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Sökning: WFRF:(Ek P.) > (2000-2004)

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1.
  • Abreu, P, et al. (författare)
  • b-tagging in DELPHI at LEP
  • 2004
  • Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 32:2, s. 185-208
  • Tidskriftsartikel (refereegranskat)abstract
    • The standard method used for tagging b-hadrons in the DELPHI experiment at the CERN LEP Collider is discussed in detail. The main ingredient of b-tagging is the impact parameters of tracks, which relies mostly on the vertex detector. Additional information, such as the mass of particles associated to a secondary vertex, significantly improves the selection efficiency and the background suppression. The paper describes various discriminating variables used for the tagging and the procedure of their combination. In addition, applications of b-tagging to some physics analyses, which depend crucially on the performance and reliability of b-tagging, are described briefly.
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2.
  • 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.
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3.
  • 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.
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4.
  • 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.
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5.
  • 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.
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6.
  • Abdallah, J, et al. (författare)
  • Search for supersymmetric particles in light gravitino scenarios and sleptons NLSP
  • 2003
  • Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 27:2, s. 153-172
  • Tidskriftsartikel (refereegranskat)abstract
    • A search for sleptons, neutralinos, charginos, sgoldstinos and heavy stable charged sleptons in the context of scenarios where the lightest supersymmetric particle is the gravitino, is presented. Data collected during 2000 with the DELPHI detector at centre-of-mass energies from 204 to 208 GeV were analysed and combined with all the data collected from 1995 to 1999 at lower energies. No evidence for the production of sleptons, neutralinos and charginos has been found, therefore new limits on the mass of these supersymmetric particles and on the model parameter space are set. The search for heavy stable charged sleptons also updates the stable sleptons mass limit. The absence of evidence for sgoldstino production allows limits to be set on its mass and on the scale of supersymmetry breaking.
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7.
  • Abdallah, J, et al. (författare)
  • A study of the energy evolution of event shape distributions and their means with the DELPHI detector at LEP
  • 2003
  • Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 29:3, s. 285-312
  • Tidskriftsartikel (refereegranskat)abstract
    • Infrared and collinear safe event shape distributions and their mean values are determined in e(+)e(-) collisions at centre-of-mass energies between 45 and 202GeV. A phenomenological analysis based on power correction models including hadron mass effects for both differential distributions and mean values is presented. Using power corrections, alpha(s) is extracted from the mean values and shapes. In an alternative approach, renormalisation group invariance (RGI) is used as an explicit constraint, leading to a consistent description of mean values without the need for sizeable power corrections. The QCD beta-function is precisely measured using this approach. From the DELPHI data on Thrust, including data from low energy experiments, one finds beta(0) = 7.86 +/- 0.32 for the one loop coefficient of the beta-function or, assuming QCD, n(f) = 4.75 +/- 0.44 for the number of active flavours. These values agree well with the QCD expectation of beta(0) = 7.67 and n(f) 5. A direct measurement of the full logarithmic energy slope excludes light gluinos with a mass below 5GeV.
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8.
  • Abdallah, J, et al. (författare)
  • Final results from DELPHI on the searches for SM and MSSM neutral Higgs bosons
  • 2004
  • Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 32:2, s. 145-183
  • Tidskriftsartikel (refereegranskat)abstract
    • These final results from DELPHI searches for the Standard Model (SM) Higgs boson, together with benchmark scans of the Minimal Supersymmetric Standard Model (MSSM) neutral Higgs bosons, used data taken at centre-of-mass energies between 200 and 209 GeV with a total integrated luminosity of 224 pb(-1). The data from 192 to 202 GeV are reanalysed with improved b-tagging for MSSM final states decaying to four b-quarks. The 95% confidence level lower mass bound on the Standard Model Higgs boson is 114.1 GeV/c(2). Limits are also given on the lightest scalar and pseudo-scalar Higgs bosons of the MSSM.
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9.
