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Journal articleBarate R, Buskulic D, Decamp D, et al., 1998,
Studies of quantum chromodynamics with the ALEPH detector
, Physics Report, Vol: 294, Pages: 1-165, ISSN: 0370-1573Previously published and as yet unpublished QCD results obtained with the ALEPH detector at LEP1 are presented. The unprecedented statistics allows detailed studies of both perturbative and non-perturbative aspects of strong interactions to be carried out using hadronic Z and tau decays. The studies presented include precise determinations of the strong coupling constant, tests of its flavour independence, tests of the SU(3) gauge structure of QCD, study of coherence effects, and measurements of single-particle inclusive distributions and two-particle correlations for many identified baryons and mesons. © 1998 Elsevier Science B.V.
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Journal articleAraüjo HM, 1998,
Study of bialkali photocathodes below room temperature in the uv/vuv region
, IEEE Transactions on Nuclear Science, Vol: 45, Pages: 542-549, ISSN: 0018-9499Two photomultiplier tubes with bialkali photocathodes and fused silica windows (2″ Philips XP2020Q and 1-1/8" Hamamatsu R1668) were studied between room temperature and -160°C, illuminated in dc mode in the UV/VUV wavelength range. The photomultipliers were operated as diodes, with direct measurement of the current of photoelectrons, in order to study in detail the effects associated to the photocathode. The influence of light intensity, applied voltage and illuminated area on the response as a function of temperature were investigated. The increase of the electrical resistivity of the emissive layer upon cooling proved to be responsible for a loss of linearity of the photocathode response, leading ultimately to the complete absence of signal at low temperature. A simplified model is presented that accounts for some experimental results. An unexpected increase of response below room temperature was also found at 170 nm. © 1998 IEEE.
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Journal articleAbreu P, Adam W, Adye T, et al., 1998,
Charged particle multiplicity in e<SUP>+</SUP>e<SUP>-</SUP>→q(q)over-bar events at 161 and 172 GeV and from the decay of the W boson
, PHYSICS LETTERS B, Vol: 416, Pages: 233-246, ISSN: 0370-2693- Cite
- Citations: 36
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Journal articleAckerstaff K, Alexander G, Allison J, et al., 1998,
An upper limit for the τ-neutrino mass from τ → 5π±vτ decays
, European Physical Journal C, Vol: 5, Pages: 229-237, ISSN: 1434-6044An upper limit for the τ-neutrino mass has been determined from the decay τ → 5π<sup>±</sup>v<inf>τ</inf> using data collected with the OPAL detector from 1991 to 1995 in e<sup>+</sup>e<sup>-</sup> collisions at √s ≈ Mz. A limit of 43.2 MeV at 95% CL is obtained using a two-dimensional method in the 5π invariant mass and energy distribution from 22 selected events. Combining this result with OPAL's previously published measurement using τ<sup>+</sup> τ<sup>-</sup> → 3h<sup>±</sup>v̄<inf>τ</inf> + 3h∓v<inf>τ</inf> decays, a new combined limit of m<inf>vτ</inf> < 27.6 MeV (95% CL) is obtained.
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Journal articleAckerstaff K, Alexander G, Allison J, et al., 1998,
Search for anomalous production of di-lepton events with missing transverse momentum in e+e- collisions at √S = 161 and 172 GeV
, European Physical Journal C, Vol: 4, Pages: 47-74, ISSN: 1434-6044Events containing two charged leptons and significant missing transverse momentum are selected from a data sample corresponding to a total integrated luminosity of 20.6 pb<sup>-1</sup> at centre-of-mass energies of 161 GeV and 172 GeV. The observed number of events, four at 161 GeV and nine at 172 GeV, is consistent with the number expected from Standard Model processes, predominantly arising from W<sup>+</sup>W<sup>-1</sup> production with each W decaying leptonically. This topology is also an experimental signature for the pair production of new particles that decay to a charged lepton accompanied by one or more invisible particles Further event selection criteria are described that optimise the sensitivity to particular new physics channels No evidence for new phenomena is observed and limits on the production of scalar charged lepton pairs and other new particles are presented.
