Search results for "construct"
showing 10 items of 3723 documents
ALICE: Physics performance report, volume II
2006
ALICE is a general-purpose heavy-ion experiment designed to study the physics of strongly interacting matter and the quark-gluon plasma in nucleus-nucleus collisions at the LHC. It currently involves more than 900 physicists and senior engineers, from both the nuclear and high-energy physics sectors, from over 90 institutions in about 30 countries. The ALICE detector is designed to cope with the highest particle multiplicities above those anticipated for Pb-Pb collisions (dN(ch)/dy up to 8000) and it will be operational at the start-up of the LHC. In addition to heavy systems, the ALICE Collaboration will study collisions of lower-mass ions, which are a means of varying the energy density, …
Search for the DecayB+→K+νν¯
2005
We search for the rare flavor-changing neutral-current decay ${B}^{+}\ensuremath{\rightarrow}{K}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}}$ in a data sample of $82\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ collected with the BABAR detector at the PEP-II $B$-factory. Signal events are selected by examining the properties of the system recoiling against either a reconstructed hadronic or semileptonic charged-$B$ decay. Using these two independent samples we obtain a combined limit of $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{K}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}})l5.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ at the 90% confidence level. In addition, by…
The EUSO Data Simulation and Analysis Tree
2004
The "Extreme Universe Space Observatory - EUSO" is the first Space mission devoted to the exploration of the outermost bounds of the Universe through the investigation of the Extremely-High Energy Cosmic Rays, EECR, using the Earth atmosphere as a giant detector. The objective is to obtain a detailed description of the Cosmic Ray spectrum beyond 5×1019 eV together with a map of the arrival directions. EUSO will detect EECR looking at the streak of fluorescence light produced when such a particle interacts with the atmosphere. The signal will be detected after its propagation upward from the dark Earth atmosphere to the EUSO telescope accommodated, as external payload, on the International S…
Fractional Tajimi–Kanai model for simulating earthquake ground motion
2014
The ground acceleration is usually modeled as a filtered Gaussian process. The most common model is a Tajimi–Kanai (TK) filter that is a viscoelastic Kelvin–Voigt unit (a spring in parallel with a dashpot) carrying a mass excited by a white noise (acceleration at the bedrock). Based upon the observation that every real material exhibits a power law trend in the creep test, in this paper it is proposed the substitution of the purely viscous element in the Kelvin Voigt element with the so called springpot that is an element having an intermediate behavior between purely elastic (spring) and purely viscous (dashpot) behavior ruled by fractional operator. With this choice two main goals are rea…
The Ultra Fast Flash Observatory pathfinder – UFFO-p GRB imaging and location with its coded mask X-ray imager UBAT
2013
The UFFO pathfinder mission will attempt to locate the optical afterglow of a GRB within seconds of its detection and location by a wide field X-ray imager. It will be mounted on the Lomonosov spacecraft for launch in 2013 and consists of a coded mask X-ray imager UBAT to detect a GRB and estimate a direction vector which will be passed to the SMT optical system which will rotate a moveable mirror to lock onto the GRB and direct the optical afterglow to a camera with a ~17′ wide aperture. We present the design geometry of the UBAT instrument only, with results of simulations for a range of GRB types to show probable photon integration times to be expected to extract a significant FOV image…
A Pixelated Silicon Positron Sensitive Imaging Probe
2006
A pixelated silicon positron sensitive imaging probe is under development to precisely localize superficially located tumors accumulating 18F-FDG. 18F-FDG has been a radioisotope of interest mainly because of the high uptake in tumors and the relatively short positron range. Silicon detectors have generally low detection efficiency for high energy photons and can be used for positron detection. We present a pixelated silicon positron sensitive imaging probe that has the 1.4-by-1.4-by-1.0 mm pixel size with equivalent electronic noise of ~1.2 keV FWHM. The small pixel size leads to the high spatial resolution. Probe movement in conjunction with appropriate reconstruction will allow sub-pixel…
Resurgent Deformation Quantisation
2013
We construct a version of the complex Heisenberg algebra based on the idea of endless analytic continuation. In particular, we exhibit an integral formula for the product of resurgent operators with algebraic singularities. This algebra would be large enough to capture quantum effects that escape ordinary formal deformation quantisation.
Non-perturbative QCD effective charges
2009
Using gluon and ghost propagators obtained from Schwinger-Dyson equations (SDEs), we construct the non-perturbative effective charge of QCD. We employ two different definitions, which, despite their distinct field-theoretic origin, give rise to qualitative comparable results, by virtue of a crucial non-perturbative identity. Most importantly, the QCD charge obtained with either definition freezes in the deep infrared, in agreement with theoretical and phenomenological expectations. The various theoretical ingredients necessary for this construction are reviewed in detail, and some conceptual subtleties are briefly discussed.
Measurements of integrated direct, diffuse and global ultraviolet-B radiation
2015
Abstract We present the first multiyear set of simultaneous measurements of the global ultraviolet-B radiation and its two components: direct and diffuse. The measurements have been taken with four YES-UVB-1 radiometers: two radiometers to measure the diffuse radiation, one provided with a shadow band and the other with a shadow disk on a Sun tracker; a radiometer to measure the global horizontal radiation; and a Sun-tracking radiometer to measure the direct radiation with an especially designed radiance collimator. The diffuse minute-values measured with both instruments agree within a coefficient correlation of 1.00. The diffuse component represents at least 50% of the global UVB (ultravi…
Constructive role of non-adiabaticity for quantized charge pumping
2010
We investigate a recently developed scheme for quantized charge pumping based on single-parameter modulation. The device was realized in an AlGaAl-GaAs gated nanowire. It has been shown theoretically that non-adiabaticity is fundamentally required to realize single-parameter pumping, while in previous multi-parameter pumping schemes it caused unwanted and less controllable currents. In this paper we demonstrate experimentally the constructive and destructive role of non-adiabaticity by analysing the pumping current over a broad frequency range.