  • Abdallah, J, et al. (författare)
  • Inclusive b decays to wrong sign charmed mesons
  • 2003
  • Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 561:1-2, s. 26-40
  • Tidskriftsartikel (refereegranskat)abstract
    • The production of wrong sign charmed mesons b --> (D) over bar X-(s), D-(s) = (D-0, D+, D-s), is studied using the data collected by the DELPHI experiment in the years 1994 and 1995. Charmed mesons in Z --> b (b) over bar events are exclusively reconstructed by searching for the decays D-0 --> K(-)pi(+), D+ --> K(-)pi(+)pi(+) and D-s(+) --> phipi(+) --> K(+)K(-)pi(+). The wrong sign contribution is extracted by using two discriminant variables: the charge of the b-quark at decay time, estimated from the charges of identified particles, and the momentum of the charmed meson in the rest frame of the b-hadron. The inclusive branching fractions of b-hadrons into wrong sign charm mesons are measured to be: B(b --> (D) over bar X-0) + B(b --> D-X) = (9.3 +/- 1.7(stat) +/- 1.3(syst) +/- 0.4(B))%, B(b --> Ds-X) = (10.1 +/- 1.0(stat) +/- 0.6(syst) +/- 2.8(B))% where the first error is statistical, the second and third errors are systematic. (C) 2003 Published by Elsevier Science B.V.
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10.
  • Abdallah, J, et al. (författare)
  • Measurement of inclusive f(1) (1285) and f(1) (1420) production in Z decays with the DELPHI detector
  • 2003
  • Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 569:3-4, s. 129-139
  • Tidskriftsartikel (refereegranskat)abstract
    • DELPHI results are presented on the inclusive production of two (K(K) over bar π)(0) states in the mass region 1.2-1.6 GeV/c(2) in hadronic Z decays at LEP I. The measured masses (widths) are 1274 +/- 6 MeV/c(2) (29 +/- 12 MeV/c(2)) and 1426 +/- 6 MeV/c(2) (51 +/- 14 MeV/c(2)), respectively. A partial-wave analysis of the (K(K) over bar π)(0) system shows that the first peak is consistent with the I-G (J(PC)) = 0(+)(1(++))/(0(-+))a(0)(980)pi and the second with the I-G (J(PC)) = 0(+)(1(++))K*(892)(K) over bar + c.c. assignments. The total hadronic production rates per hadronic Z decay are (0.165 +/- 0.051) and (0.056 +/- 0.012), respectively. These measurements are consistent with the two states being the f(1) (1285) and f(1) (1420) mesons. (C) 2003 Published by Elsevier B.V.
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11.
  • Abdallah, J, et al. (författare)
  • Measurement of the e(+)e(-)-> W+W- gamma cross-section and limits on anomalous quartic gauge couplings with DELPHI
  • 2003
  • Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 31:2, s. 139-147
  • Tidskriftsartikel (refereegranskat)abstract
    • W(+)W(-)gamma production at LEP2 is studied using data collected with the DELPHI detector at centre-of-mass energies between 189 GeV and 209 GeV, corresponding to an integrated luminosity of about 600 pb(-1). Cross-sections are measured for the production of W+W- with a hard, central and isolated photon in the final state, and are found to be compatible with the Standard Model prediction. The photon energy spectra are used to derive limits on anomalous contributions to the W(+)W(-)Z(o)gamma and W(+)W(-)gammagamma vertices.
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12.
  • Abdallah, J, et al. (författare)
  • Measurement of the Lambda(0)(b) decay form factor
  • 2004
  • Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 585:1-2, s. 63-84
  • Tidskriftsartikel (refereegranskat)abstract
    • The form factor of A(o)(b) baryons is estimated using 3.46 x 10(6) hadronic Z decays collected by the DELPM experiment between 1992 and 1995. Charmed A(c)(+) baryons fully reconstructed in the pK(-)pi(+), pK(o)(s), and Api(+)pi(+)pi(-) modes, are associated to a c S lepton with opposite charge in order to select A(o)(b) --> A(c)(+)l(-)v(l) decays. From a combined likelihood and event rate fit to the b C distribution of the Isgur-Wise variable w, and using the Heavy Quark Effective Theory (HQET), the slope of the b-baryon form factor is measured to be p(2)=2.03+/-0.46(stat)(-1.00)(+0.72)(syst). The exclusive semileptonic branching fraction Br(A(b)(o) --> A(c)(+)l(-)v(l)) can be derived from p(2) and is found to be (5.0(-0.8)(+1.1)(stat)(-1.2)(+1.6) (syst))%. Limits on other branching fractions are also obtained. (C) 2004 Published by Elsevier B.V.