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Journal articleAckerstaff K, Alexander G, Allison J, et al., 1998,
A measurement of the B0s lifetime using reconstructed D-s mesons
, European Physical Journal C, Vol: 2, Pages: 407-416, ISSN: 1434-6044We report a measurement of the B<sup>0</sup><inf>s</inf> meson lifetime from B<sup>0</sup><inf>s</inf> → D<sup>-</sup><inf>s</inf>X decays, where D<sup>-</sup><inf>s</inf> mesons are reconstructed in the D<sup>-</sup><inf>s</inf> → φπ<sup>-</sup> and D<sup>-</sup><inf>s</inf> → K*<sup>0</sup>K<sup>-</sup> decay channels. From approximately 3.7 million hadronic Z<sup>0</sup> decays recorded by the OPAL detector at LEP a sample is selected containing 911 ± 83 candidates, of which 519 ± 136 are estimated to be from B<sup>0</sup><inf>s</inf> meson decays. Fitting the distribution of the distance from the beam spot to the decay vertex of the D<sup>-</sup><inf>s</inf> candidates with an unbinned likelihood function we measure π(B<sup>0</sup><inf>s</inf>) = 1 72<sup>+0.20+0.18</sup><inf>-0.19-0.17</inf> ps, where the errors are statistical and systematic, respectively.
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Journal articleAckerstaff K, Alexander G, Allison J, et al., 1998,
Investigation of CP violation in B0 → J/ψKS0 decays at LEP
, European Physical Journal C, Vol: 5, Pages: 379-388, ISSN: 1434-6044An investigation of CP violation was performed using a total of 24 candidates for B<sup>0</sup> → J/ψK<sup>0</sup><inf>S</inf> decay, with a purity of about 60%. These events were selected from 4.4 million hadronic Z<sup>0</sup> decays recorded by the OPAL detector at LEP. An analysis procedure, involving techniques to reconstruct the proper decay times and tag the produced b-flavours, B<sup>0</sup> or B̄<sup>0</sup>, has been developed to allow a first direct study of the time dependent CP asymmetry that, in the Standard Model, is sin 2β. The result is sin 2β = 3.2<sup>+1.8</sup> <inf>-2.0</inf> ± 0.5 where the first error is statistical and the second systematic. This result is used to determine probabilities for different values of sin 2β in the physical region from -1 to +1.
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Journal articleAcciarri M, Adriani O, Aguilar-Benitez M, et al., 1998,
Measurement of the B0d - B̄0d oscillation frequency
, European Physical Journal C, Vol: 5, Pages: 195-203, ISSN: 1434-6044Time-dependent B<sup>0</sup>-B̄<sup>0</sup> mixing is studied using about two million hadronic Z decays registered by L3 in 1994 and 1995. For this study three techniques are used. Tagging of the b-quark charge at decay time is performed by identifying leptons from semileptonic B decays. The flavour of the b quark at production time is determined from the charge of the lepton in the opposite hemisphere or by using a jet-charge technique. The proper time of the B-particle decay is obtained by reconstructing the production and decay vertices or by a measurement of the lepton impact parameter. The combined result for the frequency of B<sup>0</sup><inf>d</inf> meson oscillations is Δm<inf>d</inf> = 0.444 ± 0.040 ps<sup>-1</sup>.
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Journal articleAcciarri M, Adriani O, Aguilar-Benitez M, et al., 1998,
Measurement of the average lifetime of b-hadrons in Z decays
, PHYSICS LETTERS B, Vol: 416, Pages: 220-232, ISSN: 0370-2693- Author Web Link
- Cite
- Citations: 11
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Journal articleAckerstaff K, Alexander G, Allison J, et al., 1998,
Search for a massive Di-photon resonance at √s=91-172 GeV
, EUROPEAN PHYSICAL JOURNAL C, Vol: 1, Pages: 31-43, ISSN: 1434-6044- Cite
- Citations: 16
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Journal articleAckerstaff K, Alexander G, Allison J, et al., 1998,
Search for unstable heavy and excited leptons in e<SUP>+</SUP>e<SUP>-</SUP> collisions at √s=170-172 GeV
, EUROPEAN PHYSICAL JOURNAL C, Vol: 1, Pages: 45-64, ISSN: 1434-6044- Cite
- Citations: 23
