51,054 research outputs found
Theoretical description of the , and reactions
We have made a study of the (with
being and ) and assuming
the axial vector mesons to be dynamically generated from the
pseudoscalar-vector meson interaction. We have taken the needed input from
previous studies of the reactions.
We obtain fair agreement with experimental data and provide an explanation on
why the recent experiment on observed in the mode observes the peak of the
at a higher energy than its nominal mass.Comment: 21 pages, 6 figure
Flavor symmetry breaking effects on SU(3) Skyrmion
We study the massive SU(3) Skyrmion model to investigate the flavor symmetry
breaking (FSB) effects on the static properties of the strange baryons in the
framework of the rigid rotator quantization scheme combined with the improved
Dirac quantization one. Both the chiral symmetry breaking pion mass and FSB
kinetic terms are shown to improve the ratio of the strange-light to
light-light interaction strengths and that of the strange-strange to
light-light.Comment: 12 pages, latex, no figure
Detailed Geant4 simulations of the ANITA and ANITA-CUP neutron facilities
Simulations of the ANITA spallation neutron source at The Svedberg Laboratory (TSL) are described. Neutron radiation calculations show close agreement with measurements at both standard and close user positions. Gamma radiation characteristics are also predicted
New spectral classification technique for X-ray sources: quantile analysis
We present a new technique called "quantile analysis" to classify spectral
properties of X-ray sources with limited statistics. The quantile analysis is
superior to the conventional approaches such as X-ray hardness ratio or X-ray
color analysis to study relatively faint sources or to investigate a certain
phase or state of a source in detail, where poor statistics does not allow
spectral fitting using a model. Instead of working with predetermined energy
bands, we determine the energy values that divide the detected photons into
predetermined fractions of the total counts such as median (50%), tercile (33%
& 67%), and quartile (25% & 75%). We use these quantiles as an indicator of the
X-ray hardness or color of the source. We show that the median is an improved
substitute for the conventional X-ray hardness ratio. The median and other
quantiles form a phase space, similar to the conventional X-ray color-color
diagrams. The quantile-based phase space is more evenly sensitive over various
spectral shapes than the conventional color-color diagrams, and it is naturally
arranged to properly represent the statistical similarity of various spectral
shapes. We demonstrate the new technique in the 0.3-8 keV energy range using
Chandra ACIS-S detector response function and a typical aperture photometry
involving background subtraction. The technique can be applied in any energy
band, provided the energy distribution of photons can be obtained.Comment: 11 pages, 9 figures, accepted for publication in Ap
Spin Chain with Magnetic Field and Spinning String in Magnetic Field Background
We analyze the fast-moving string in the magnetic Melvin field background and
find that the associated effective Lagrangian of string sigma model describes
the spin chain model with external magnetic field. The spin vector in the spin
chain has been properly deformed and is living on the deformed two-sphere or
deformed two-dimensional hyperboloid, depending on the direction around which
the string is spinning. We describe in detail the characters of spin
deformation and, in particular, see that this is a general property for a
string moving in a class of deformed background.Comment: Latex 10 pages, add a figure and a section, change titl
A comparative study of benchmarking approaches for non-domestic buildings: Part 1 – Top-down approach
Benchmarking plays an important role in improving energy efficiency of non-domestic buildings. A review of energy benchmarks that underpin the UK’s Display Energy Certificate (DEC) scheme have prompted necessities to explore the benefits and limitations of using various methods to derive energy benchmarks. The existing methods were reviewed and grouped into top-down and bottom-up approaches based on the granularity of the data used. In the study, two top-down methods, descriptive statistics and artificial neural networks (ANN), were explored for the purpose of benchmarking energy performances of schools. The results were used to understand the benefits of using these benchmarks for assessing energy efficiency of buildings and the limitations that affect the robustness of the derived benchmarks. Compared to the bottom-up approach, top-down approaches were found to be beneficial in gaining insight into how peers perform. The relative rather than absolute feedback on energy efficiency meant that peer pressure was a motivator for improvement. On the other hand, there were limitations with regard to the extent to which the energy efficiency of a building could be accurately assessed using the top-down benchmarks. Moreover, difficulties in acquiring adequate data were identified as a key limitation to using the top-down approach for benchmarking non-domestic buildings. The study suggested that there are benefits in rolling out of DECs to private sector buildings and that there is a need to explore more complex methods to provide more accurate indication of energy efficiency in non-domestic buildings
Spinning String and Giant Graviton in Electric/Magnetic Field Deformed
We apply the transformation of mixing azimuthal and internal coordinate or
mixing time and internal coordinate to the 11D M-theory with a stack of
M2-branes M2-branes, then, through the mechanism of Kaluza-Klein
reduction and a series of the T duality we obtain the corresponding background
of a stack of D1-branes D5-branes which, in the near-horizon limit,
becomes the magnetic or electric Melvin field deformed . We find the giant graviton solution in the deformed spacetime and see
that the configuration whose angular momentum is within a finite region could
has a fixed size and become more stable than the point-like graviton, in
contrast to the undeformed giant graviton which only exists when its angular
momentum is a specific value and could have arbitrary size. We discuss in
detail the properties of how the electric/magnetic Melvin field will affect the
size of the giant gravitons. We also adopt an ansatz to find the classical
string solutions which are rotating in the deformed with an angular
momentum in the rotation plane. The spinning string and giant graviton
solutions we obtained show that the external magnetic/electric flux will
increase the solution energy. Therefore, from the AdS/CFT point of view, the
corrections of the anomalous dimensions of operators in the dual field theory
will be positive. Finally, we also see that the spinning string and giant
graviton in the near-horizon spacetime of Melvin field deformed D5-branes
background have the similar properties as those in the deformed .Comment: Latex 21 pages, slightly detail calculation
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