60,748 research outputs found

    Parton-shower Effects in Vector-Boson-Fusion Processes

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    We investigate the effects of combining next-to-leading order QCD results with parton-shower effects in W+WjjW^+W^-jj production via vector-boson fusion including leptonic decays. Using the Herwig 7 framework interfaced to VBFNLO 3, we compare the predictions obtained from the angular-ordered and dipole-based parton shower algorithms combined with subtractive, MC@NLO-type, and multiplicative, Powheg-type, matching. A consistent treatment of renormalisation and factorisation scale variations in the hard process and the parton shower allows to assign more reliable theory uncertainty predictions to key distributions like the central rapidity gap.Comment: 5 pages, 3 figures, to appear in the proceedings of DIS201

    Utilization of space resources in the space transportation system

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    Utilization of space resources (i.e., raw materials obtained from nonterrestrial sources) has often been cited as a prerequisite for large-scale industrialization and habitation of space. While transportation of extremely large quantities of material from Earth would be costly and potentially destructive to our environment, vast quantities of usable resources might be derived from the Moon, the asteroids, and other celestial objects in a cost-effective and environmentally benign manner. The primary purpose of the parametric cost model developed as part of this study is to identify the factors that have the greatest influence on the economics of space resource utilization. In the near term, this information can be used to devise strategies for technology development so that capabilities developed will produce cost-effective results

    Coagulation and anticoagulation in idiopathic pulmonary fibrosis

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    Idiopathic pulmonary fibrosis (IPF) is an incurable, progressive interstitial lung disease with a prognosis that is worse than that of many cancers. Epidemiological studies have demonstrated a link between IPF and thrombotic vascular events. Coagulation and fibrinolytic systems play central roles in wound healing and repair, processes hypothesised to be abnormal within the IPF lung. Animal models of pulmonary fibrosis have demonstrated an imbalance between thrombosis and fibrinolysis within the alveolar compartment, a finding that is also observed in IPF patients. A systemic prothrombotic state also occurs in IPF and is associated with increased mortality, but trials of anticoagulation in IPF have provided conflicting results. Differences in methodology, intervention and study populations may contribute to the inconsistent trial outcomes. The new oral anticoagulants have properties that may prove advantageous in targeting both thrombotic risk and progression of lung fibrosis

    Configuration Path Integral Monte Carlo Approach to the Static Density Response of the Warm Dense Electron Gas

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    Precise knowledge of the static density response function (SDRF) of the uniform electron gas (UEG) serves as key input for numerous applications, most importantly for density functional theory beyond generalized gradient approximations. Here we extend the configuration path integral Monte Carlo (CPIMC) formalism that was previously applied to the spatially uniform electron gas to the case of an inhomogeneous electron gas by adding a spatially periodic external potential. This procedure has recently been successfully used in permutation blocking path integral Monte Carlo simulations (PB-PIMC) of the warm dense electron gas [Dornheim \textit{et al.}, Phys. Rev. E in press, arXiv:1706.00315], but this method is restricted to low and moderate densities. Implementing this procedure into CPIMC allows us to obtain exact finite temperature results for the SDRF of the electron gas at \textit{high to moderate densities} closing the gap left open by the PB-PIMC data. In this paper we demonstrate how the CPIMC formalism can be efficiently extended to the spatially inhomogeneous electron gas and present the first data points. Finally, we discuss finite size errors involved in the quantum Monte Carlo results for the SDRF in detail and present a solution how to remove them that is based on a generalization of ground state techniques

    (Biphenyl-2-yl)bromidobis(2-methyltetrahydrofuran-[kappa]O)magnesium(II)

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    In the title Grignard reagent, [MgBr(C12H9)(C5H10O)2], the Mg centre adopts a distorted tetrahedral MgCO2Br arrangement. The dihedral angle between the two aromatic rings of the biphenyl residue is 44.00 (14)°. Each molecule incorporates one R- and one S-configured 2-methyltetrahydrofuran molecule. Key indicators: single-crystal X-ray study; T = 173 K; mean σ(C–C) = 0.007 Å; R factor = 0.045; wR factor = 0.108; data-to-parameter ratio = 17.4

    Singlet-doublet fermion and triplet scalar dark matter with radiative neutrino masses

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    We present a detailed study of a combined singlet-doublet fermion and triplet scalar model for dark matter. These models have only been studied separately in the past. Together, they form a simple extension of the Standard Model that can account for dark matter and explain the existence of neutrino masses, which are generated radiatively. This holds even if singlet-doublet fermions and triplet scalars never contribute simultaneously to the dark matter abundance. However, this also implies the existence of lepton flavour violating processes. In addition, this particular model allows for gauge coupling unification. The new fields are odd under a new Z2\mathbb{Z}_2 symmetry to stabilise the dark matter candidate. We analyse the dark matter, neutrino mass and lepton flavour violation aspects both separately and in conjunction, exploring the viable parameter space of the model. This is done using a numerical random scan imposing successively the neutrino mass and mixing, relic density, Higgs mass, direct detection, collider and lepton flavour violation constraints. We find that dark matter in this model is fermionic for masses below about 1 TeV and scalar above. The narrow mass regions found previously for the two separate models are enlarged by their coupling. While coannihilations of the weak isospin partners are sizeable, this is not the case for fermions and scalars despite their often similar masses due to the relatively small coupling of the two sectors, imposed by the small neutrino masses. We observe a high degree of complementarity between direct detection and lepton flavour violation experiments, which should soon allow to fully probe the fermionic dark matter sector and at least partially the scalar dark matter sector.Comment: 24 pages, 12 figures; version accepted by and published in JHE

    Singlet-doublet/triplet dark matter and neutrino masses

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    In these proceedings, we present a study of a combined singlet--doublet fermion and triplet scalar model for dark matter (DM). Together, these models form a simple extension of the Standard Model (SM) that can account for DM and explain the existence of neutrino masses, which are generated radiatively. However, this also implies the existence of lepton flavour violating (LFV) processes. In addition, this particular model allows for gauge coupling unification. The new fields are odd under a new Z2\mathbb{Z}_2 symmetry to stabilise the DM candidate. We analyse the DM, neutrino mass and LFV aspects, exploring the viable parameter space of the model. This is done using a numerical random scan imposing successively the neutrino mass and mixing, relic density, Higgs mass, direct detection, collider and LFV constraints. We find that DM in this model is fermionic for masses below about 1 TeV and scalar above. We observe a high degree of complementarity between direct detection and LFV experiments, which should soon allow to fully probe the fermionic DM sector and at least partially the scalar DM sector.Comment: 4 pages, 1 figure; contribution to the 2019 EW session of the 54th Rencontres de Moriond (summary of arXiv:1812.11133
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