19,955 research outputs found
Anomalous Chiral Action from the Path-Integral
By generalizing the Fujikawa approach, we show in the path-integral
formalism: (1) how the infinitesimal variation of the fermion measure can be
integrated to obtain the full anomalous chiral action; (2) how the action
derived in this way can be identified as the Chern-Simons term in five
dimensions, if the anomaly is consistent; (3) how the regularization can be
carried out, so as to lead to the consistent anomaly and not to the covariant
anomaly. Our method uses Schwinger's ``proper-time'' representation of the
Green's function and the gauge invariant point-splitting technique. We find
that the consistency requirement and the point-splitting technique allow both
an anomalous and a non-anomalous action. In the end, the nature of the vacuum
determines whether we have an anomalous theory, or, a non-anomalous theoryComment: 28 page
High Energy pp Elastic Scattering in Condensate Enclosed Chiral Bag Model and TOTEM Elastic Measurements at LHC at 7 TeV
We study high energy and elastic
scattering in the TeV region based on an effective field theory model of the
proton. We phenomenologically investigate the main processes underlying elastic
scattering and quantitatively describe the measured elastic
d/dt at energies 7.0 TeV (LHC ), 1.96 TeV
(Tevatron ), and 0.630 TeV (SPS ). Finally, we give our prediction for elastic
d/dt at 14 TeV that will be measured by the TOTEM
Collaboration.Comment: Presented at EDS Blois 2013 (arXiv:1309.5705
Novel nonalloyed thermally stable Pd/Sn and Pd/Sn/Au ohmic contacts for the fabrication of GaAs MESFETs
GaAs metal-semiconductor field-effect transistors (MESFETs) have been fabricated utilizing thermally stable Pd/Sn and Pd/Sn/Au ohmic contacts for the first time. MESFETs with Pd/Ge ohmic contacts are fabricated for comparison. The thermal stability of the Pd/Sn, Pd/Ge and Pd/Sn/Au ohmic contacts is also presente
pp Elastic Scattering at LHC in a Nucleon-Structure Model
We predict pp elastic differential cross sections at LHC at c.m. energy 14
TeV and momentum transfer range |t| = 0 - 10 GeV*2 in a nucleon-structure
model. In this model, the nucleon has an outer cloud of quark-antiquark
condensed ground state, an inner shell of topological baryonic charge (r ~
0.44F) probed by the vector meson omega, and a central quark-bag (r ~ 0.2F)
containing valence quarks. We also predict elastic differential cross section
in the Coulomb-hadronic interference region. Large |t| elastic scattering in
this model arises from valence quark-quark scattering, which is taken to be due
to the hard-pomeron (BFKL pomeron with next to leading order corrections). We
present results of taking into account multiple hard-pomeron exchanges, i.e.
unitarity corrections. Finally, we compare our prediction of pp elastic
differential cross section at LHC with the predictions of various other models.
Precise measurement of pp elastic differential cross section at LHC by the
TOTEM group in the |t| region 0 - 5 GeV*2 will be able to distinguish between
these models.Comment: To be published in the Proceedings of the 12th International
Conference on Elastic and Diffractive Scattering, DESY, Hamburg. Presented by
M. M. Islam, May 200
An overview on the application of FRP composites in piling system
Traditional pile materials such as steel, concrete and timber have limited service life when used in harsh marine environment. Problems coupled with these piles include deterioration of wood, corrosion of steel and degradation of reinforced concrete. To offset this problem, a relatively new trend in deep foundation industry is to use a fibre reinforced polymer (FRP) composite materials as a substitute in piling system. The fundamental advantages of FRP composites compared to other pile materials include lightweight, high strength and possess resistance against corrosion. However, composite materials face hurdle because they do not have a long track record of use in civil engineering application particularly in piling system. To partly address this obstacle, this paper presents an overview in testing, design, and practice of composite piles. Importance is given to history, material types and properties, structural behaviour, geotechnical performance, and durability of composite piles
Deep-Elastic pp Scattering at LHC from Low-x Gluons
Deep-elastic pp scattering at c.m. energy 14 TeV at LHC in the momentum
transfer range 4 GeV*2 < |t| < 10 GeV*2 is planned to be measured by the TOTEM
group. We study this process in a model where the deep-elastic scattering is
due to a single hard collision of a valence quark from one proton with a
valence quark from the other proton. The hard collision originates from the
low-x gluon cloud around one valence quark interacting with that of the other.
The low-x gluon cloud can be identified as color glass condensate and has size
~0.3 F. Our prediction is that pp differential cross section in the large |t|
region decreases smoothly as momentum transfer increases. This is in contrast
to the prediction of pp differential cross section with visible oscillations
and smaller cross sections by a large number of other models.Comment: 10 pages, including 4 figure
p p Elastic Scattering at LHC and Nucleon Structure
High energy elastic scattering at the Large Hadron Collider (LHC) at
c.m. energy 14 TeV is predicted using the asymptotic behavior of
and known from dispersion relation calculations and
the measured elastic differential cross section at . The effective field theory model underlying the phenomenological
analysis describes the nucleon as having an outer cloud of quark-antiquark
condensed ground state, an inner core of topological baryonic charge of radius
and a still smaller valence quark-bag of radius . The LHC experiment TOTEM (Total and Elastic Measurement), if carried
out with sufficient precision from to , will be
able to test this structure of the nucleon.Comment: 13 pages, 6 figures, to be published in the Modern Physics Letters
Cylindrically symmetric wormholes
This paper discusses traversable wormholes that differ slightly but
significantly from those of the Morris-Thorne type under the assumption of
cylindrical symmetry. The throat is a piecewise smooth cylindrical surface
resulting in a shape function that is not differentiable at some value. It is
proposed that the regular derivative be replaced by a one-sided derivative at
this value. The resulting wormhole geometry satisfies the weak energy
condition.Comment: Supplied missing figures; 15 pages AMSTe
ARDUINO Tutor: An Intelligent Tutoring System for Training on ARDUINO
This paper aims at helping trainees to overcome the difficulties they face when dealing with Arduino platform by describing the design of a desktop based intelligent tutoring system. The main idea of this system is a systematic introduction into the concept of Arduino platform. The system shows the circuit boards of Arduino that can be purchased at low cost or assembled from freely-available plans; and an open-source development environment and library for writing code to control the board topic of Arduino platform.
The system is adaptive with the traineeâs individual progress. The system functions as a special tutor who deals with trainees according to their levels and skills. Evaluation of the system has been applied on professional and unprofessional trainees in this field and the results were good
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