| 1. |
- Aad, G., et al.
(author)
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Commissioning of the ATLAS Muon Spectrometer with cosmic rays
- 2010
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In: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 70:3, s. 875-916
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Journal article (peer-reviewed)abstract
- The ATLAS detector at the Large Hadron Collider has collected several hundred million cosmic ray events during 2008 and 2009. These data were used to commission the Muon Spectrometer and to study the performance of the trigger and tracking chambers, their alignment, the detector control system, the data acquisition and the analysis programs. We present the performance in the relevant parameters that determine the quality of the muon measurement. We discuss the single element efficiency, resolution and noise rates, the calibration method of the detector response and of the alignment system, the track reconstruction efficiency and the momentum measurement. The results show that the detector is close to the design performance and that the Muon Spectrometer is ready to detect muons produced in high energy proton-proton collisions.
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| 2. |
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| 3. |
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| 4. |
- Aad, G., et al.
(author)
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Studies of the performance of the ATLAS detector using cosmic-ray muons
- 2011
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In: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 71:3
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Journal article (peer-reviewed)abstract
- Muons from cosmic-ray interactions in the atmosphere provide a high-statistics source of particles that can be used to study the performance and calibration of the ATLAS detector. Cosmic-ray muons can penetrate to the cavern and deposit energy in all detector subsystems. Such events have played an important role in the commissioning of the detector since the start of the installation phase in 2005 and were particularly important for understanding the detector performance in the time prior to the arrival of the first LHC beams. Global cosmic-ray runs were undertaken in both 2008 and 2009 and these data have been used through to the early phases of collision data-taking as a tool for calibration, alignment and detector monitoring. These large datasets have also been used for detector performance studies, including investigations that rely on the combined performance of different subsystems. This paper presents the results of performance studies related to combined tracking, lepton identification and the reconstruction of jets and missing transverse energy. Results are compared to expectations based on a cosmic-ray event generator and a full simulation of the detector response.
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| 5. |
- Aad, G., et al.
(author)
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The ATLAS Inner Detector commissioning and calibration
- 2010
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In: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 70:3, s. 787-821
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Journal article (peer-reviewed)abstract
- The ATLAS Inner Detector is a composite tracking system consisting of silicon pixels, silicon strips and straw tubes in a 2 T magnetic field. Its installation was completed in August 2008 and the detector took part in data-taking with single LHC beams and cosmic rays. The initial detector operation, hardware commissioning and in-situ calibrations are described. Tracking performance has been measured with 7.6 million cosmic-ray events, collected using a tracking trigger and reconstructed with modular pattern-recognition and fitting software. The intrinsic hit efficiency and tracking trigger efficiencies are close to 100%. Lorentz angle measurements for both electrons and holes, specific energy-loss calibration and transition radiation turn-on measurements have been performed. Different alignment techniques have been used to reconstruct the detector geometry. After the initial alignment, a transverse impact parameter resolution of 22.1 +/- 0.9 mu m and a relative momentum resolution sigma (p) /p=(4.83 +/- 0.16)x10(-4) GeV(-1)xp (T) have been measured for high momentum tracks.
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| 6. |
- Aad, G., et al.
(author)
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The ATLAS Simulation Infrastructure
- 2010
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In: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 70:3, s. 823-874
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Journal article (peer-reviewed)abstract
- The simulation software for the ATLAS Experiment at the Large Hadron Collider is being used for large-scale production of events on the LHC Computing Grid. This simulation requires many components, from the generators that simulate particle collisions, through packages simulating the response of the various detectors and triggers. All of these components come together under the ATLAS simulation infrastructure. In this paper, that infrastructure is discussed, including that supporting the detector description, interfacing the event generation, and combining the GEANT4 simulation of the response of the individual detectors. Also described are the tools allowing the software validation, performance testing, and the validation of the simulated output against known physics processes.
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| 7. |
- Abdallah, J., et al.
