| 1. |
- Erni, W., et al.
(författare)
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Technical design report for the PANDA (AntiProton Annihilations at Darmstadt) Straw Tube Tracker
- 2013
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 49:2
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Tidskriftsartikel (refereegranskat)abstract
- This document describes the technical layout and the expected performance of the Straw Tube Tracker (STT), the main tracking detector of the PANDA target spectrometer. The STT encloses a Micro-Vertex-Detector (MVD) for the inner tracking and is followed in beam direction by a set of GEM stations. The tasks of the STT are the measurement of the particle momentum from the reconstructed trajectory and the measurement of the specific energy loss for a particle identification. Dedicated simulations with full analysis studies of certain proton-antiproton reactions, identified as being benchmark tests for the whole PANDA scientific program, have been performed to test the STT layout and performance. The results are presented, and the time lines to construct the STT are described.
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| 2. |
- Aaron, F. D., et al.
(författare)
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Combined inclusive diffractive cross sections measured with forward proton spectrometers in deep inelastic ep scattering at HERA
- 2012
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 72:10
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Tidskriftsartikel (refereegranskat)abstract
- A combination of the inclusive diffractive cross section measurements made by the H1 and ZEUS Collaborations at HERA is presented. The analysis uses samples of diffractive deep inelastic ep scattering data at a centre-of-mass energy root s = 318 GeV where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertainties are taken into account, resulting in an improved precision of the cross section measurement which reaches 6 % for the most precise points. The combined data cover the range 2.5 < Q(2) < 200 GeV2 in photon virtuality, 0.00035 < x(P) < 0.09 in proton fractional momentum loss, 0.09 < vertical bar t vertical bar < 0.55 GeV2 in squared four-momentum transfer at the proton vertex and 0.0018 < beta < 0.816 in beta = x/x(P), where x is the Bjorken scaling variable.
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| 3. |
- Abramowicz, H., et al.
(författare)
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Combination and QCD analysis of charm production cross section measurements in deep-inelastic ep scattering at HERA
- 2013
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 73:2
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of open charm production cross sections in deep-inelastic ep scattering at HERA from the H1 and ZEUS Collaborations are combined. Reduced cross sections sigma(c (c) over bar)(red) for charm production are obtained in the kinematic range of photon virtuality 2.5 <= Q(2) <= 2000 GeV2 and Bjorken scaling variable 3 . 10(-5) <= x <= 5 . 10(-2). The combination method accounts for the correlations of the systematic uncertainties among the different data sets. The combined charm data together with the combined inclusive deep-inelastic scattering cross sections from HERA are used as input for a detailed NLO QCD analysis to study the influence of different heavy flavour schemes on the parton distribution functions. The optimal values of the charm mass as a parameter in these different schemes are obtained. The implications on the NLO predictions for W-+/- and Z production cross sections at the LHC are investigated. Using the fixed flavour number scheme, the running mass of the charm quark is determined.
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| 4. |
- Murphy, Nicholas P., et al.
(författare)
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Trapped in desert springs : phylogeography of Australian desert spring snails
- 2012
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Ingår i: Journal of Biogeography. - : Wiley. - 0305-0270 .- 1365-2699. ; 39:9, s. 1573-1582
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Tidskriftsartikel (refereegranskat)abstract
- AimWe investigate the phylogeographical history and determine the time-scaleof population divergence of hydrobiid freshwater snails (genus Trochidrobia)inhabiting groundwater springs in the Australian desert. We test the hypothesisthat divergence between geographically distinct snail populations occurredsimultaneously due to their isolation in hydrologically discrete spring systems, i.e.‘trapped in desert springs’.LocationGroundwater springs of the Great Artesian Basin (GAB) in centralAustralia.MethodsDNA sequence data from the mitochondrial cytochrome c oxidasesubunit I gene and the nuclear 28S and internal transcribed spacer rRNA geneswere used to reconstruct phylogenetic relationships within and among threespecies of Trochidrobia (Hydrobiidae): T. punicea (13 spring groups, n = 90),T. smithi (12 spring groups, n = 62) and T. minuta (2 spring groups, n = 4). Bayesian relaxed molecular clock analyses and approximate Bayesian computation were used to date lineage divergence and distinguish betweenalternative biogeographical scenarios.ResultsThe diversification of the three Trochidrobia species probably occurredbetween 2.54 and 9.3 Ma, prior to the formation of the springs c. 1 Ma.Intraspecific divergences within the two widespread species occurred after theformation and colonization of the springs. Coalescent modelling and molecularclock analyses supported a simultaneous radiation of five allopatric intraspecificsnail lineages within T. punicea (two lineages) and T. smithi (three lineages)across the GAB springs examined.Main conclusionsThe analyses support the ‘trapped in desert springs’hypothesis for the diversification of intraspecific lineages within the species T.punicea and T. smithi. This hypothesis suggests that the formation of desertsaround Lake Eyre in the early Pleistocene led to the hydrological isolation ofspring complexes in the GAB, resulting in significant molecular divergence, butno morphological divergence, of Trochidrobia snail populations.
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