| 1. |
- Schael, S, et al.
(författare)
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Precision electroweak measurements on the Z resonance
- 2006
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
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Forskningsöversikt (refereegranskat)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
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| 2. |
- Abreu, P, et al.
(författare)
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A search for eta '(c) production in photon-photon fusion at LEP
- 1998
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Ingår i: PHYSICS LETTERS B. - : ELSEVIER SCIENCE BV. - 0370-2693. ; 441:1-4, s. 479-490
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- A search for the production of the eta(c)' meson, the first radial excitation of the ground state of charmonium eta(c)(2980), in the photon-photon fusion reaction at LEP has been performed using the data collected by the DELPHI detector during 1992-1996.
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| 3. |
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| 4. |
- Abreu, P, et al.
(författare)
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Measurement of vertical bar V-cs vertical bar using W decays at LEP2
- 1998
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Ingår i: PHYSICS LETTERS B. - : ELSEVIER SCIENCE BV. - 0370-2693. ; 439:1-2, s. 209-224
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Decays of W+/- bosons, produced at LEP2, have been used to measure the \V-cs\ element of the Cabibbo-Kobayashi-Maskawa matrix. Values for \V-cs\ were extracted both from the measured hadronic branching ratio of W+/- decays and by tagging the flavour of ha
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| 5. |
- Abreu, P, et al.
(författare)
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pi(+/-), K-+/-, p and (p)over-bar production in Z(0)-> q(q)over-bar, Z(0)-> b(b)over-bar, Z(0)-> u(u)over-bar,d(d)over-bar,s(s)over-bar
- 1998
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Ingår i: EUROPEAN PHYSICAL JOURNAL C. - : SPRINGER VERLAG. - 1434-6044. ; 5:4, s. 585-620
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The DELPHI experiment at LEP uses Ring Imaging Cherenkov detectors for particle identification. The good understanding of the RICH detectors allows the identification of charged pions, kaons and protons, covering the full momentum range from 0.7 < p < 45.
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| 6. |
- Abreu, P, et al.
(författare)
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Search for Leptoquarks and FCNC in e(+)(e)(-) annihilations root s = 183 GeV
- 1999
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Ingår i: PHYSICS LETTERS B. - : ELSEVIER SCIENCE BV. - 0370-2693. ; 446:1, s. 62-74
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- A search fur events with one jet and at most one isolated lepton used data taken at LEP-2 by the DELPHI detector. These data were accumulated at a center-of-mass energy of 183 GeV and correspond to an integrated luminosity of 47.7 pb(-1) Production of sin
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