(author)
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Study of leading hadrons in gluon and quark fragmentation
- 2006
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In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 643:3-4, s. 147-157
-
Journal article (peer-reviewed)abstract
- The study of quark jets in e(+)e(-) reactions at LEP has demonstrated that the hadronisation process is reproduced well by the Lund string model. However. our understanding of gluon fragmentation is less complete. In this study enriched quark and gluon jet samples of different purities are selected in three-jet events from hadronic decays of the Z collected by the DELPHI experiment in the LEP runs during 1994 and 1995. The leading systems of the two kinds of jets are defined by requiring a rapidity gap and their sum of charges is studied. An excess of leading systems with total charge zero is found for gluon jets in all cases, when compared to Monte Carlo simulations with JETSET (with and without Bose-Einstein correlations included) and ARIADNE. The corresponding leading systems of quark jets do not exhibit such an excess. The influence of the gap size and of the gluon purity on the effect is studied and a concentration of the excess of neutral leading systems at low invariant masses (less than or similar to 2 GeV/c(2)) is observed, indicating that gluon jets might have an additional hitherto undetected fragmentation mode via a two-gluon system. This could be an indication of a possible production of gluonic states as predicted by QCD.
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| 8. |
- Schael, S., et al.
(author)
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Electroweak measurements in electron positron collisions at W-boson-pair energies at LEP
- 2013
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In: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 532:4, s. 119-244
-
Research review (peer-reviewed)abstract
- Electroweak measurements performed with data taken at the electron positron collider LEP at CERN from 1995 to 2000 are reported. The combined data set considered in this report corresponds to a total luminosity of about 3 fb(-1) collected by the four LEP experiments ALEPH, DELPHI, 13 and OPAL, at centre-of-mass energies ranging from 130 GeV to 209 GeV. Combining the published results of the four LEP experiments, the measurements include total and differential cross-sections in photon-pair, fermion-pair and four-fermion production, the latter resulting from both double-resonant WW and ZZ production as well as singly resonant production. Total and differential cross-sections are measured precisely, providing a stringent test of the Standard Model at centre-of-mass energies never explored before in electron positron collisions. Final-state interaction effects in four-fermion production, such as those arising from colour reconnection and Bose Einstein correlations between the two W decay systems arising in WW production, are searched for and upper limits on the strength of possible effects are obtained. The data are used to determine fundamental properties of the W boson and the electroweak theory. Among others, the mass and width of the W boson, m(w) and Gamma(w), the branching fraction of W decays to hadrons, B(W -> had), and the trilinear gauge-boson self-couplings g(1)(Z), K-gamma and lambda(gamma), are determined to be: m(w) = 80.376 +/- 0.033 GeV Gamma(w) = 2.195 +/- 0.083 GeV B(W -> had) = 67.41 +/- 0.27% g(1)(Z) = 0.984(-0.020)(+0.018) K-gamma - 0.982 +/- 0.042 lambda(gamma) = 0.022 +/- 0.019. (C) 2013 Elsevier B.V. All rights reserved.
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| 9. |
- Aad, G., et al.
(author)
-
- 2011
-
Journal article (peer-reviewed)
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| 10. |
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| 11. |
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| 12. |
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| 13. |
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| 14. |
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| 15. |
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| 16. |
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| 17. |
- Aad, G., et al.
(author)
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Readiness of the ATLAS Tile Calorimeter for LHC collisions
- 2010
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In: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 70:4, s. 1193-1236
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Journal article (peer-reviewed)abstract
- The Tile hadronic calorimeter of the ATLAS detector has undergone extensive testing in the experimental hall since its installation in late 2005. The readout, control and calibration systems have been fully operational since 2007 and the detector has successfully collected data from the LHC single beams in 2008 and first collisions in 2009. This paper gives an overview of the Tile Calorimeter performance as measured using random triggers, calibration data, data from cosmic ray muons and single beam data. The detector operation status, noise characteristics and performance of the calibration systems are presented, as well as the validation of the timing and energy calibration carried out with minimum ionising cosmic ray muons data. The calibration systems' precision is well below the design value of 1%. The determination of the global energy scale was performed with an uncertainty of 4%.
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| 18. |
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| 19. |
- Abdallah et al., DELPHI Collaboration: J, et al.
(author)
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Study of double-tagged γγ events at LEPII
- 2006
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In: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 46:3, s. 559-568
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Journal article (peer-reviewed)
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| 20. |
- Abdallah, J., et al.
