235 research outputs found
Probing the braneworld hypothesis with a neutron-shining-through-a-wall experiment
The possibility for our visible world to be a 3-brane embedded in a
multidimensional bulk is at the heart of many theoretical edifices in
high-energy physics. Probing the braneworld hypothesis is thus a major
experimental challenge. Following recent theoretical works showing that matter
swapping between braneworlds can occur, we propose a
neutron-shining-through-a-wall experiment. We first show that an intense
neutron source such as a nuclear reactor core can induce a hidden neutron flux
in an adjacent hidden braneworld. We then describe how a low-background
detector can detect neutrons arising from the hidden world and quantify the
expected sensitivity to the swapping probability. As a proof of concept, a
constraint is derived from previous experiments.Comment: 12 pages, 4 figures, final version published in Physical Review
Search for passing-through-walls neutrons constrains hidden braneworlds
In many theoretical frameworks our visible world is a -brane, embedded in
a multidimensional bulk, possibly coexisting with hidden braneworlds. Some
works have also shown that matter swapping between braneworlds can occur. Here
we report the results of an experiment - at the Institut Laue-Langevin
(Grenoble, France) - designed to detect thermal neutron swapping to and from
another braneworld, thus constraining the probability of such an event.
The limit, at C.L., is orders of magnitude
better than the previous bound based on the disappearance of stored ultracold
neutrons. In the simplest braneworld scenario, for two parallel Planck-scale
branes separated by a distance , we conclude that in Planck length
units.Comment: 5 pages, 3 figures. Published in Physics Letters
Trigger and readout electronics for the STEREO experiment
The STEREO experiment will search for a sterile neutrino by measuring the
anti-neutrino energy spectrum as a function of the distance from the source,
the ILL nuclear reactor. A dedicated electronic system, hosted in a single
microTCA crate, was designed for this experiment. It performs triggering in two
stages with various selectable conditions, processing and readout via UDP/IPBUS
of 68 photomultiplier signals continuously digitized at 250 MSPS. Additionally,
for detector performance monitoring, the electronics allow on-line calibration
by driving LED synchronously with the data acquisition. This paper describes
the electronics requirements, architecture and the performances achieved.Comment: Topical Workshop on Electronics for Particle Physics (TWEPP) 2015,
Lisboa. 9 pages, 9 figure
Sub MeV Particles Detection and Identification in the MUNU detector ((1)ISN, IN2P3/CNRS-UJF, Grenoble, France, (2)Institut de Physique, Neuch\^atel, Switzerland, (3) INFN, Padova Italy, (4) Physik-Institut, Z\"{u}rich, Switzerland)
We report on the performance of a 1 m TPC filled with CF at 3
bar, immersed in liquid scintillator and viewed by photomultipliers. Particle
detection, event identification and localization achieved by measuring both the
current signal and the scintillation light are presented. Particular features
of particle detection are also discussed. Finally, the Mn
photopeak, reconstructed from the Compton scattering and recoil angle is shown.Comment: Latex, 19 pages, 20 figure
Highlighting type A RRs as potential regulators of the dkHK1 multi-step phosphorelay pathway in Populus
In previous studies, we highlighted a multistep phosphorelay (MSP) system in poplars composed of two hybrid-type Histidine aspartate Kinases, dkHK1a and dkHK1b, which interact with three Histidine Phosphotransfer proteins, dkHPt2, 7, and 9, which in turn interact with six type B Response Regulators. These interactions correspond to the dkHK1a-b/dkHPts/dkRRBs MSP. This MSP is putatively involved in an osmosensing pathway, as dkHK1a-b are orthologous to the Arabidopsis osmosensor AHK1, and able to complement a mutant yeast deleted for its osmosensors. Since type A RRs have been characterized as negative regulators in cytokinin MSP signaling due to their interaction with HPt proteins, we decided in this study to characterize poplar type A RRs and their implication in the MSP. For a global view of this MSP, we isolated 10 poplar type A RR cDNAs, and determined their subcellular localization to check the in silico prediction experimentally. For most of them, the in planta subcellular localization was as predicted, except for three RRAs, for which this experimental approach gave a more precise localization. Interaction studies using yeast two-hybrid and in planta BiFC assays, together with transcript expression analysis in poplar organs led to eight dkRRAs being singled out as partners which could interfere the dkHK1a-b/dkHPts/dkRRBs MSP identified in previous studies. Consequently, the results obtained in this study now provide an exhaustive view of dkHK1a-b partners belonging to a poplar MSP
Cardiac magnetic resonance imaging in systemic sclerosis: a cross-sectional observational study of 52 patients
The TIANSHAN Radio Experiment for Neutrino Detection
An antenna array devoted to the autonomous radio-detection of high energy
cosmic rays is being deployed on the site of the 21 cm array radio telescope in
XinJiang, China. Thanks in particular to the very good electromagnetic
environment of this remote experimental site, self-triggering on extensive air
showers induced by cosmic rays has been achieved with a small scale prototype
of the foreseen antenna array. We give here a detailed description of the
detector and present the first detection of extensive air showers with this
prototype.Comment: 37 pages, 15 figures. Astroparticle Physics (in press
Improvement of the photocatalytic degradation property of atomic layer deposited ZnO thin films: the interplay between film properties and functional performances:
In this work, we have evidenced the impact of stoichiometry on the photocatalytic properties of ZnO nanofilms grown by atomic layer deposition (ALD). We point out the importance of hydrogen incorporation and propose here a model explaining the presence of Zn-OH impurities in the form of a ZnOxHy amorphous matrix hosting ZnO crystallites. We evidence that this phase prevails in films grown at low temperatures and prevents the photoluminescence and photocatalytic activity of ZnO films. We also point out that high temperature ALD processes promote the preferential growth of ZnO films in the (002) orientation, leading to a significant increase of the film wettability and so their photocatalytic degradation performances
Comment on "On the subtleties of searching for dark matter with liquid xenon detectors"
In a recent manuscript (arXiv:1208.5046) Peter Sorensen claims that
XENON100's upper limits on spin-independent WIMP-nucleon cross sections for
WIMP masses below 10 GeV "may be understated by one order of magnitude or
more". Having performed a similar, though more detailed analysis prior to the
submission of our new result (arXiv:1207.5988), we do not confirm these
findings. We point out the rationale for not considering the described effect
in our final analysis and list several potential problems with his study.Comment: 3 pages, no figure
On the operation of a Micropattern Gaseous UV-Photomultiplier in Liquid-Xenon
Operation results are presented of a UV-sensitive gaseous photomultiplier
(GPM) coupled through a MgF2 window to a liquid-xenon scintillator. It
consisted of a reflective CsI photocathode deposited on top of a THick Gaseous
Electron Multiplier (THGEM); further multiplication stages were either a second
THGEM or a Parallel Ionization Multiplier (PIM) followed by a MICROMEsh GAseous
Structure (MICROMEGAS). The GPM operated in gas-flow mode with non-condensable
gas mixtures. Gains of 10^4 were measured with a CsI-coated double-THGEM
detector in Ne/CH4 (95:5), Ne/CF4 (95:5) and Ne/CH4/CF4 (90:5:5), with soft
X-rays at 173 K. Scintillation signals induced by alpha particles in liquid
xenon were measured here for the first time with a double-THGEM GPM in He/CH4
(92.5:7.5) and a triple-structure THGEM/PIM/MICROMEGAS GPM in Ne/CH4 (90:10)
with a fast-current preamplifier.Comment: 12 pages, 9 figures, submitted to JINS
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