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13.
  • Abdallah, J, et al. (författare)
  • Search for an LSP gluino at LEP with the DELPHI detector
  • 2003
  • Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 26:4, s. 505-525
  • Tidskriftsartikel (refereegranskat)abstract
    • In some supersymmetric models, the gluino ((g) over tilde) is predicted to be light and stable. In that case, it would hadronize to form R-hadrons. In these models, the missing energy signature of the lightest supersymmetric particle is no longer valid, even if R-parity is conserved. Therefore, such a gluino is not constrained by hadron collider results, which looked for the decay (g) over tilde --> q (q) over bar(χ) over tilde (0)(1). Data collected by the DELPHI detector in 1994 at 91.2 GeV have been analysed to search for q (q) over bar(gg) over tilde events. No deviation from Standard Model predictions is observed and a gluino mass between 2 and 18 GeV/c(2) is excluded at the 95% confidence level in these models. Then, R-hadrons produced in the squark decays were searched for in the data collected by DELPHI at the centre-of-mass energies of 189 to 208 GeV, corresponding to an overall integrated luminosity of 609 pb(-1). The observed number of events is in agreement with the Standard Model predictions. Limits at 95% confidence level are derived on the squark masses from the excluded regions in the plane (m((q) over tilde1),m((g) over bar)): m((t) over tilde1) > 90 GeV/c(2) and m((b) over tilde1) > 96 GeV/c(2) for purely left squarks. m((t) over tilde1) > 87 GeV/c(2) and m((b) over tilde1) > 82 GeV/c(2) independent of the mixing angle.
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14.
  • Abdallah, J, et al. (författare)
  • Search for B-s(0)-(B-s(0))over-bar oscillations and a measurement of B-d(0)-(B-d(0))over-bar oscillations using events with an inclusively reconstructed vertex
  • 2003
  • Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 28:2, s. 155-173
  • Tidskriftsartikel (refereegranskat)abstract
    • Neutral B meson oscillations in the B-s(0) - <(B-s(0))over bar>, and B-d(0) - <(B-d(0))over bar> systems were studied using a sample of about 4.0 million hadronic Z decays recorded by the DELPHI detector between 1992 and 2000. Events with a high transverse momentum lepton were removed and a sample of 770 k events with an inclusively reconstructed vertex was selected. The mass difference between the two physical states in the B-d(0) - <(B-d(0))over bar>system was measured to be: Deltam(d) = (0.531 +/- 0.025(stat.) +/- 0.007(syst.))ps(-1). The following limit on the width difference of these states was also obtained: DeltaGamma(Bd)/Gamma(Bd) < 0.18 at 95% CL. As no evidence for B-s(0) -<(B-s(0))over bar> oscillations was found, a limit on the mass difference of the two physical states was given:, Deltam(s) > 5.0 ps(-1) at 95% CL. The corresponding sensitivity of this analysis is equal to 6.6 ps(-1).
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15.
  • Abdallah, J, et al. (författare)
  • Search for resonant (nu)over-tilde production at root s=183 to 208 GeV
  • 2003
  • Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 28:1, s. 15-26
  • Tidskriftsartikel (refereegranskat)abstract
    • Searches for resonant (ν) over tilde production in e(+)e(-) collisions under the assumption that R-parity is not conserved and that the dominant R-parity violating coupling is lambda(121) or lambda(131) used data recorded by DELPHI in 1997 to 2000 at centre-of-mass energies of 183 to 208 GeV. No deviation from the Standard Model was observed. Upper limits are given for the lambda(121) and lambda(131) couplings as a function of the sneutrino mass and total width. The limits are especially stringent for sneutrino masses equal to the centre-of-mass energies with the highest integrated luminosities recorded.
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16.
