The ANTARES deep sea neutrino telescope has been continuously taking data for more than ten years. Thanks to its excellent angular resolution in both the muon channel and the cascade channel, ANTARES ...offers unprecedented sensitivity for neutrino source searches in the Southern sky in the TeV-PeV energy range, so that already valuable constraints have been set on the origin of the cosmic neutrino flux discovered by the IceCube detector. This document highlights recent results obtained by ANTARES in the search for high energy cosmic neutrinos coming from point or extended sources, from multi-messenger analyses of transient sources, and from indirect searches for Dark Matter.
Among the different strategies aiming to detect WIMP dark matter (DM), a neutrino signal coming from the Sun would be a smoking gun. This possibility relies on the DM capture by the Sun driven by the ...local DM distribution assumptions: the local mass density and the velocity distribution. In this context, we revisit those astrophysical hypotheses (also relevant for direct detection). We focus especially on the DM velocity distribution considering different possibilities beyond the popular Maxwellian distribution. Namely, some alternatives can be considered through analytical approaches and by looking into cosmological simulations of spiral galaxies. Most of the fitting formulas used to constrain the local velocity distribution function fail to describe the peak and the high velocity tail of the velocity distribution observed in simulations, the latter being improved when adding the local escape velocity of DM into the benchmark fitting models. In addition we test the predictions by the Eddington inversion method and also illustrate the importance of the galactic dynamical history. We estimate the resulting uncertainties on the DM capture rate by the Sun and conclude that different velocity distributions will affect the capture rate of DM by the Sun up to a 15–20%. On top of that, the calculation of the intrinsic variance of the capture rate leads to poorly controlled uncertainties especially for high WIMP masses (>30 GeV) raising concerns about the capture scenario.
The flux of very high-energy neutrinos produced in our Galaxy by the interaction of accelerated cosmic rays with the interstellar medium is not yet determined. The characterization of this flux will ...shed light on Galactic accelerator features, gas distribution morphology and Galactic cosmic ray transport. The central Galactic plane can be the site of an enhanced neutrino production, thus leading to anisotropies in the extraterrestrial neutrino signal as measured by the IceCube Collaboration. The ANTARES neutrino telescope, located in the Mediterranean Sea, offers a favorable view of this part of the sky, thereby allowing for a contribution to the determination of this flux. The expected diffuse Galactic neutrino emission can be obtained, linking a model of generation and propagation of cosmic rays with the morphology of the gas distribution in the Milky Way. In this paper, the so-called “gamma model” introduced recently to explain the high-energy gamma-ray diffuse Galactic emission is assumed as reference. The neutrino flux predicted by the “gamma model” depends on the assumed primary cosmic ray spectrum cutoff. Considering a radially dependent diffusion coefficient, this proposed scenario is able to account for the local cosmic ray measurements, as well as for the Galactic gamma-ray observations. Nine years of ANTARES data are used in this work to search for a possible Galactic contribution according to this scenario. All flavor neutrino interactions are considered. No excess of events is observed, and an upper limit is set on the neutrino flux of 1.1 (1.2) times the prediction of the “gamma model,” assuming the primary cosmic ray spectrum cutoff at 5 (50) PeV. This limit excludes the diffuse Galactic neutrino emission as the major cause of the “spectral anomaly” between the two hemispheres measured by IceCube.
Indirect search for Dark Matter trapped inside celestial bodies is one of the main physics goals of neutrino telescopes. The expected sensitivity of ANTARES with its data recorded in 2007 and 2008 to ...detect the flux of neutrinos originating from Dark Matter annihilations inside the Sun is presented. A comparison to current limits coming from direct detection experiments and other indirect detection experiments is shown with regards to the predictions of popular models such as the CMSSM and the Minimal Universal Dimension model.
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TiO2 and Sn-doped TiO2 materials were prepared by sol–gel method using titanium and tin alkoxides at different Sn concentration (0.1mol%, 0.5mol%, 1mol%, 3mol% and 5mol%). Samples ...were characterized by thermo gravimetric analyzer with differential scanning calorimeter (TGA–DSC), X-ray Rietveld refinement, N2 adsorption (BET), transmission electron microscopy (TEM), UV–vis spectroscopies technology and Raman spectroscopy. Only anatase phase was observed in pure TiO2, whereas anatase and brookite were obtained in Sn-doped TiO2 samples. Sn dopant acts as a promoter in phase transformation of TiO2. The Rietveld refinements method was used to determine the relative weight of anatase and brookite, and crystallite size as a function of Sn concentration after calcination of samples at 673K. It was also demonstrated the incorporation of Sn4+ into the anatase TiO2 structure. Sn4+ inhibits the growth of TiO2 crystallite size, which leads to an increase of the specific surface area of TiO2. From XRD analysis, the solid solution limit of Sn4+ into TiO2 is 5mol% Sn. The photocatalytic activity on Sn4+ doped TiO2 was determined for the 2,4-dichlorophenoxyacetic acid reaction. The maximum in activity was attributed to the coexistence of anatase and brookite phases in the appropriate ratio and crystallite size.