(author)
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A measurement of the tau hadronic branching ratios
- 2006
-
In: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 46:1, s. 1-26
-
Journal article (peer-reviewed)abstract
- The exclusive and semi-exclusive branching ratios of the tau lepton hadronic decay modes (h(-)upsilon(tau), h(-)pi(0)upsilon(tau), h(-)pi(0)pi(0)upsilon(tau), h(-) >= 2 pi(0)nu(tau), 2h(-)h(+)upsilon(tau), 2h(-)h(+)>= 2 pi(0)upsilon(tau), 3h(-)2h(+)upsilon(tau) and 3h(-)2h(+) >= 1 pi(0)upsilon(tau)) were measured with data from the DELPHI detector at LEP.
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| 21. |
- Abdallah, J., et al.
(author)
-
A study of b(b)over-bar production in e(+)e(-) collisions at root s=130-207 GeV
- 2009
-
In: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 60:1, s. 1-15
-
Journal article (peer-reviewed)abstract
- Measurements are presented of R-b, the ratio of the b (b) over bar cross-section to the q (q) over bar cross-section in e(+)e(-) collisions, and the forward-backward asymmetry A(FB)(b) at twelve energy points in the range root s = 130-207 GeV. These results are found to be consistent with the Standard Model expectations. The measurements are used to set limits on new physics scenarios involving contact interactions.
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| 22. |
- Abdallah, J., et al.
(author)
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A study of the b-quark fragmentation function with the DELPHI detector at LEP I and an averaged distribution obtained at the Z Pole
- 2011
-
In: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 71:2, s. 1557-
-
Journal article (peer-reviewed)abstract
- The nature of b-quark jet hadronisation has been investigated using data taken at the Z peak by the DELPHI detector at LEP. Two complementary methods are used to reconstruct the energy of weakly decaying b-hadrons, E-B(weak). The average value of x(B)(weak) = E-B(weak)/E-beam is measured to be 0.699 +/- 0.011. The resulting x(B)(weak) distribution is then analysed in the framework of two choices for the perturbative contribution (parton shower and Next to Leading Log QCD calculation) in order to extract measurements of the non-perturbative contribution to be used in studies of b-hadron production in other experimental environments than LEP. In the parton shower framework, data favour the Lund model ansatz and corresponding values of its parameters have been determined within PYTHIA 6.156 from DELPHI data: a = 1.84(-0.21)(+0.23) and b = 0.642(-0.063)(+0.073) GeV-2, with a correlation factor rho = 92.2%. Combining the data on the b-quark fragmentation distributions with those obtained at the Z peak by ALEPH, OPAL and SLD, the average value of x(B)(weak) is found to be 0.7092 +/- 0.0025 and the non-perturbative fragmentation component is extracted. Using the combined distribution, a better determination of the Lund parameters is also obtained: a = 1.48(-0.10)(+0.11) and b = 0.509(-0.023)(+0.024) GeV-2, with a correlation factor rho = 92.6%.
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| 23. |
- Abdallah, J, et al.
(author)
-
Correlations between polarisation states of W particles in the reaction e(-)e(+)-> W-W+ at LEP2 energies 189-209 GeV
- 2009
-
In: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 63:4, s. 611-623
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Journal article (peer-reviewed)abstract
- In a study of the reaction e(-)e(+)-> W-W+ with the DELPHI detector, the probabilities of the two W particles occurring in the joint polarisation states transverse-transverse (T T), longitudinal-transverse plus transverse-longitudinal (LT) and longitudinal-longitudinal (LL) have been determined using the final states WW -> lvq (q) over bar (l = e, mu). The two-particle joint polarisation probabilities, i.e. the spin density matrix elements rho T T, rho LT, rho LL, are measured as functions of the W- production angle, theta(W-), at an average reaction energy of 198.2 GeV. Averaged over all cos.W-, the following joint probabilities are obtained: (rho) over barT T = (67 +/- 8)%, (rho) over barL T = (30 +/- 8)%, (rho) over barL T = (3 +/- 7)%. These results are in agreement with the Standard Model predictions of 63.0%, 28.9% and 8.1%, respectively. The related polarisation cross-sections sigma(TT), sigma(LT) and sigma(LL) are also presented.
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| 24. |
- Abdallah, J, et al.