  • Abdallah, J, et al. (författare)
  • Searches for invisibly decaying Higgs bosonswith the DELPHI detector at LEP
  • 2004
  • Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 32:4, s. 475-492
  • Tidskriftsartikel (refereegranskat)abstract
    • Searches for HZ production with the Higgs boson decaying into an invisible final state were performed using the data collected by the DELPHI experiment at centre-of-mass energies between 188 GeV and 209 GeV. Both hadronic and leptonic final states of the Z boson were analysed. In addition to the search for a heavy Higgs boson, a dedicated search for a light Higgs boson down to 40 GeV/c(2) was performed. No signal was found. Assuming the Standard Model HZ production cross-section, the mass limit for invisibly decaying Higgs bosons is 112.1 GeV/c(2) at 95% confidence level. An interpretation in the Minimal Supersymmetric extension of the Standard Model (MSSM) and in a Majoron model is also given.
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17.
  • Abdallah, J, et al. (författare)
  • Searches for supersymmetric particles in e(+)e(-) collisions up to 208 GeV and interpretation of the results within the MSSM
  • 2003
  • Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 31:4, s. 421-479
  • Tidskriftsartikel (refereegranskat)abstract
    • DELPHI data collected at centre-of-mass energies up to 208 GeV have been analysed to search for charginos, neutralinos and sfermions in the framework of the Minimal Supersymmetric Standard Model (MSSM) with R-parity conservation. No evidence for a signal was found in any of the channels. The results of each search were used to derive limits on production cross-sections and particle masses. In addition, the combined result of all searches excludes regions in the parameter space of the constrained MSSM, leading to limits on the mass of the Lightest Supersymmetric Particle and other supersymmetric particles.
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18.
  • Abdallah, J, et al. (författare)
  • The eta(c)(2980) formation in two-photon collisions at LEP energies
  • 2003
  • Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 31:4, s. 481-489
  • Tidskriftsartikel (refereegranskat)abstract
    • eta(c)(2980) production in gammagamma interactions has been detected via its decays into K(s)(0)K(-/+)pi(-/+), K+K-K+K- and K(+)K(-)pi(+)pi(-) in the data taken with the DELPHI detector at LEP1 and LEP2 energies. The two-photon radiative width averaged over all observed decay channels is Gammagammagamma=13.9+/-2.0(stat.)+/-1.4(syst.)+/-2.7 (BR) keV. No direct decay channel eta(c)-->pi(+)pi(-)pi(+)pi(-) has been observed. An upper limit Gamma(gammagamma)<5.5 keV at 95% confidence level has been evaluated for this decay mode.
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19.
  • Abdallah, J, et al. (författare)
  • ZZ production in e(+) e(-) interactions at root s=183-209 GeV
  • 2003
  • Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 30:4, s. 447-466
  • Tidskriftsartikel (refereegranskat)abstract
    • Measurements of on-shell ZZ production are described, using data from the DELPHI experiment at LEP in e(+)e(-) collisions at centre-of-mass energies between 183 and 209 GeV, corresponding to an integrated luminosity of about 665 pb(-1). Results obtained in each of the final states q (q) over barq (q) over bar, nu(ν) over barq (q) over bar, mu(+)mu(-) q (q) over bar, e(+)e(-) r(+)r(-) q (q) over bar, l(+)l(-)l(+)l(-), and nu(ν) over barl(+)l(-) (with l = e, mu) are presented. The measured production cross-sections are consistent with the Standard Model expectations. These results update and supersede those already published at 183 and 189 GeV.
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20.
  • Abdallah, J, et al. (författare)
  • Searches for neutral Higgs bosons in extended models
  • 2004
  • Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 38:1, s. 1-28
  • Tidskriftsartikel (refereegranskat)abstract
    • Searches for neutral Higgs bosons produced at LEP in association with Z bosons, in pairs and in the Yukawa process are presented in this paper. Higgs boson decays into b quarks, tau leptons, or other Higgs bosons are considered, giving rise to four-b, four-b+jets, six-b and four-tau final states, as well as mixed modes with b quarks and tau leptons. The whole mass domain kinematically accessible at LEP in these topologies is searched. The analysed data set covers both the LEP1 and LEP2 energy ranges and exploits most of the luminosity recorded by the DELPHI experiment. No convincing evidence for a signal is found, and results are presented in the form of mass-dependent upper bounds on coupling factors (in units of model-independent reference cross-sections) for all processes, allowing interpretation of the data in a large class of models.
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21.
