| 1. |
- Aad, G., et al.
(författare)
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- 2014
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Aad, G., et al.
(författare)
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- 2014
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Aad, G., et al.
(författare)
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- 2014
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Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; :11
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Tidskriftsartikel (refereegranskat)
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| 4. |
- Aad, G., et al.
(författare)
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- 2014
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Tidskriftsartikel (refereegranskat)
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| 5. |
- Aad, G., et al.
(författare)
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- 2014
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Tidskriftsartikel (refereegranskat)
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| 6. |
- Aad, G., et al.
(författare)
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- 2014
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Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; :11
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Tidskriftsartikel (refereegranskat)
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| 7. |
- Aad, G., et al.
(författare)
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- 2014
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Tidskriftsartikel (refereegranskat)
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| 8. |
- Schael, S., et al.
(författare)
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Electroweak measurements in electron positron collisions at W-boson-pair energies at LEP
- 2013
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 532:4, s. 119-244
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Forskningsöversikt (refereegranskat)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. |
- Barkley, Michael P., et al.
(författare)
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Can a "state of the art" chemistry transport model simulate Amazonian tropospheric chemistry?
- 2011
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Ingår i: Journal of Geophysical Research. - 2156-2202. ; 116, s. 16302-16302
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Tidskriftsartikel (refereegranskat)abstract
- We present an evaluation of a nested high-resolution Goddard Earth Observing System (GEOS)-Chem chemistry transport model simulation of tropospheric chemistry over tropical South America. The model has been constrained with two isoprene emission inventories: (1) the canopy-scale Model of Emissions of Gases and Aerosols from Nature (MEGAN) and (2) a leaf-scale algorithm coupled to the Lund-Potsdam-Jena General Ecosystem Simulator (LPJ-GUESS) dynamic vegetation model, and the model has been run using two different chemical mechanisms that contain alternative treatments of isoprene photo-oxidation. Large differences of up to 100 Tg C yr (1) exist between the isoprene emissions predicted by each inventory, with MEGAN emissions generally higher. Based on our simulations we estimate that tropical South America (30-85 degrees W, 14 degrees N-25 degrees S) contributes about 15-35% of total global isoprene emissions. We have quantified the model sensitivity to changes in isoprene emissions, chemistry, boundary layer mixing, and soil NOx emissions using ground-based and airborne observations. We find GEOS-Chem has difficulty reproducing several observed chemical species; typically hydroxyl concentrations are underestimated, whilst mixing ratios of isoprene and its oxidation products are overestimated. The magnitude of model formaldehyde (HCHO) columns are most sensitive to the choice of chemical mechanism and isoprene emission inventory. We find GEOS-Chem exhibits a significant positive bias (10-100%) when compared with HCHO columns from the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) and Ozone Monitoring Instrument (OMI) for the study year 2006. Simulations that use the more detailed chemical mechanism and/or lowest isoprene emissions provide the best agreement to the satellite data, since they result in lower-HCHO columns.
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| 10. |
- Kalvius, G. M., et al.
(författare)
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Magnetism of Pd1-xNix alloys near the critical concentration for ferromagnetism
- 2014
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 89:6, s. 064418-
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Tidskriftsartikel (refereegranskat)abstract
- We report results of a muon spin rotation and relaxation (mu SR) study of dilute Pd1-xNix alloys, with emphasis on Ni concentrations x = 0.0243 and 0.025. These are close to the critical value x(cr) for the onset of ferromagnetic long-range order (LRO), which is a candidate for a quantum critical point. Additional control data were taken for pure nonmagnetic Pd, and for an alloy where ferromagnetism is well established (x = 0.05). The 2.43 and 2.5 at.% Ni alloys exhibit similar mu SR properties. Both samples are fully magnetic, with average zero-temperature muon local fields < B-loc(T = 0)> = 2.0 and 3.8 mT and Curie temperatures T-C = 1.0 and 2.03 K for 2.43 and 2.5 at.% Ni, respectively. The temperature dependence of < B-loc > suggests ordering of Ni spin clusters rather than isolated spins. Just above T-C, the temperature where LRO vanishes, a two-phase region is found with coexisting separate volume fractions of quasistatic short-range order (SRO) and paramagnetism. The SRO fraction decreases to zero with increasing temperature a few kelvin above T-C. This mixture of SRO and paramagnetism is consistent with the notion of an inhomogeneous alloy with Ni clustering. The measured values of T-C extrapolate to x(cr) = 0.0236 +/- 0.0027. The dynamic muon spin relaxation in the vicinity of T-C differs for the two samples: a relaxation-rate maximum at T-C is observed for x = 0.0243, reminiscent of critical slowing down, whereas for x = 0.025 no dynamic relaxation is observed within the mu SR time window. The data suggest a mean-field-like transition in this alloy.
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