(author)
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Determination of heavy quark non-perturbative parametersfrom spectral moments in semileptonic B decays
- 2006
-
In: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 45:1, s. 35-59
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Journal article (peer-reviewed)abstract
- Moments of the hadronic invariant mass and of the lepton energy spectra in semileptonic B decays have been determined with the data recorded by the DELPHI detector at LEP. From measurements of the inclusive b-hadron semileptonic decays, and imposing constraints from other measurements on b- and c-quark masses, the first three moments of the lepton energy distribution and of the hadronic mass distribution, have been used to determine parameters which enter into the extraction of vertical bar V-cb vertical bar from the measurement of the inclusive b-hadron semileptonic decay width. The values obtained in the kinetic scheme are: m(b)(1 GeV) = 4.591 +/- 0.062 +/- 0.039 +/- 0.005 GeV/c(2), m(c)(1 GeV) = 1.170 +/- 0.093 +/- 0.055 +/- 0.005 GeV/c(2), m(pi)(2) (1 GeV) = 0.399 +/- 0.048 +/- 0.034 +/- 0.087 GeV2, (p) over tilde (3)(D) = 0.053 +/- 0.017 +/- 0.011 +/- 0.026 GeV3, and include corrections at order 1/m(b)(3). Using these results, and present measurements of the inclusive semileptonic decay partial width of b-hadrons at LEP, an accurate determination of vertical bar V-cb vertical bar is obtained: vertical bar V-cb vertical bar = 0.0421 x (1 +/- 0.014 (meas center dot) +/- 0.014 (fit) +/- 0.015 (th center dot)).
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| 25. |
- Abdallah, J., et al.
(author)
-
Evidence for an excess of soft photons in hadronic decays of Z(0)
- 2006
-
In: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 47:2, s. 273-294
-
Journal article (peer-reviewed)abstract
- Soft photons inside hadronic jets converted in front of the DELPHI main tracker (TPC) in events of qq disintegrations of the Z(0) were studied in the kinematic range 0.2 < E-y < I GeV and transverse momentum with respect to the closest jet direction P-T < 80 MeV/c. A clear excess of photons in the experimental data as compared to the Monte Carlo predictions is observed. This excess (uncorrected for the photon detection efficiency) is (1.17 +/- 0.06 +/- 0.27) x 10(-3) gamma/jet in the specified kinematic region, while the expected level of the inner hadronic bremsstrahlung (which is not included in the Monte Carlo) is (0.340 +/- 0.001 +/- 0.038) X 10(-3) gamma/jet. The ratio of the excess to the predicted bremsstrahlung rate is then (3.4 +/- 0.2 +/- 0.8), which is similar in strength to the anomalous soft photon signal observed in fixed target experiments with hadronic beams.
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| 26. |
- Abdallah, J, et al.
(author)
-
Inclusive single-particle production in two-photon collisions at LEP II with the DELPHI detector
- 2009
-
In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 678:5, s. 444-449
-
Journal article (peer-reviewed)abstract
- A study of the inclusive charged hadron production in two-photon collisions is described. The data were collected with the DELPHI detector at LEP II. Results on the inclusive single-particle p(T) distribution and the differential charged hadrons d sigma/dp(T) cross-section are presented and compared to the predictions of perturbative NLO QCD calculations and to published results. (C) 2009 Elsevier B.V. All rights reserved.
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| 27. |
- Abdallah, J., et al.
(author)
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Masses, lifetimes and production rates of Xi(-) and Xi(+) at LEP 1
- 2006
-
In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 639:3-4, s. 179-191
-
Journal article (peer-reviewed)abstract
- Measurements of the Xi(-) and (Xi) over bar (+) masses, mass differences, lifetimes and lifetime differences are presented. The (Xi) over bar (+) sample used is much larger than those used previously for such measurements. In addition, the S production rates in Z -> b (b) over bar and Z -> q (q) over bar events are compared and the position xi* of the maximum of the distribution in Z -> q (q) over bar events is measured.
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| 28. |
- Abdallah, J., et al.
(author)
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Measurement and interpretation of fermion-pair production at LEP energies above the Z resonance
- 2006
-
In: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 45:3, s. 589-632
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Journal article (peer-reviewed)abstract
- This paper presents DELPHI measurements and interpretations of cross-sections, forward-backward asymmetries, and angular distributions, for the e(+)e(-) -> f (f) over bar process for centre-of-mass energies above the Z resonance, from root s similar to 130-207 GeV at the LEP collider. The measurements are consistent with the predictions of the Standard Model and are used to study a variety of models including the S-Matrix ansatz for e(+)e(-) -> f (f) over bar scattering and several models which include physics beyond the Standard Model: the exchange of Z' bosons, contact interactions between fermions, the exchange of gravitons in large extra dimensions and the exchange of (v) over tilde in R-parity violating supersymmetry.