  • Abdallah, J, et al. (författare)
  • Search for doubly charged Higgs bosons at LEP2
  • 2003
  • Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 552:3-4, s. 127-137
  • Tidskriftsartikel (refereegranskat)abstract
    • A search for pair-produced doubly charged Higgs bosons has been performed using the data collected by the DELPHI detector at LEP at centre-of-mass energies between 189 and 209 GeV. No excess is observed in the data with respect to the Standard Model background. A lower limit for the mass of 97.3 GeV/c(2) at the 95% confidence level has been set for doubly charged Higgs bosons in left-right symmetric models for any value of the Yukawa coupling between the Higgs bosons and the tau leptons. (C) 2002 Published by Elsevier Science B.V.
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22.
  • Abdallah, J, et al. (författare)
  • A measurement of the branching fractions of the b-quark into charged and neutral b-hadrons
  • 2003
  • Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 576:1-2, s. 29-42
  • Tidskriftsartikel (refereegranskat)abstract
    • The production fractions of charged and neutral b-hadrons in b-quark events from Z(0) decays have been measured with the DELPHI detector at LEP. An algorithm has been developed, based on a neural network, to estimate the charge of the weakly-decaying b-hadron by distinguishing its decay products from particles produced at the primary vertex. From the data taken in the years 1994 and 1995, the fraction of (b) over bar -quarks fragmenting into positively charged weakly-decaying b-hadrons has been measured to be: f(+) = (42.09+/-0.82(stat)+/-0.89(syst))%. Subtracting the rates for charged Xi(b)(+) and Omega(b)(+) baryons gives the production fraction of B+ mesons: f(Bu) = (40.99+/-0.82(stat)+/-1.11 (syst)) %.
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23.
  • Abdallah, J, et al. (författare)
  • Search for single top production via FCNC at LEP at root s=189-208 GeV
  • 2004
  • Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 590:1-2, s. 21-34
  • Tidskriftsartikel (refereegranskat)abstract
    • A search for single top production (e(+)e(-) --> t (c) over bar) via flavour changing neutral currents (FCNC) was performed using the data taken by the DELPHI detector at LEP2. The data analyzed have been accumulated at center-of-mass energies ranging from 189 to 208 GeV. Limits at 95% confidence level were obtained on the anomalous coupling parameters kappa(gamma) and kappa(Z). (C) 2004 Published by Elsevier B.V.
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24.
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26.
  • Andersson, G, et al. (författare)
  • TRACP as an osteopontin phosphatase
  • 2003
  • Ingår i: Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research. - : Wiley. - 0884-0431. ; 18:10, s. 1912-1915
  • Tidskriftsartikel (refereegranskat)
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27.
  • Axelsson, P., et al. (författare)
  • Influence of alkali profiling in birch kraft pulping on QPQP bleachability
  • 2004
  • Ingår i: Nordic Pulp & Paper Research Journal. - : Walter de Gruyter GmbH. - 0283-2631 .- 2000-0669. ; 19:1, s. 37-43
  • Tidskriftsartikel (refereegranskat)abstract
    • The influence of different aspects of alkali profiling in the kraft cook on QPQP bleachability of oxygen-delignified birch pulp was investigated. The use of a levelled-out alkali profile was compared to a conventional, and different modifications to the levelled-out alkali profile, like alkali charge, degree of delignification and amount of dissolved organic substance and ionic strength in the cooking liquor were studied. The alkali profile itself was found to have a significant effect where a levelled-out alkali profile showed a superior bleachability compared to a conventional one. The bleachability improved with an increased alkali charge towards the end of the cook, a high kappa number after cooking or by a cooking liquor exchange in order to decrease the amount of dissolved organic substance and the ionic strength towards the end of the cook. When a levelled-out alkali profile was used, the bleachability correlated well with the light-absorption of the lignin in the unbleached pulp, where a pulp with a brighter lignin consumed less peroxide in the QPQP sequence, for the pulp to reach 89% brightness.
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28.
