| 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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Measurement of the inclusive charmless and double-charm B branching ratios
- 1998
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Ingår i: PHYSICS LETTERS B. - : ELSEVIER SCIENCE BV. - 0370-2693. ; 426:1-2, s. 193-206
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The DELPHI experiment at LEP has measured the inclusive charmless B hadron decay branching ratio, the B branching ratio into two charmed particles, and the total number of charmed particles per B decay, using the hadronic Z data taken between 1992 and 199
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| 3. |
- 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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| 4. |
- Abreu, P, et al.
(författare)
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A study of the hadronic resonance structure in the decay tau -> 3 pi nu(tau)
- 1998
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Ingår i: PHYSICS LETTERS B. - : ELSEVIER SCIENCE BV. - 0370-2693. ; 426:3-4, s. 411-427
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The hadronic structure of the decay of the tau lepton to three charged particles, tau --> 3 pi nu(tau), is studied using data collected by the DELPHI detector at LEP between 1992 and 1995. The invariant mass of the 3 pi system, m(3 pi), is fitted using th
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| 5. |
- Abreu, P, et al.
(författare)
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Cross-sections and leptonic forward-backward asymmetries from the Z(0) running of LEP
- 2000
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Ingår i: EUROPEAN PHYSICAL JOURNAL C. - : SPRINGER-VERLAG. - 1434-6044. ; 16:3, s. 371-405
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Tidskriftsartikel (refereegranskat)abstract
- During 1993 and 1995 LEP was run at 3 energies near the Z(0) peak in order to give improved measurements of the mass and width of the resonance. During 1994, LEP operated only at the Z(0) peak. In total DELPHI accumulated data corresponding to an integrat
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| 6. |
- Abreu, P, et al.
(författare)
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First evidence for a charm radial excitation, D-*'
- 1998
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Ingår i: PHYSICS LETTERS B. - : ELSEVIER SCIENCE BV. - 0370-2693. ; 426:1-2, s. 231-242
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Using D*+ mesons exclusively reconstructed in the DELPHI detector at LEP, an excess of 66 +/- 14(stat.) events is observed in the D(*+)pi(+)pi(-) final state with a mass of 2637 +/- 2(stat.) +/- 6(syst.) MeV/c(2) and a full width smaller than 15 MeV/c(2)
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| 7. |
- Abreu, P, et al.
(författare)
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Investigation of the splitting of quark and gluon jets
- 1998
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Ingår i: EUROPEAN PHYSICAL JOURNAL C. - : SPRINGER VERLAG. - 1434-6044. ; 4:1, s. 1-17
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The splitting processes in identified quark and gluon jets are investigated using longitudinal and transverse observables. The jets are selected from symmetric three-jet events measured in Z decays with the DELPHI detector in 1991-1994. Gluon jets are ide
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| 8. |
- Abreu, P, et al.
(författare)
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m(b) at M-Z
- 1998
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Ingår i: PHYSICS LETTERS B. - : ELSEVIER SCIENCE BV. - 0370-2693. ; 418:3-4, s. 430-442
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The value of the Lr quark, mass at the M-Z scale defined in the <(MS)over bar> renormalization scheme, m(b)(M-Z), was determined using 2.8 million hadronic Z decays collected during 1992-1994 by the DELPHI detector to be m(b)(M-Z) = 2.67 +/- 0.25 (stat.)
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| 9. |
- Abreu, P, et al.
(författare)
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Measurement of B-d(0)-(B-d(0))over-bar oscillations
- 1997
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Ingår i: ZEITSCHRIFT FUR PHYSIK C-PARTICLES AND FIELDS. - : SPRINGER VERLAG. - 0170-9739. ; 76:4, s. 579-598
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- B-d(0) meson oscillations are measured in hadronic Z(0) decays using the charge of a lepton or the mean charge of an event hemisphere to sign the presence of a b or a (b) over bar quark when it is produced, and using the charge of a lepton emitted at larg
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| 10. |
- Abreu, P, et al.
(författare)
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Measurement of the charged particle multiplicity of weakly decaying B hadrons
- 1998
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Ingår i: PHYSICS LETTERS B. - : ELSEVIER SCIENCE BV. - 0370-2693. ; 425:3-4, s. 399-412
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- From the Z decays recorded in 1994 and 1995 by the DELPHI detector at LEP, the charged particle multiplicity of weakly decaying B hadrons was measured to be: 4.97 +/- 0.03 +/- 0.06 excluding the K-o and Lambda decay products. (C) 1998 Published by Elsevie
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