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| 29. |
- Abdallah, J., et al.
(author)
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Measurements of CP-conserving trilinear gauge boson couplings WWV (V gamma, Z) in e(+)e(-) collisions at LEP2
- 2010
-
In: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 66:1-2, s. 35-56
-
Journal article (peer-reviewed)abstract
- The data taken by DELPHI at centre-of-mass energies between 189 and 209 GeV are used to place limits on the CP-conserving trilinear gauge boson couplings Delta g(1)(Z), lambda(gamma) and Delta k(gamma) associated to W+W- and single W production at LEP2. Using data from the jjl nu, jjjj, jjX and lX final states, where j,l and X represent a jet, a lepton and missing four-momentum, respectively, the following limits are set on the couplings when one parameter is allowed to vary and the others are set to their Standard Model values of zero: Delta g(1)(Z) =-0.025-(+0.033)(0.030,), lambda(gamma) = 0.002(-0.035)(+0.035) and Delta k(gamma) = 0.024(-0.081)(+0.077). Results are also presented when two or three parameters are allowed to vary. All observations are consistent with the predictions of the Standard Model and supersede the previous results on these gauge coupling parameters published by DELPHI.
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| 30. |
- Abdallah, J, et al.
(author)
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Search for eta(b) in two-photon collisions at LEP II with the DELPHI detector
- 2006
-
In: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 634:4, s. 340-346
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Journal article (peer-reviewed)abstract
- The pseudoscalar meson eta(b) has been searched for in two-photon interactions at LEP II. The data sample corresponds to a total integrated luminosity of 617 pb(-1) at centre-of-mass energies ranging from 161 to 209 GeV. Upper limits at a confidence level of 95% on the product Gamma(gamma gamma) (eta(b)) x BR(eta(b)) are 190, 470 and 660 eV/c(2) for the eta(b) decaying into 4, 6 and 8 charged particles, respectively.
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| 31. |
- Abdallah, J., et al.
(author)
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Search for excited leptons in e(+)e(-) collisions at root s=189-209 GeV
- 2006
-
In: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 46:2, s. 277-293
-
Journal article (peer-reviewed)abstract
- A search for excited lepton production in e(+)e(-) collisions was performed using the data collected by the DELPHI detector at LEP at centre-of-mass energies ranging from 189 GeV to 209 GeV, corresponding to an integrated luminosity of approximately 600 pb(-1). No evidence for excited lepton production was found. In searches for pair-produced excited leptons, lower mass limits were established in the range 94-103 GeV/c(2), depending on the channel and model assumptions. In searches for singly-produced excited leptons, upper limits on the parameter f/Lambda were established as a function of the mass.
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| 32. |
- Abdallah, J., et al.
(author)
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Search for one large extra dimension with the DELPHI detector at LEP
- 2009
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In: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 60:1, s. 17-23
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Journal article (peer-reviewed)abstract
- Single photons detected by the DELPHI experiment at LEP2 in the years 1997-2000 are reanalysed to investigate the existence of a single extra dimension in a modified ADD scenario with slightly warped large extra dimensions. The data collected at centre-of-mass energies between 180 and 209 GeV for an integrated luminosity of similar to 650 pb(-1) agree with the predictions of the Standard Model and allow a limit to be set on graviton emission in one large extra dimension. The limit obtained on the fundamental mass scale M-D is 1.69 TeV/c(2) at 95% CL, with an expected limit of 1.71 TeV/c(2).
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| 33. |
- Abdallah, J., et al.
(author)
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Search for pentaquarks in the hadronic decays of the Z boson with the DELPHI detector at LEP
- 2007
-
In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 653:2-4, s. 151-160
-
Journal article (peer-reviewed)abstract
- The quark model does not exclude states composed of more than three quarks, like pentaquark systems. Controversial evidence for such states has been published in the last years, in particular: for a strange pentaquark Theta(1540)(+); for a double-strange state, the Xi(1862)(--), subsequently called Phi(1860)--; and for a charmed state, the Theta(c)(3100)(0). If confirmed, a full pentaquark family might exist; such pentaquark states could be produced in e(+)e(-) annihilations near the Z energy. In this Letter a search for pentaquarks is described using the DELPHI detector at LEP, characterized by powerful particle identification sub-systems crucial in the separation of the signal from the background for these states. At 95% CL, upper limits are set on the production rates N of such particles and their charge-conjugate state per Z decay: N-Theta+ x Br(Theta(+) -> pK(S)(0)) < 5.1 x 10(-4), N Theta++ < 1.6 x 10(-3), N Phi(1860)-- x Br((P(1860)-- -> Xi(-)pi(-)) < 2.9 x 10(-4), N-Theta c(3100)0 x Br(Theta(c)(3100)(0) -> D*(+)p) < 8.8 x 10(-4).