  • Axelsson, P., et al. (författare)
  • The influence of alkali charge and temperature in the kraft cook on the QPQP bleachability and the kappa number composition of birch pulp
  • 2002
  • Ingår i: Nordic Pulp & Paper Research Journal. - : Walter de Gruyter GmbH. - 0283-2631 .- 2000-0669. ; 17:3, s. 206-212
  • Tidskriftsartikel (refereegranskat)abstract
    • The main objective of this investigation was to study how the alkali charge and the temperature in the kraft cook influence the QPQP bleachability of oxygen-delignified birch pulp. The bleachability was evaluated as the normalised consumption of bleaching chemicals required to reach a certain light absorption coefficient of the pulp. All the pulps had a kappa number of about 17 after the cook and a kappa number of about 10 after oxygen delignification. The alkali charge significantly affected the bleachability and the best bleachability was obtained for an intermediate level alkali charge ([HO-](initial)=1,35 mol/L, corresponding to an effective alkali charge of 21.6% on wood). An increase in cooking temperature gave only a slight increase in bleachability. The contributions to the kappa number of lignin, hexenuronic acids (HexA) and other non-lignin structures were also investigated. Lignin contributed to about 60% of the kappa number in pulps after the cook, to about 40% in pulps after the oxygen delignification, and to about 30% after QPQP bleaching. Hexenuronic acids contributed between 3.7 to 4.7 kappa number units in all pulps, which makes them the largest contributors to the kappa number in oxygen-delignified and QPQP bleached pulps. Other non-lignin structures, were contributing about 3 kappa number units in pulps after the cook, but decreased to less than I kappa number unit after QPQP bleaching. No great differences in the composition of the kappa number could be seen between pulps produced under different pulping conditions, except that there was a somewhat lower hexenuronic acid content in the pulps produced with the highest alkali charge or at the highest cooking temperature.
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29.
  • Ek, I, et al. (författare)
  • A unique defect in the regulation of visceral fat cell lipolysis in the polycystic ovary syndrome as an early link to insulin resistance
  • 2002
  • Ingår i: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 51:2, s. 484-492
  • Tidskriftsartikel (refereegranskat)abstract
    • The etiology of polycystic ovary syndrome (PCOS) is unknown. However, PCOS has a strong resemblance to the insulin resistance (metabolic) syndrome, where an increased rate of visceral fat cell lipolysis is believed to play a pathophysiological role. We hypothesized that primary defects in visceral lipolysis might also exist in PCOS. Ten young, nonobese, and otherwise healthy PCOS women were compared with 13 matched control women. In vitro lipolysis regulation and stoichiometric properties of the final step in lipolysis activation, namely the protein kinase A (PKA)-hormone sensitive lipase (HSL) complex, were investigated in isolated visceral (i.e., omental) fat cells. Body fat distribution and circulating levels of insulin, glucose, and lipids were normal in PCOS women. However, in vivo insulin sensitivity was slightly decreased (P = 0.03). Catecholamine-induced adipocyte lipolysis was markedly (i.e., about twofold) increased in PCOS women due to changes at the postreceptor level, although there was no change in the antilipolytic properties of visceral fat cells. Western blot analyses of visceral adipose tissue showed twofold increased levels of the catalytic and the regulatory la components of PKA. In contrast, the regulatory RIIbeta component of PKA was almost 50% decreased in visceral adipose tissue in PCOS women. Recent studies on genetically modified mice have shown that a similar transition in the regulatory PKA units induces an increased lipolytic response to catecholamines. Further analysis showed that the level of HSL-short, an enzymatically inactive splice form of HSL, was decreased in PCOS (P < 0.01). The altered lipolysis in PCOS is different from that observed in visceral fat cells in the insulin resistance syndrome that occurs at the level of adrenergic receptors. We concluded that increased catecholamine-induced lipolysis in visceral fat cells may be due to unique alterations in the stoichiometric properties of the adipose PKA-HSL holoenzymes. This could be an early and possibly primary lipolysis defect in PCOS.
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30.
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31.
