCD shower models if soft gluon interference effects are included. 相似文献
10.
An updated and refined analysis of the structure of the hadronic neutral current in the neutrino-induced deep-inelastic scattering is reported. Starting from a careful treatment of the most recent neutrino charged current data, a reparametrization of the nucleon structure functions is performed including all effects such as QCD evolution, longitudinal structure function, quark mixing, slow rescaling, radiative corrections, and so on. The errors induced by the theoretical approach on the final estimate are conveniently introduced together with their correlations. Starting from all available experimental data concerning both isoscalar and non-isoscalar targer (43 independent experimental results are included in the analysis), through an analytic procedure the four squared chiral couplings are derived: the modelindependent analysis leads to $$\begin{gathered} u_L^2 = 0.1197 \pm 0.0116( \pm 0.0008), \hfill \\ d_L^2 = 0.1785 \pm 0.0119( \pm 0.0035), \hfill \\ u_R^2 = 0.0257 \pm 0.0081( \pm 0.0014), \hfill \\ d_R^2 = 0.0052 \pm 0.0078( \pm 0.0030), \hfill \\ \end{gathered} $$ where the first error comes from the experimental errors affecting the different measurements (with quadratic addition of statistical and systematic errors) and the second one is the theoretical error induced by the uncertainties in the parametrization. A comparison with the standard model is then performed. If ρ=1 is 0.0029 (±0.0024) is obtained for fixedc-quark mass. If the assumption ρ=1 is relaxed, the simultaneous estimate of both parameters leads to sin2 θ W =0.2346±0.0105(±0.0079) and ρ=1.0036±0.0099 (±0.0064). A comparison with the case in which radiative corrections are not included is also considered. Furthermore, constraints on the masses of the charm and top are derived. By using the slow rescaling to describe the threshold effect induced bym c within the minimal standard model,m c =1.54±0.33, is obtained. In an analogous way, starting from the effects induced by them t -dependent terms in the radiative corrections, the upper limitm t <267 (291) GeV (with and without the inclusion of the uncertainties due to the parametrization) at 90% C.L. is found. 相似文献