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| 34. |
- Abdallah, J., et al.
(author)
-
Search for single top quark production via contact interactions at LEP2
- 2011
-
In: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 71:2, s. 1555-
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Journal article (peer-reviewed)abstract
- Single top quark production via four-fermion contact interactions associated to flavour-changing neutral currents was searched for in data taken by the DELPHI detector at LEP2. The data were accumulated at centre-of-mass energies ranging from 189 to 209 GeV, with an integrated luminosity of 598.1 pb(-1). No evidence for a signal was found. Limits on the energy scale Lambda, were set for scalar-, vector- and tensor-like coupling scenarios.
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| 35. |
- Abdallah, J., et al.
(author)
-
Single intermediate vector boson production in e(+)e(-) collisions at root s=183-209 GeV
- 2006
-
In: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 45:2, s. 273-289
-
Journal article (peer-reviewed)abstract
- The production of single charged and neutral intermediate vector bosons in e(+)e(-) collisions has been studied in the data collected by the DELPHI experiment at LEP at centre-of-mass energies between 183 and 209 GeV, corresponding to an integrated luminosity of about 640 pb(-1). The measured cross-sections for the reactions, determined in limited kinematic regions, are in agreement with the Standard Model predictions.
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| 36. |
- Abdallah, J., et al.
(author)
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Study of the dependence of direct soft photon production on the jet characteristics in hadronic Z (0) decays
- 2010
-
In: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 67:3-4, s. 343-366
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Journal article (peer-reviewed)abstract
- An analysis of the direct soft photon production rate as a function of the parent jet characteristics is presented, based on hadronic events collected by the DELPHI experiment at LEP1. The dependences of the photon rates on the jet kinematic characteristics (momentum, mass, etc.) and on the jet charged, neutral and total hadron multiplicities are reported. Up to a scale factor of about four, which characterizes the overall value of the soft photon excess, a similarity of the observed soft photon behavior to that of the inner hadronic bremsstrahlung predictions is found for the momentum, mass, and jet charged multiplicity dependences. However for the dependence of the soft photon rate on the jet neutral and total hadron multiplicities a prominent difference is found for the observed soft photon signal as compared to the expected bremsstrahlung from final state hadrons. The observed linear increase of the soft photon production rate with the jet total hadron multiplicity and its strong dependence on the jet neutral multiplicity suggest that the rate is proportional to the number of quark pairs produced in the fragmentation process, with the neutral pairs being more effectively radiating than the charged ones.
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| 37. |
- Abdallah, J., et al.
(author)
-
Z gamma* production in e(+) e(-) interactions at root s=183-209 GeV
- 2007
-
In: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 51:3, s. 503-523
-
Journal article (peer-reviewed)abstract
- Measurements of Z gamma* production are presented using data collected by the DELPHI detector at centre-of-mass energies ranging from 183 to 209 GeV, corresponding to an integrated luminosity of about 667 pb(-1). The measurements cover a wide range of the possible final state four-fermion configurations: hadronic and leptonic (e(+) e(-) q (q) over bar, mu(+) mu(-) q (q) over bar ,q (q) over barv (v) over bar), fully leptonic (l(+) l(-) l' (+) l'(-)) and fully hadronic. nal states (q (q) over barq (q) over bar, with a low mass q (q$) over bar pair). Measurements of the Z gamma* cross-section for the various. nal states have been compared with the Standard Model expectations and found to be consistent within the errors. In addition, a total cross-section measurement of the l(+) l(-) l'(+)l'(-) cross-section is reported, and found to be in agreement with the prediction of the Standard Model.
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| 38. |
- Dahlqvist, Per, et al.
