19,567,583 research outputs found
The Elusive p-air Cross Section
For the \pbar p and systems, we have used all of the extensive data of
the Particle Data Group[K. Hagiwara {\em et al.} (Particle Data Group), Phys.
Rev. D 66, 010001 (2002).]. We then subject these data to a screening process,
the ``Sieve'' algorithm[M. M. Block, physics/0506010.], in order to eliminate
``outliers'' that can skew a fit. With the ``Sieve'' algorithm, a
robust fit using a Lorentzian distribution is first made to all of the data to
sieve out abnormally high \delchi, the individual i point's
contribution to the total . The fits are then made to the
sieved data. We demonstrate that we cleanly discriminate between asymptotic
and behavior of total hadronic cross sections when we require
that these amplitudes {\em also} describe, on average, low energy data
dominated by resonances. We simultaneously fit real analytic amplitudes to the
``sieved'' high energy measurements of and total cross sections
and -values for GeV, while requiring that their asymptotic
fits smoothly join the the and total cross
sections at 4.0 GeV--again {\em both} in magnitude and slope. Our
results strongly favor a high energy fit, basically excluding a fit. Finally, we make a screened Glauber fit for the p-air cross section,
using as input our precisely-determined cross sections at cosmic ray
energies.Comment: 15 pages, 6 figures, 2 table,Paper delivered at c2cr2005 Conference,
Prague, September 7-13, 2005. Fig. 2 was missing from V1. V3 fixes all
figure
Supersymmetric CP-violating Currents and Electroweak Baryogenesis
In this work we compute the CP-violating currents of the right-handed stops
and Higgsinos, induced by the presence of non-trivial vacuum expectation values
of the Higgs fields within the context of the minimal supersymmetric extension
of the Standard Model (MSSM) with explicit CP-violating phases. Using the
Keldysh formalism, we perform the computation of the currents at finite
temperature, in an expansion of derivatives of the Higgs fields. Contrary to
previous works, we implement a resummation of the Higgs mass insertion effects
to all orders in perturbation theory. While the components of the right-handed
stop current j^\mu_{\widetilde t_R} become proportional to the difference H_2
\partial^{\mu}H_1-H_1 \partial^{\mu} H_2 (suppressed by \Delta\beta), the
Higgsino currents, j^\mu_{\widetilde{H}_i}, present contributions proportional
to both H_2 \partial^{\mu}H_1\pm H_1 \partial^{\mu} H_2. For large values of
the charged Higgs mass and moderate values of \tan\beta the contribution to the
source proportional to H_2 \partial^{\mu}H_1+H_1 \partial^{\mu} H_2 in the
diffusion equations become sizeable, although it is suppressed by the Higgsino
number violating interaction rate \Gamma_\mu^{-1/2}. For small values of the
wall velocity, 0.04\simlt v_\omega \simlt 0.1, the total contribution leads to
acceptable values of the baryon asymmetry for values of the CP-violating phases
\phi_{CP} in the range 0.04\simlt|\sin\phi_{CP}|\simlt 1. Finally, we comment
on the relevance of the latest results of Higgs searches at LEP2 for the
mechanism of electroweak baryogenesis within the MSSM.Comment: 27 pages, 4 figures, latex2e. Typo corrected and references adde
Effect of a Pipe Number on the Heat Transfer Rate for a Granit Stone Absorber Solar Collector
As the fossil energy has been getting depletion, it is important to utilize alternative energies such as solar energy. An equipment that can be used for capturing and converting solar energy is solar collector. Two identical collectors used in this study were placed facing to the North with an inclination angle of 15°. The collector dimension was 0.8 m x 1 m x 0.05 m. One collector contained 5 parallel pipes and the other contained 7 parallel pipes. The water used in the test was flowed naturally due to the gravity force from a higher tank and was adjusted using a valve fitted at the end of the collector. The water flow rates employed were 200, 250 and 300 cc/minutes and measured using a volume meter and a stop watch. The results showed that the energy coming into the collector, energy absorbed by the absorber and water, increased with an increase in the observation time and reached the peak value at about 2.30 pm. After that, they decreased. The effect of the pipe number is significant and the performance of the collector containing 7 pipes is better than that containing 5 pipes
Laboratory glassware rack for seismic safety
A rack for laboratory bottles and jars for chemicals and medicines has been designed to provide the maximum strength and security to the glassware in the event of a significant earthquake. The rack preferably is rectangular and may be made of a variety of chemically resistant materials including polypropylene, polycarbonate, and stainless steel. It comprises a first plurality of parallel vertical walls, and a second plurality of parallel vertical walls, perpendicular to the first. These intersecting vertical walls comprise a self-supporting structure without a bottom which sits on four legs. The top surface of the rack is formed by the top edges of all the vertical walls, which are not parallel but are skewed in three dimensions. These top edges form a grid matrix having a number of intersections of the vertical walls which define a number of rectangular compartments having varying widths and lengths and varying heights
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