Driving simulators are increasingly being used for driver evaluation and/or education. In this paper, we describe the design and the modeling aspects of a 2-degree-of-freedom (2-DOF) low-cost motion ...platform allowing the rendering of the longitudinal and yaw movements. This prototype will be used to study various configurations of motion rendering and the impact of these variants on controllability and simulator sickness. The whole motion platform is considered as two coupled systems that are linked mechanically. The first system consists of a motorized rail for the longitudinal movement, which is mounted on top of the second system, which is a motorized turret allowing rotation of the platform. We present the platform mechanics and a number of experimental studies that have been carried out to obtain a characterization of the platform capabilities and frequency responses, as well as to assess platform performance in a classical drive operation. First conclusions and directions of future work are presented.
Indirect search for Dark Matter trapped inside celestial bodies is one of the main physics goals of neutrino telescopes. The expected flux coming from supersymmetric Dark Matter annihilations in the ...Sun and the sensitivity of the ANTARES and KM3NeT detectors to such a signal are presented. The ANTARES detector has been taking data during its construction phase in 2007 with five lines operational. This allowed to set a first limit on the neutrino flux coming from Dark Matter annihilations in the Sun with this experiment. A limit on Dark Matter to proton cross section in the framework of Minimal Universal Extra Dimension model is also presented.
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•Reduction of the nitrous oxide (N2O) toxic molecule by neutral Rh6 clusters.•Density functional theory calculations including ZORA relativistic effects.•Dissociation of N2O by Rh6 as ...catalyst, without support or dopping substances.•Active sites of the Rh6+N2O reaction pathways, in different multiplicities.•Rh6 is one of the smallest particles with many active sites, able to reduce N2O.
The interaction of Rh6 clusters with the nitrous oxide (N2O) molecule was studied by means of density functional theory (DFT) calculations through the zero-order-regular approximation (ZORA), which includes relativistic effects explicitly. The purpose of this work is to characterize the N2O reduction to N2 and O by Rh6 clusters. The identified low-lying and degenerate states of Rh6, octahedron with multiplicities of 1 and 7, and a triangular prism with a septet, present many active sites of reduction. The initial steps of the N2O+Rh6 reaction were studied through different adsorption modes, each one having different multiplicities. The RhRh bonds define the active sites to produce N2O dissociation. The most successful reaction pathway originates when the linear NNO molecule is approached parallel to the RhRh bonds, being this active site the most numerous in the systems. The NO bond breaks in five addressed multiplicities, with 2 and 3 degenerate energy cases in the octahedron. Other approaches studied are: N2O pointing toward the triangular or square face bisectors or to the surface between two RhRh bonds. In these two cases, the N2O molecule moves toward one of the RhRh bonds dissociating over it. Overall, to reduce N2O, the prism structure presents a greater number of different active sites, but the octahedron has more edges, in which the oxide can break. For each calculation, many parameters were obtained and are included in the text: vibrational frequencies, distances between atoms, binding energies, total electronic charges, as well as optimized geometries. An important result of this work is the feature that Rh6 is the smallest nanoparticle having several structures at the ground state, which greatly increases the number of active sites being able to reduce the nitrous oxide contaminant.
A
bstract
A search for magnetic monopoles using five years of data recorded with the ANTARES neutrino telescope from January 2008 to December 2012 with a total live time of 1121 days is presented. ...The analysis is carried out in the range
β
> 0.6 of magnetic monopole velocities using a strategy based on run-by-run Monte Carlo simulations. No signal above the background expectation from atmospheric muons and atmospheric neutrinos is observed, and upper limits are set on the magnetic monopole flux ranging from 5.7 × 10
−16
to 1.5 × 10
−18
cm
−2
·s
−1
·sr
−1
.
•Rhn+N2O reaction study must consider the geometry of the reactants and spin.•N2O reduction mechanism catalysed by Rhn clusters ends up breaking the N2O bond.•The N2O activation never occurs through ...the NN bond rupture.•Most of Rh clusters capture N2O and there are some spin states that also activate it.•The spin states transfer enough charge from Rh to N2O to break the N2O bond.
This work presents many possible theoretical reaction pathways of N2O reduction to N2 and O on Rhn nanoparticles (n=1–4) using density functional theory (DFT) method and the zero order regular approximation (ZORA), which explicitly considers the scalar relativistic corrections. The Rh spin multiplicity is an essential condition to dissociate N2O, because can promote or inhibit the electron back donation from the metal. Rh activates N2O by exothermic and spontaneous reactions. For each case presented, the optimized geometry adsorption site, reaction energy, spin multiplicity and Voronoi charges are calculated. On a single Rh atom in the ground and low-lying excited states, the N2O is captured only. On the Rh2 quintet ground state, N2O is also chemisorbed and dissociation occurs for the next two excited states (triplet and septet). In the Rh3 case, there are N2O adsorption and dissociation for Rh3 quartet ground state and for most excited states. Several dissociation cases take place when N2O is parallel to the plane and parallel to a Rh3 bond. On the Rh4, however, there are two optimal geometries: tetrahedral and square; for both cases there are N2O adsorption and dissociation.
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