  • Ek, P, et al. (författare)
  • Exogenous protein kinases A and C, but not endogenous prostasome-associated protein kinase, phosphorylate semenogelins I and II from human semen
  • 2002
  • Ingår i: Journal of Andrology. - 0196-3635. ; 23:6, s. 806-814
  • Tidskriftsartikel (refereegranskat)abstract
    • Semenogelins I and II are the quantitatively dominating proteins in human semen. They comprise the major part of the sperm-entrapping gel formed at ejaculation, which subsequently liquefies due to proteolysis of the gel-forming proteins by prostate-specific antigen (PSA). The mechanism behind gel formation and its physiological significance is not known. We have studied phosphorylation and dephosphorylation of human semenogelins. Both were phosphorylated by protein kinases A and C (PKA and PKC, respectively) at a rate about 5 times less than that of histone. For PKA, incorporated ( P)phosphate into semenogelin approached a maximum above 1 mol/mol. Corresponding values for phosphorylation of the semenogelins with PKC were greater than 10. There was no change in the sensitivity of phosphosemenogelins to proteolysis by PSA. Serine (PKA) and serine and threonine (PKC) were the phosphate-accepting amino acid residues, and all incorporated (P-32)phosphate could be removed from the semenogelins with human acid phosphatase. Nil or very little phosphate could be detected in purified semenogelins isolated from seminal plasma. In vivo, about half the protein kinase activity in seminal plasma was bound to prostasomes. PKA but not PKC purified from prostasomes could phosphorylate specific substrates, but they could phosphorylate either of the semenogelins.
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32.
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33.
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34.
  • Hedenus, P, et al. (författare)
  • Characterisation of instantaneous water absorption properties of pharmaceutical excipients
  • 2000
  • Ingår i: INTERNATIONAL JOURNAL OF PHARMACEUTICS. - 0378-5173. ; 202:1-2, s. 141-149
  • Tidskriftsartikel (refereegranskat)abstract
    • Powders absorb water by both capillary imbibition and swelling. The capillary process is almost instantaneous but swelling occurs over. a period of time. An isothermal transient ionic current technique was used in this study to characterise the instantane
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35.
  • Hedenus, P, et al. (författare)
  • Characterisation of instantaneous water absorption properties of pharmaceutical excipients.
  • 2000
  • Ingår i: International Journal of Pharmaceutics. - 0378-5173 .- 1873-3476. ; 202:1-2, s. 141-9
  • Tidskriftsartikel (refereegranskat)abstract
    • Powders absorb water by both capillary imbibition and swelling. The capillary process is almost instantaneous but swelling occurs over a period of time. An isothermal transient ionic current technique was used in this study to characterise the instantaneous absorption properties (rate and capacity) of a few selected pharmaceutical excipients. The results indicate that the instantaneous and long term water absorption properties of pharmaceutical powders can differ considerably. The rate of instantaneous water absorption appears to correlate with the total surface area while the absorption capacity correlates more with the porosity of the powder.
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36.
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37.
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38.
  • Johansson, S., et al. (författare)
  • Small, novel proteins from the mistletoe Phoradendron tomentosum exhibit highly selective cytotoxicity to human breast cancer cells
  • 2003
  • Ingår i: Cellular and Molecular Life Sciences (CMLS). - : Springer Science and Business Media LLC. - 1420-682X .- 1420-9071. ; 60:1, s. 165-175
  • Tidskriftsartikel (refereegranskat)abstract
    • Four novel proteins (phoratoxins C-F) have been isolated from the North American mistletoe Phoradendron tomentosum. The amino acid sequences of these phoratoxins were determined unambiguously using a combination of Edman degradation and trypsin enzymatic digestion, and by electrospray ionization tandem mass spectrometry sequencing. Phoratoxins C, E and F consist of 46 amino acid residues; and phoratoxin D of 41. All proteins had six cysteines, similar to the earlier described phoratoxins A and B, which are thionins. The cytotoxicity of each protein was evaluated in a human cell line panel that represented several cytotoxic drug-resistance mechanisms. For the half-maximal inhibitory concentrations (IC50 values) of the different cell lines in the panel, correlation with those of standard drugs was low. The most potent cytotoxic phoratoxin C was further tested on primary cultures of human tumor cells from patients. The solid tumor samples from breast cancer cells were 18 times more sensitive to phoratoxin C than the tested hematological tumor samples.
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40.
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41.
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42.
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43.
  • Louka, A S, et al. (författare)
  • The IL12B gene does not confer susceptibility to coeliac disease.
