SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Hahn T) srt2:(2000-2004)"

Sökning: WFRF:(Hahn T) > (2000-2004)

  • Resultat 1-10 av 26
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Abreu, P., et al. (författare)
  • Measurement of the gluon fragmentation function and a comparison of the scaling violation in gluon and quark jets
  • 2000
  • Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 13:4, s. 573-589
  • Tidskriftsartikel (refereegranskat)abstract
    • The fragmentation functions of quarks and gluons are measured in various three-jet topologies in Z decays from the full data set collected with the DELPHI detector at the Z resonance between 1992 and 995. The results at different values of transverse momentum-like scales are compared. A parameterization of the quark and gluon fragmentation functions at a fixed reference scale is given. The quark and gluon fragmentation functions show the predicted pattern of scaling violations. The scaling violation for quark jets as a function of a transverse momentum-like scale is in a good agreement with that observed in lower energy e+e- annihilation experiments. For gluon jets it appears to be significantly stronger. The scale dependences of the gluon and quark fragmentation functions agree with the prediction of the DGLAP evolution equations from which the colour factor ratio CA/CF is measured to be: CA/CF = 2.26 ± 0.09stat. ± 0.06sys. ± 0.12clus.,scale..
  •  
2.
  • Abreu, P., et al. (författare)
  • Study of dimuon production in photon-photon collisions and measurement of QED photon structure functions at LEP
  • 2001
  • Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 19:1, s. 15-28
  • Tidskriftsartikel (refereegranskat)abstract
    • Muon pair production in the process e+e- → e+e- μ+μ- is studied using the data taken at LEP1 (√s ≃ mz) with the DELPHI detector during the years 1992-1995. The corresponding integrated luminosity is 138.5 pb-1. The QED predictions have been tested over the whole Q2 range accessible at LEP1 (from several GeV2/c4 to several hundred GeV2/c4) by comparing experimental distributions with distributions resulting from Monte Carlo simulations using various generators. Selected events are used to extract the leptonic photon structure function Fγ 2. Azimuthal correlations are used to obtain information on additional structure functions, Fγ A and Fγ B, which originate from interference terms of the scattering amplitudes. The measured ratios Fγ A/Fγ 2 and FγB/Fγ 2 are significantly different from zero and consistent with QED predictions.
  •  
3.
  • Adcox, K, et al. (författare)
  • PHENIX detector overview
  • 2003
  • Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 499:2-3, s. 469-479
  • Tidskriftsartikel (refereegranskat)abstract
    • The PHENIX detector is designed to perform a broad study of A-A, p-A, and p-p collisions to investigate nuclear matter under extreme conditions. A wide variety of probes, sensitive to all timescales, are used to study systematic variations with species and energy as well as to measure the spin structure of the nucleon. Designing for the needs of the heavy-ion and polarized-proton programs has produced a detector with unparalleled capabilities. PHENIX measures electron and muon pairs, photons, and hadrons with excellent energy and momentum resolution. The detector consists of a large number of subsystems that are discussed in other papers in this volume. The overall design parameters of the detector are presented. (C) 2002 Elsevier Science B.V. All rights reserved.
  •  
4.
  • Abdallah, J, et al. (författare)
  • Study of inclusive J/psi production in two-photon collisions at LEP II with the DELPHI detector
  • 2003
  • Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 565:1-4, s. 76-86
  • Tidskriftsartikel (refereegranskat)abstract
    • Inclusive J/psi production in photon-photon collisions has been observed at LEP II beam energies. A clear signal from the reaction gammagamma --> J/psi + X is seen. The number of observed N(J/psi --> mu(+)mu(-)) events is 36+/-7 for an integrated luminosity of 617 pb(-1), yielding a cross-section of sigma(J/psi + X) = 45+/-9(stat) +/- 17(syst) pb. Based on a study of the event shapes of different types of gammagamma processes in the PYTHIA program, we conclude that (74+/-22) % of the observed J/psi events are due to 'resolved' photons, the dominant contribution of which is most probably due to the gluon content of the photon. (C) 2003 Published by Elsevier B.V.