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Journal articleBarate R, Buskulic D, Decamp D, et al., 1998,
Three-prong τ decays with charged kaons
, EUROPEAN PHYSICAL JOURNAL C, Vol: 1, Pages: 65-79, ISSN: 1434-6044- Cite
- Citations: 35
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Journal articleAbreu P, Adam W, Adye T, et al., 1998,
Search for charginos, neutralinos and gravitinos at LEP
, EUROPEAN PHYSICAL JOURNAL C, Vol: 1, Pages: 1-20, ISSN: 1434-6044- Author Web Link
- Cite
- Citations: 41
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Journal articleAckerstaff K, Alexander G, Allison J, et al., 1998,
Multi-photon final states in e<SUP>+</SUP>e<SUP>-</SUP> collisions at √s=130-172 GeV
, EUROPEAN PHYSICAL JOURNAL C, Vol: 1, Pages: 21-30, ISSN: 1434-6044- Cite
- Citations: 12
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Conference paperAli T, Sumner TJ, Quenby JJ, et al., 1998,
New limits on the WIMP Cold Dark Matter interaction cross section from the UK experiment
, Singapore, 1st international workshop on particle physics and the early universe (cosmo-97) SEP 15-19, 1997 AMBLESIDE, ENGLAND, Publisher: World Scientific Publ Co Pte Ltd, Pages: 172-178 -
Conference paperRowan-Robinson M, Oliver SJ, Mann RG, et al., 1998,
The ISO Survey of the Hubble Deep Field
, The Hubble Deep Field, Publisher: Cambridge University Press -
Conference paperSumner TJ, Sidher SD, Quenby JJ, et al., 1998,
Fluctuations in the soft x-ray background, probably of galactic halo origin
, The Local Bubble and Beyond - IAU Colloquium 166, Publisher: Springer-Verlag, Pages: 333-336 -
Journal articleVirdee TS, Britton DI, Cameron W, et al., 1998,
CMS technical design report: the Tracker project
, CERN/LHCC, Pages: 1-6 -
Journal articleBreitweg J, Sideris D, 1998,
Diffractive dijet cross-sections in photoproduction at HERA
, Eur.Phys.J., Vol: C5, Pages: 41-56 -
Journal articleBreitweg J, Sideris D, 1998,
Measurement of elastic Upsilon photoproduction at HERA
, Phys.Lett.B., Vol: 437, Pages: 432-444 -
Journal articleLeader E, 1998,
An exact sum rule for transversely polarised DIS
, International Journal of Modern Physics A, Vol: 13 -
Journal articleSeez C, Davies GJ, Virdee TS, 1998,
Beam tests of lead tungstate crystal matrices and a silicon strip preshower detector for the CMS electromagnetic calorimeter
, Nuclear Instruments & Methods in Physics Research Section A- Accelerators Spectrometers Detectors and Associated Equipment, Vol: 412, Pages: 223-237 -
Journal articleHall G, Etemadi A, 1998,
The CMS silicon tracker at LHC
, Nuclear Instruments & Methods in Physics Research Section A- Accelerators Spectrometers Detectors and Associated Equipment, Vol: 409, Pages: 105-111 -
Journal articleSideris D, 1998,
Measurement of the diffractive structure function F2(D(4)) at HERA
, Eur.Phys.J., Vol: C1, Pages: 81-96 -
Conference paperAli T, Sumner TJ, Quenby JJ, et al., 1998,
New limits on the WIMP Cold Dark Matter interaction cross section from the UK experiment
, Singapore, 1st international workshop on particle physics and the early universe (cosmo-97) SEP 15-19, 1997 AMBLESIDE, ENGLAND, Publisher: World Scientific Publ Co Pte Ltd, Pages: 172-178 -
Journal articleBreitweg J, Sideris D, 1998,
High E(T) inclusive jet cross-sections in photoproduction at HERA
, Eur.Phys.J., Vol: C4, Pages: 591-606 -
Journal articleAraujo HM, Chepel VY, Lopes MI, et al., 1998,
Study of bialkali photocathodes below room temperature in the UV/VUV region
, Nuclear Science, IEEE Transactions on Nuclear Science, Vol: 45, Pages: 542-549 -
Journal articleFisher PH, Uchida Y, 1998,
Measurement of the invisible W width
, Journal of High Energy Physics, Pages: 019-019, ISSN: 1126-6708 -
Journal articleBreitweg J, Sideris D, 1998,
Event shape analysis of deep inelastic scattering events with a large rapidity gap at HERA
, Phys.Lett.B., Vol: 421, Pages: 368-384 -
Journal articleHall G, Payne RG, 1998,
Amplifiers and electronics
, Instrumentation in Elementary Particle Physics - the Vii Icfa School, Pages: 283-312, ISSN: 0094-243X
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