  • 2002
  • Ingår i: Tissue antigens. - 0001-2815. ; 59:1, s. 70-2
  • Tidskriftsartikel (refereegranskat)abstract
    • Coeliac disease (CD) is a chronic inflammatory disorder where dietary gluten is not tolerated. In the lesion there are gluten reactive T cells predominantly secreting gamma-interferon. Both HLA and non-HLA genes contribute to CD susceptibility. Interleukin-12 (IL-12) regulates gamma-interferon production. The IL12B gene is located in a region (5q31.1-33.1) where there is evidence for linkage with CD. Allele 1 of an IL12B 3'UTR single-nucleotide polymorphism leads to increased expression of IL-12, and was recently implicated in susceptibility for type 1 diabetes (T1D). We found no evidence for association of allele 1 to CD by the transmission/disequilibrium test or case-control approach. No increased frequency was observed in patients belonging to families where the disease was linked to markers on chromosome 5q. Unlike T1D, allele 1 does not appear to confer susceptibility to CD.
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44.
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45.
  • Mattsson, MS, et al. (författare)
  • A new method of characterising liquid uptake within particles over short time periods
  • 2000
  • Ingår i: INTERNATIONAL JOURNAL OF PHARMACEUTICS. - 0378-5173. ; 199:2, s. 179-185
  • Tidskriftsartikel (refereegranskat)abstract
    • A method of measuring both the capacity and rate of absorption of liquid by powders of small particles over short time periods (of the order of a few seconds or less) is presented. The method is based on the measurement of the isothermal transient ionic c
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46.
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47.
  • Normann, EK, et al. (författare)
  • Treatment of acute neonatal bacterial conjunctivitis: a comparison of fucidic acid to chloramphenicol eye drops
  • 2002
  • Ingår i: Acta Ophthalmologica Scandinavica. - : Wiley. - 1395-3907. ; 80:2, s. 183-187
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: To compare the clinical and bacteriological effects of fucidic acid (Fucithalmic(R): 1.0%) and chloramphenicol (Minims(R): 0.5%) eye drops in neonates with a clinical diagnosis of acute conjunctivitis of suspected bacterial origin. Methods: A total of 456 newborns with gestational age > 32 weeks with acute conjunctivitis of suspected bacterial origin acquired within the first 28 days of life were included in the study. They were randomly assigned to a 7-day treatment with eye drops using either fucidic acid (1.0%) (Fucithalmic(R)) applied or chloramphenicol (0.5%) (Minims(R) Chloramphenicol) applied twice per day six times per day. The subjects were followed up with two visits (on days 1 and 8) and by telephone 2 weeks after the end of treatment. Results: Eighty-nine per cent of the neonates treated with Fucithalmic(R) were cured, compared to 87.9% of those treated with Minims(R) Chloramphenicol (n.s). The drug was used as instructed in 90.7% of patients treated with Fucithalmic(R) and in 78.0% of those treated with Minims(R) Chloramphenicol (P < 0.001). Conclusion: Treating neonatal conjunctivitis with fucidic acid is easier than with chloramphenicol and is equally effective.
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48.
  • Persson, E., et al. (författare)
  • Serotypes and clinical manifestations of invasive group B streptococcal infections in western Sweden 1998-2001
  • 2004
  • Ingår i: Clin Microbiol Infect. - : Elsevier BV. - 1198-743X. ; 10:9, s. 791-6
  • Tidskriftsartikel (refereegranskat)abstract
    • This study monitored the serotypes of Streptococcus agalactiae (group B streptococcus; GBS) isolated from invasive infections in western Sweden and investigated possible relationships between serotype, age and clinical manifestations. Invasive GBS isolates were collected prospectively during 1998-2001 at six laboratories, covering two counties with a population of 1.8 million, and were serotyped by coagglutination. Clinical data were obtained from hospital notes. In total, 161 invasive strains (50 from neonates and infants aged < 3 months, and 111 from adults) were serotyped. The commonest serotypes from neonates and infants were serotypes III (60%), V (22%) and Ia (10%), and from adults were serotypes V (42%) and III (25%). Serotype V had doubled in frequency among both children and adults compared to a previous study from the same area in 1988-1997. Most (80%) of the adults had an underlying medical condition. No relationship was found between serotype and clinical manifestations. However, the study demonstrated the importance of active surveillance of GBS serotypes and the difficulties of formulating a multivalent polysaccharide conjugate vaccine against GBS.
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