  •  
5.
  • Abreu, P., et al. (författare)
  • Search for sleptons in e+e- collisions at √s = 183 to 189 GeV
  • 2001
  • Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 19:1, s. 29-42
  • Tidskriftsartikel (refereegranskat)abstract
    • Data taken by the DELPHI experiment at centre-of-mass energies of 183 GeV and 189 GeV with a total integrated luminosity of 212 pb-1 have been used to search for the supersymmetric partners of the electrons, muons, and taus in the context of the Minimal Supersymmetric Standard Model (MSSM). The decay topologies searched for were the direct decay (ℓ̃ → ℓx̃), producing acoplanar lepton pairs plus missing energy, and the cascade decay (ℓ → ℓx̃0 2 → ℓγx̃0 1), producing acoplanar lepton and photon pairs plus missing energy. The observed number of events is in agreement with Standard Model predictions. The 95% CL excluded mass limits for selectrons, smuons and staus are mẽ ≤ 87 GeV/c2, mμ̃ ≤ 80 GeV/c2 and mτ̃ 75 GeV/c2, respectively, for values of μ=-200 GeV/c2 and tanβ=1.5.
  •  
6.
  • Abdallah, J, et al. (författare)
  • Rapidity-alignment and p(T) compensation of particle pairs in hadronic Z(0) decays
  • 2002
  • Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 533:3-4, s. 243-252
  • Tidskriftsartikel (refereegranskat)abstract
    • Observation is made of rapidity-alignment of K+K- and (p) over barp pairs which results from their asymmetric orientation in rapidity, with respect to the direction from primary quark to antiquark. The K+K- and (p) over barp data are consistent with predictions from the fragmentation string model. However, the (p) over barp data strongly disagree with the conventional implementation of the cluster model. The non-perturbative process of 'gluon splitting to diquarks' has to be incorporated into the cluster model for it to agree with the data. Local conservation of PT between particles nearby in rapidity (i.e., p(T) compensation) is analysed with respect to the thrust direction for pi(+)pi(-), K+K-, and (p) over barp pairs. In this case, the string model provides fair agreement with the data. The cluster model is incompatible with the data for all three particle pairs. The model with its central premiss of isotropically-decaying clusters predicts a p(T) correlation not seen in the data. (C) 2002 Elsevier Science B.V. All rights reserved.
  •  
7.
  • Abdallah, J, et al. (författare)
  • Search for charged Higgs bosons in e(+)e(-) collisions root s=189-202 GeV
  • 2002
  • Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 525:1-2, s. 17-28
  • Tidskriftsartikel (refereegranskat)abstract
    • A search for pair-produced charged Higgs bosons was performed in the high energy data collected by the DELPHI detector at LEP II at centre-of-mass energies from 189 GeV to 202 GeV. The three different final states, taunutaunu, c (s) over bar(c) over bars and c (s) over bar taunu were considered. New methods were applied to reject wrong hadronic jet pairings and for the tau identification, where a discriminator based on tau polarisation and polar angles was used. No excess of data compared to the expected Standard Model processes was observed and the existence of a charged Higgs boson with mass lower than 71.5 GeV/c(2) is excluded at the 95% confidence level. (C) 2002 Published by Elsevier Science B.V.
  •  
8.
  • Abdallah, J, et al. (författare)
  • Searches for neutral Higgs bosons in e(+)e(-), collisions from root s=191.6 to 201.7 GeV
  • 2002
  • Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 23:3, s. 409-435
  • Tidskriftsartikel (refereegranskat)abstract
    • Neutral Higgs bosons of the Standard Model (SM) and the Minimal Supersymmetric Standard Model (MSSM) were searched for in the data collected in 1999 by the DELPHI experiment at centre-of-mass energies between 191.6 and 201.7 GeV with a total integrated luminosity of 228 pb(-1). These analyses, in combination with our results at lower energies, set 95% confidence level lower mass bounds on the Standard Model Higgs boson (107.3 GeV/c(2)) and on the lightest neutral scalar (85.9 GeV/c(2)) and neutral pseudoscalar (86.5 GeV/c(2)) Higgs bosons in representative scans of the MSSM parameter space. An extended scan of the MSSM parameter space was also performed to test the robustness of these limits.
