| 1. |
- Abdallah, J, et al.
(författare)
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Charged particle multiplicity in three-jet events and two-gluon systems
- 2005
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; C:44, s. 311-331
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Tidskriftsartikel (refereegranskat)abstract
- The charged particle multiplicity in hadronic three-jet events from Z decays is investigated. The topology dependence of the event multiplicity is found to be well described by a modified leading logarithmic prediction. A parameter fit of the prediction to the data yields a measurement of the colour factor ratio C-A/C-F with the result C-A/C-F = 2.261 +/- 0.014(stat). +/- 0.036(exp). +/- 0-066(theo). in agreement with the SU(3) expectation of QCD. The quark-related contribution to the event multiplicity is subtracted from the three-jet event multiplicity resulting in a measurement of the multiplicity of two-gluon colour-singlet states over a wide energy range. The ratios r = N-gg(s)/Ng (g) over bar (s) of the gluon and quark multiplicities and r((1)) = N'(gg)(s)/N'g (g) over bar (s) of their derivatives are compared with perturbative calculations. While a good agreement between calculations and data is observed for r((1)), larger deviations are found for r indicating that non-perturbative effects are more important for r than for r((1)).
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| 2. |
- Abdallah, J, et al.
(författare)
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Production of Xi(0)(c) and Xi(b) in Z decays and lifetime measurement of Xi(b)
- 2005
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; C:44, s. 299-309
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Tidskriftsartikel (refereegranskat)abstract
- The charmed strange baryon Xi(c)(0) was searched for in the decay channel Xi(c)(0) -> Xi(-)pi(+), and the beauty strange baryon Xi(b) in the inclusive channel Xi(b) -> Xi(-)l(-)(nu) over barX, using the 3.5 million hadronic Z events collected by the DELPHI experiment in the years 1992-1995. The Xi(-) was reconstructed through the decay AT, using a constrained fit method for cascade decays. An iterative discriminant analysis was used for the Xi(c)(0) and Xi(b) selection. The production rates were measured to be f(Xi c)(0) x BR(Xi(c)(0) -> Xi(-)pi(+) = (4.7 +/- 1.4(stat.) +/- 1.1(syst.)) x 10(-4) per hadronic Z decay, and BR(b -> Xi(b))xBR(Xi(b) -> Xi(-)l(-)X) = (3.0 +/- 1.0(stat.) +/- 0.3(syst.)) x 10(-4) for each lepton species (electron or muon). The lifetime of the Xi(b) baryon was measured to be tau(Xi b) = 1.45(-0.43)(+0.55)(stat.)+/- 0.13(syst.) ps. A combination with the previous DELPHI lifetime measurement gives tau(Xi b) = 1.48(-0.31)(+0.40)(stat.)+/- 0.12(syst.) ps.
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| 3. |
- Abreau, P, et al.
(författare)
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Photon events with missing energy at root s=183 to 189 GeV
- 2000
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Ingår i: EUROPEAN PHYSICAL JOURNAL C. - : SPRINGER-VERLAG. - 1434-6044. ; 17:1, s. 53-65
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Tidskriftsartikel (refereegranskat)abstract
- The production of single photons has been studied in the reaction e(+)e(-) --> gamma +invisible particles at centre-of-mass energies of 183 GeV and 189 GeV. A previously published analysis of events with multiphoton final states accompanied by missing ene
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| 4. |
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| 5. |
- Abreu, P, et al.
(författare)
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A measurement of alpha(s) from the scaling violation in e(+)e(-) annihilation
- 1997
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Ingår i: PHYSICS LETTERS B. - : ELSEVIER SCIENCE BV. - 0370-2693. ; 398:1-2, s. 194-206
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The hadronic fragmentation functions of the various quark flavours and of gluons are measured in a study of the inclusive hadron production from Z(0) decays with the DELPHI detector and are compared with the fragmentation functions measured elsewhere at e
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| 6. |
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| 7. |
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| 8. |
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| 9. |
- Abreu, P, et al.
(författare)
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A measurement of the Tau topological branching ratios
- 2001
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Ingår i: EUROPEAN PHYSICAL JOURNAL C. - : SPRINGER-VERLAG. - 1434-6044. ; 20:4, s. 617-637
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Tidskriftsartikel (refereegranskat)abstract
- Using data collected in the DELPHI detector at LEP-1, measurements of the inclusive T branching ratios for decay modes containing one, three, or five charged particles have been performed, giving the following results: B-1 equivalent to B T- (particle)(-)
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| 10. |
- Abreu, P, et al.
(författare)
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A precise measurement of the B-d(0) meson lifetime using a new technique
- 1997
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Ingår i: ZEITSCHRIFT FUR PHYSIK C-PARTICLES AND FIELDS. - : SPRINGER VERLAG. - 0170-9739. ; 74:1, s. 19-32
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- From data recorded by DELPHI between 1991 and 1994, which corresponds to 3.2 million hadronic Z(0) decays, a measurement of the <(B-d(0))over bar> meson lifetime, based on the inclusive reconstruction of 3520 +/- 150 semileptonic decays of the type <(B-d(
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