(author)
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Effects of postischemic environment on transcription factor and serotonin receptor expression after permanent focal cortical ischemia in rats
- 2003
-
In: Neuroscience. - 1873-7544 .- 0306-4522. ; 119:3, s. 643-652
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Journal article (peer-reviewed)abstract
- Housing rats in an enriched environment improves functional outcome after ischemic stroke, this may reflect neuronal plasticity in brain regions outside the lesion. Which components of the enriched environment that are of greatest importance for recovery after brain ischemia is uncertain. We have previously found that enriched environment and social interaction alone both improve functional recovery after focal cerebral ischemia, compared with isolated housing with voluntary wheel-running. In this study, the aim was to separate components of the enriched environment and investigate the effects on some potential mediators of improved functional recovery; such as the inducible transcription factors nerve growth factor-induced gene A (NGFI-A) and NGFI-B, and the glucocorticoid and serotonin systems. After permanent middle cerebral artery occlusion, rats were divided into four groups: individually housed with no equipment (deprived group), individually housed with free access to a running wheel (running group), housed together in a large cage with no equipment (social group) or in a large cage furnished with exchangeable bars, chains and other objects (enriched group). mRNA expression of inducible transcription factors, serotonin and glucocorticoid receptors was determined with in situ hybridisation 1 month after cerebral ischemia. Rats housed in enriched or social environments showed significantly higher mRNA expression of NGFI-A and NGFI-B in cortical regions outside the lesion and in the CA1 (cornu ammonis region of the hippocampus), compared with isolated rats with or without a running wheel. NGFI-A and NGFI-B mRNA expression in cortex and in CA1 was significantly correlated to functional outcome. 5-Hydroxytryptamine receptor 1A (5-HT1A) mRNA expression and binding, as well as 5-HT2A receptor mRNA expression were decreased in the hippocampus (CA4 region) of the running wheel rats. Mineralocorticoid receptor gene expression was increased in the dentate gyrus amongst wheel-running rats. No group differences were found in plasma corticosterone levels or mRNA levels of glucocorticoid receptor, corticotropin-releasing hormone, 5-HT2C or c-fos. In conclusion, we have found that social interaction is a major component of the enriched environment regarding the effects on NGFI-A and NGFI-B expression. These transcription factors may be important mediators of improved functional recovery after brain infarctions, induced by environmental enrichment. (C) 2003 IBRO. Published by Elsevier Science Ltd. All rights reserved.
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| 39. |
- Dahlqvist, Per, et al.
(author)
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Environmental enrichment alters nerve growth factor-induced gene A and glucocorticoid receptor messenger RNA expression after middle cerebral artery occlusion in rats
- 1999
-
In: Neuroscience. - 1873-7544 .- 0306-4522. ; 93:2, s. 527-535
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Journal article (peer-reviewed)abstract
- Housing rats in an enriched environment after focal brain ischemia improves functional outcome without changes in infarct volume, suggesting neuroplastic changes outside the lesion. In this study, permanent occlusion of the middle cerebral artery was followed by housing in an enriched or a standard environment. Nerve growth factor-induced gene A and glucocorticoid receptor messenger RNA expression were determined by in situ hybridization two to 30 days after middle cerebral artery occlusion. Stroke induced a decrease in nerve growth factor-induced gene A messenger RNA expression in cortical areas outside the ischemic lesion and in the CA1 subregion of the hippocampus two to three days after ischemia. This decrease was more prolonged with environmental enrichment, lasting until 20 days. However, 30 days after focal cerebral ischemia, environmental enrichment increased nerve growth factor-induced gene A expression compared to standard housing. A reduction of hippocampal glucocorticoid receptor (type II) messenger RNA two to 12 days after stroke in standard housed rats was restored by environmental enrichment. These data suggest that improved functional outcome induced by environmental enrichment after middle cerebral artery occlusion is associated with dynamically altered expression of nerve growth factor-induced gene A messenger RNA in brain regions outside the ischemic lesion, and sustained levels of hippocampal glucocorticoid receptor messenger RNA expression.
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| 40. |
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| 41. |
- Johansson, Eva, 1949, et al.
(author)
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Etik i skolans vardag
- 2003
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In: I A. Persson, (Red.) Skolkulturer. - Lund : Studentlitteratur. - 9789144028804 ; , s. 57-70
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Book chapter (other academic/artistic)
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| 42. |
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| 43. |
- Johansson, K, et al.