  •  
9.
  • Imanishi, T., et al. (författare)
  • Integrative annotation of 21,037 human genes validated by full-length cDNA clones
  • 2004
  • Ingår i: PLoS biology. - : Public Library of Science (PLoS). - 1544-9173 .- 1545-7885. ; 2:6, s. 856-875
  • Tidskriftsartikel (refereegranskat)abstract
    • The human genome sequence defines our inherent biological potential; the realization of the biology encoded therein requires knowledge of the function of each gene. Currently, our knowledge in this area is still limited. Several lines of investigation have been used to elucidate the structure and function of the genes in the human genome. Even so, gene prediction remains a difficult task, as the varieties of transcripts of a gene may vary to a great extent. We thus performed an exhaustive integrative characterization of 41,118 full-length cDNAs that capture the gene transcripts as complete functional cassettes, providing an unequivocal report of structural and functional diversity at the gene level. Our international collaboration has validated 21,037 human gene candidates by analysis of high-quality full-length cDNA clones through curation using unified criteria. This led to the identification of 5,155 new gene candidates. It also manifested the most reliable way to control the quality of the cDNA clones. We have developed a human gene database, called the H-Invitational Database (H-InvDB; http://www.h-invitational.jp/). It provides the following: integrative annotation of human genes, description of gene structures, details of novel alternative splicing isoforms, non-protein-coding RNAs, functional domains, subcellular localizations, metabolic pathways, predictions of protein three-dimensional structure, mapping of known single nucleotide polymorphisms (SNPs), identification of polymorphic microsatellite repeats within human genes, and comparative results with mouse full-length cDNAs. The H-InvDB analysis has shown that up to 4% of the human genome sequence (National Center for Biotechnology Information build 34 assembly) may contain misassembled or missing regions. We found that 6.5% of the human gene candidates (1,377 loci) did not have a good protein-coding open reading frame, of which 296 loci are strong candidates for non-protein-coding RNA genes. In addition, among 72,027 uniquely mapped SNPs and insertions/deletions localized within human genes, 13,215 nonsynonymous SNPs, 315 nonsense SNPs, and 452 indels occurred in coding regions. Together with 25 polymorphic microsatellite repeats present in coding regions, they may alter protein structure, causing phenotypic effects or resulting in disease. The H-InvDB platform represents a substantial contribution to resources needed for the exploration of human biology and pathology.
  •  
10.
  • Adler, SS, et al. (författare)
  • PHENIX on-line systems
  • 2003
  • Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 499:2-3, s. 560-592
  • Tidskriftsartikel (refereegranskat)abstract
    • The PHENIX On-Line system takes signals from the Front End Modules (FEM) on each detector subsystem for the purpose of generating events for physics analysis. Processing of event data begins when the Data Collection Modules (DCM) receive data via fiber-optic links from the FEMs. The DCMs format and zero suppress the data and generate data packets. These packets go to the Event Builders (EvB) that assemble the events in final form. The Level-1 trigger (LVL1) generates a decision for each beam crossing and eliminates uninteresting events. The FEMs carry out all detector processing of the data so that it is delivered to the DCMs using a standard format. The FEMs also provide buffering for LVL1 trigger processing and DCM data collection. This is carried out using an architecture that is pipelined and deadtimeless. All of this is controlled by the Master Timing System (MTS) that distributes the RHIC clocks. A Level-2 trigger (LVL2) gives additional discrimination. A description of the components and operation of the PHENIX On-Line system is given and the solution to a number of electronic infrastructure problems are discussed. (C) 2002 Elsevier Science B.V. All rights reserved.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-10 av 26

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy