60,748 research outputs found
Parton-shower Effects in Vector-Boson-Fusion Processes
We investigate the effects of combining next-to-leading order QCD results
with parton-shower effects in 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
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
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
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)
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
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 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
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 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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