Search results for "530"

CONTRIBUTION OF PSEUDO-FOCUSED SOFT PROTONS TO THE BACKGROUND OF ATHENA

2021

This PhD thesis explores the role of low energy protons, the so-called ‘soft protons', as a component of the background in view of the future ESA's X-ray mission Athena. As a matter of fact, a high level of soft proton flux at the focal plane of Athena can adversely affect the scientific goals of the mission. To prevent this, a correct estimate of the soft proton flux expected at the focal plane of the satellite is fundamental. Such an estimate can be achieved only if the reflectivity of soft protons from the optics is well understood, with efforts on both the experimental and the theoretical sides. To this aim, I applied the model of reflectivity of particles at grazing incidence proposed …

Propagation Length of Antiferromagnetic Magnons Governed by Domain Configurations.

2019

Spintronics seeks to functionalize antiferromagnetic materials to develop memory and logic devices operating at terahertz speed and robust against external magnetic field perturbations. To be useful, such functionality needs to be developed in thin film devices. The key functionality of long-distance spin-transport has, however, so far only been reported in bulk single crystal antiferromagnets, while in thin films, transport has so far been limited to a few nanometers. In this work, we electrically achieve a long-distance propagation of spin-information in thin films of the insulating antiferromagnet hematite. Through transport and magnetic imaging, we demonstrate a strong correlation betwe…

Impact of buffer gas quenching on the $^1S_0$ $\to$ $^1P_1$ ground-state atomic transition in nobelium

2017

International audience; Using the sensitive Radiation Detected Resonance Ionization Spectroscopy (RADRIS) techniquean optical transition in neutral nobelium (No, Z = 102) was identified. A remnant signal when delaying the ionizing laser indicated the influence of a strong buffer gas induced de-excitation of the optically populated level. A subsequent investigation of the chemical homologue, ytterbium (Yb, Z = 70), enabled a detailed study of the atomic levels involved in this process, leading to the development of a rate equation model. This paves the way for characterizing resonance ionization spectroscopy (RIS) schemes used in the studyof nobelium and beyond, where atomic properties are c…

Electron and photon energy calibration with the ATLAS detector using 2015-2016 LHC proton-proton collision data

2019

Artículo realizado por muchos autores. Solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración y los autores que firman como pertenecientes a la UAM

GW170814: A Three-Detector Observation of Gravitational Waves from a Binary Black Hole Coalescence

2017

On August 14, 2017 at 10 30:43 UTC, the Advanced Virgo detector and the two Advanced LIGO detectors coherently observed a transient gravitational-wave signal produced by the coalescence of two stellar mass black holes, with a false-alarm rate of 1 in 27 000 years. The signal was observed with a three-detector network matched-filter signal-to-noise ratio of 18. The inferred masses of the initial black holes are 30.5-3.0+5.7M and 25.3-4.2+2.8M (at the 90% credible level). The luminosity distance of the source is 540-210+130 Mpc, corresponding to a redshift of z=0.11-0.04+0.03. A network of three detectors improves the sky localization of the source, reducing the area of the 90% credible regio…

Surface resistance to heat and mass transfer in a silicalite membrane. A Non-Equilibrium Molecular Dynamics study.

2007

Limits on a muon flux from Kaluza-Klein dark matter annihilations in the Sun from the IceCube 22-string detector

2010

A search for muon neutrinos from Kaluza-Klein dark matter annihilations in the Sun has been performed with the 22-string configuration of the IceCube neutrino detector using data collected in 104.3 days of live-time in 2007. No excess over the expected atmospheric background has been observed. Upper limits have been obtained on the annihilation rate of captured lightest Kaluza-Klein particle (LKP) WIMPs in the Sun and converted to limits on the LKP-proton cross-sections for LKP masses in the range 250 -- 3000 GeV. These results are the most stringent limits to date on LKP annihilation in the Sun.

Charge radius of the short-lived $^{68}$Ni and correlation with the dipole polarizability

2020

We present the first laser spectroscopic measurement of the neutron-rich nucleus $^{68}$Ni at the \mbox{$N=40$} subshell closure and extract its nuclear charge radius. Since this is the only short-lived isotope for which the dipole polarizability $\alpha_{\rm D}$ has been measured, the combination of these observables provides a benchmark for nuclear structure theory. We compare them to novel coupled-cluster calculations based on different chiral two- and three-nucleon interactions, for which a strong correlation between the charge radius and dipole polarizability is observed, similar to the stable nucleus $^{48}$Ca. Three-particle--three-hole correlations in coupled-cluster theory substant…

Generic nature of long-range repulsion mechanism on a bulk insulator?

2017

Dynamic atomic force microscopy measurements are reported that provide evidence for the presence of long-range repulsion in molecular self-assembly on a bulk insulator surface. We present the structures formed from four different benzoic acid derivatives on the (10.4) cleavage plane of calcite kept in ultra-high vacuum. These molecules have in common that they self-assemble into molecular stripes when deposited onto the surface held at room temperature. For all molecules tested, a detailed analysis of the stripe-to-stripe distance distribution reveals a clear deviation from what would be expected for randomly placed, non-interacting stripes (i.e., geometric distribution). When excluding kin…

N-loop running should be combined with N-loop matching

2018

We investigate the high-scale behaviour of Higgs sectors beyond the Standard Model, pointing out that the proper matching of the quartic couplings before applying the renormalisation group equations (RGEs) is of crucial importance for reliable predictions at larger energy scales. In particular, the common practice of leading-order parameters in the RGE evolution is insufficient to make precise statements on a given model's UV behaviour, typically resulting in uncertainties of many orders of magnitude. We argue that, before applying N-loop RGEs, a matching should even be performed at N-loop order in contrast to common lore. We show both analytical and numerical results where the impact is si…