(author)
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Can sensory stimulation improve the functional outcome in stroke patients?
- 1993
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In: Neurology. - 1526-632X. ; 43:11, s. 2189-2192
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Journal article (peer-reviewed)abstract
- After obtaining informed consent, we randomized 78 patients with severe hemiparesis of the left or right side within 10 days of stroke onset: 40 to a control group receiving daily physiotherapy and occupational therapy, and 38 to a group that, in addition, we treated with sensory stimulation (acupuncture) twice a week for 10 weeks. The median age was 76 years for both groups. Motor function, balance, and ADL (Barthel's Index) were assessed before the start of treatment and at 1 and 3 months after stroke onset; ADL was also assessed after 12 months. We assessed the quality of life (QL) using the Nottingham Health Profile 3, 6, and 12 months after stroke onset. Patients given sensory stimulation recovered faster and to a larger extent than the controls, with a significant difference for balance, mobility, ADL, QL, and days spent at hospitals/nursing homes. Whether acupuncture per se is responsible for the differences requires further study.
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| 44. |
- Magnusson, Måns, et al.
(author)
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Sensory stimulation promotes normalization of postural control after stroke
- 1994
-
In: Stroke: a journal of cerebral circulation. - 1524-4628. ; 25:6, s. 1176-1180
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Journal article (peer-reviewed)abstract
- BACKGROUND AND PURPOSE: In a randomized study of hemiparetic stroke patients with a median age of 75 years, functional recovery was significantly better in those who received additional sensory stimulation (n = 38), including electrostimulation, than in control patients (n = 40) given the same physiotherapy and occupational therapy; group differences for balance, mobility, and activities of daily living were significant. The present study was designed to investigate postural control in patients who survived more than 2 years after stroke onset. METHODS: The 48 survivors (mean, 2.7 years; range, 2.0 to 3.8 years), 22 from the treatment group and 26 from the control group, were compared with 23 age-matched healthy subjects. Subjects were perturbed by vibrators applied to calf muscles or with galvanic vestibular stimulation. We evaluated postural control in terms of sway variances or sway velocities and the dynamics of postural control as a feedback system using system identification with a model previously validated for human postural control. RESULTS: Significantly more patients of the treatment group than of the control group maintained stance during perturbations (P < .01). Among patients capable of maintaining stance during perturbation, the control patients were characterized by significant divergence from normal values in two of the three characteristic parameters of dynamic postural control (ie, swiftness and stiffness; P < .05) compared with the treatment subgroup or age-matched subjects. CONCLUSIONS: The course of sensory stimulation enhanced recovery of postural function, an enhancement still significant 2 years after the lesion and treatment. The differences and near normalization of characteristic parameters of dynamic postural control among treated patients suggest that improved recovery after sensory stimulation may be achieved by patients regaining normal or near normal dynamics of human postural control.
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| 45. |
- Åsman, Barbro, et al.
(author)
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Search for charged Higgs bosons : combined results using LEP data
- 2013
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In: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 73:7
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Journal article (peer-reviewed)abstract
- The four LEP collaborations, ALEPH, DELPHI, L3 and OPAL, have searched for pair-produced charged Higgs bosons in the framework of Two Higgs Doublet Models (2HDMs). The data of the four experiments have been statistically combined. The results are interpreted within the 2HDM for Type I and Type II benchmark scenarios. No statistically significant excess has been observed when compared to the Standard Model background prediction, and the combined LEP data exclude large regions of the model parameter space. Charged Higgs bosons with mass below 80 GeV/c(2) (Type II scenario) or 72.5 GeV/c(2) (Type I scenario, for pseudo-scalar masses above 12 GeV/c(2)) are excluded at the 95 % confidence level.
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| 46. |
- Aad, G., et al.
(author)
-
- 2014
-
In: The European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6052. ; 74:8
-
Journal article (peer-reviewed)
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| 47. |
- Aad, G., et al.
(author)
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- 2012
-
Journal article (peer-reviewed)
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| 48. |
- Aad, G., et al.
(author)
-
- 2012
-
Journal article (peer-reviewed)
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| 49. |
- Aad, G., et al.
(author)
-
- 2012
-
Journal article (peer-reviewed)
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| 50. |
- Aad, G., et al.
(author)
-
- 2013
-
Journal article (peer-reviewed)
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