6,488 research outputs found
New Signatures of Squarks
When the gluino is light and long lived, missing energy is a poor signature
for both squarks and gluinos. Instead, production in and
collisions characteristically results in events with jets.
Methods are proposed for deciding whether an observed excess of 4-jet events is
due to production. The recent report by ALEPH of observation of 14
4-jet events when 7 were expected is discussed.Comment: 12/22/95 version (put on net 1/1/96) elaborates remarks on squarks as
possible source of ALEPH 4-jet excess and adds a ref. latex, 10 pages
(including 1 figure), uufile
Dark Matter and the Baryon Asymmetry
We present a mechanism to generate the baryon asymmetry of the Universe which
preserves the net baryon number created in the Big Bang. If dark matter
particles carry baryon number , and , the 's freeze out at a higher temperature
and have a larger relic density than 's. If m_X \lsi 4.5 B_X GeV and the
annihilation cross sections differ by (10%) or more, this type of
scenario naturally explains the observed . Two
concrete examples are given, one of which can be excluded on observational
grounds
Scattering from a Domain Wall in a Spontaneously Broken Gauge Theory
We study the interaction of particles with a domain wall at a
symmetry-breaking phase transition by perturbing about the domain wall
solution. We find the particulate excitations appropriate near the domain wall
and relate them to the particles present far from the wall in the uniform
broken and unbroken phases. For a quartic Higgs potential we find analytic
solutions to the equations of motion and derive reflection and transmission
coefficients. We discover several bound states for particles near the wall.
Finally, we apply our results to the electroweak phase transition in the
standard model.Comment: 48 pages, 10 figures, LaTeX / epsf, revised to include references to
earlier related wor
Mock Catalogs for UHECR Studies
We provide realistic mock-catalogs of cosmic rays above 40 EeV, for a pure
proton composition, assuming their sources are a random subset of ordinary
galaxies in a simulated, volume-limited survey, for various choices of source
density: 10^-3.5 Mpc^-3, 10^-4.0 Mpc^-3 and 10^-4.5 Mpc^-3. The spectrum at the
source is taken to be E^-2.3 and the effects of cosmological redshifting as
well as photo-pion and e^+ e^- energy losses are included.Comment: 7 pages, 4 figure
Damage and repair classification in reinforced concrete beams using frequency domain data
This research aims at developing a new vibration-based damage classification technique that can efficiently be applied to a real-time large data. Statistical pattern recognition paradigm is relevant to perform a reliable site-location damage diagnosis system. By adopting such paradigm, the finite element and other inverse models with their intensive computations, corrections and inherent inaccuracies can be avoided. In this research, a two-stage combination between principal component analysis and Karhunen-Loéve transformation (also known as canonical correlation analysis) was proposed as a statistical-based damage classification technique. Vibration measurements from frequency domain were tested as possible damage-sensitive features. The performance of the proposed system was tested and verified on real vibration measurements collected from five laboratory-scale reinforced concrete beams modelled with various ranges of defects. The results of the system helped in distinguishing between normal and damaged patterns in structural vibration data. Most importantly, the system further dissected reasonably each main damage group into subgroups according to their severity of damage. Its efficiency was conclusively proved on data from both frequency response functions and response-only functions. The outcomes of this two-stage system showed a realistic detection and classification and outperform results from the principal component analysis-only. The success of this classification model is substantially tenable because the observed clusters come from well-controlled and known state conditions
Using voice to tag digital photographs on the spot
Tagging of media, particularly digital photographs, has become a very popular and efficient means of organizing material on the internet and on personal computers. Tagging, though, is normally accomplished long after the images have been captured, possibly at the expense of in-the-moment information. Although some digital cameras have begun to automatically populate the various fields of a photograph\u27s metadata, these generic labels often lack in the descriptiveness presented through user-observed annotations and therefore stress the necessity of a user-driven input method. However, most mobile annotation applications demand a great number of keystrokes in order for users to tag photographs and thereby focus the user\u27s attention inward. Specifically, the problem is that these applications require users to take their eyes off the environment while typing in tags. We hypothesize that we can shift the user\u27s focus away from the mobile device and back to their environment by creating a mobile annotation application which accepts voice commands. In other words, our major hypothesis is that a convenient way of tagging digital photographs is by using voice commands
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