706 research outputs found
Leading-twist light cone distribution amplitudes for p-wave heavy quarkonium states
In this paper, a study of light-cone distribution amplitudes for p-wave heavy
quarkonium states are presented. Within the light-front framework, the leading
twist light-cone distribution amplitudes, and their relevant decay constants,
have some simple relations. These relations can be further simplified when the
non-relativistic limit and the wave function as a function of relative momentum
|\vec\kappa| are taken into consideration. In addition, the \kappa_\perp
integrations in the equations of LCDAs and \xi-moments can be completed
analytically when the Gaussian-type wave function is considered. After fixing
the parameters that appear in the wave function, the curves and the
corresponding decay constants of the LCDAs are plotted and calculated for the
charmonium and bottomonium states. The first three \xi-moments of the LCDAs are
estimated and are consistent with those of other theoretical approaches.Comment: 25 pages, 2 figures, some details and one reference added; version to
appear in JHE
Measurements of the optical mirror coating properties
The results of measurement of optical mirror coating are presented. These
results indicate that Standard Quantum Limit of sensitivity can be reached in
the second stage of LIGO project if it is limited by thermoelastic noise in the
coating only.Comment: 5 page
Design optimisation for cold rolled steel beam sections with complex stiffeners considering cold working effects
This paper presents the analysis and design optimization of the cold rolled steel sections for flexural strength considering the effect of cold working exerted on the section during the roll forming process. The sections included channel and zed shapes with complex longitudinal web and flange stiffeners. Nonlinear Finite Element (FE) modelling was developed to model the flexural strength of the channel and zed beams and validated against the four-point bending experiments for these sections. The material properties of steel at the section’s flat parts, corners, and stiffener bends were obtained from tensile tests and were incorporated into the FE simulations to account for the true material properties at these regions. The section strength was then optimized using FE modelling results based on the Design of Experiments (DOE) and response surface methodology. Optimal designs for the channel and zed sections with maximum strength in distortional buckling could be obtained while changing the stiffeners’ position, shape, sizes, and considering material properties at section corners and stiffener bends. It revealed that, the optimal designs provided up to 13% and 17% increase in flexural strength for the channel and zed sections, respectively; however, when the true material properties at the section corner and the stiffener’s bend regions was included, the increase in flexural strength increased up to 20% and 23%, respectively
1864-05-31 Martin V.B. Judkins wishes to go to Augusta for his discharge
https://digitalmaine.com/cw_me_3rd_regiment_corr/1556/thumbnail.jp
Thermodynamical fluctuations in optical mirror coatings
Thermodynamical fluctuations of temperature in mirrors may produce surface
fluctuations not only through thermal expansion in mirror body but also through
thermal expansion in mirror coating. We analyze the last "surface" effect which
can be larger than the first "volume" one due to larger thermal expansion
coefficient of coating material and smaller effective volume. In particular,
these fluctuations may be important in laser interferometric gravitational
antennae.Comment: 12 pages, LaTex, 3 figure
Effect of disorder on superconductivity in the boson-fermion model
We study how a randomness of either boson or fermion site energies affects
the superconducting phase of the boson fermion model. We find that, contrary to
what is expected for s-wave superconductors, the non-magnetic disorder is
detrimental to the s-wave superconductivity. However, depending in which
subsystem the disorder is located, we can observe different channels being
affected. Weak disorder of the fermion subsystem is responsible mainly for
renormalization of the single particle density of states while disorder in the
boson subsystem directly leads to fluctuation of the strength of the effective
pairing between fermions.Comment: 7 pages, 6 figures. Physical Review B (accepted for publication
Velocity-force characteristics of a driven interface in a disordered medium
Using a dynamic functional renormalization group treatment of driven elastic
interfaces in a disordered medium, we investigate several aspects of the
creep-type motion induced by external forces below the depinning threshold
: i) We show that in the experimentally important regime of forces
slightly below the velocity obeys an Arrhenius-type law
with an effective energy barrier
vanishing linearly when f approaches the threshold . ii) Thermal
fluctuations soften the pinning landscape at high temperatures. Determining the
corresponding velocity-force characteristics at low driving forces for internal
dimensions d=1,2 (strings and interfaces) we find a particular non-Arrhenius
type creep involving the reduced threshold
force alone. For d=3 we obtain a similar v-f characteristic which is,
however, non-universal and depends explicitly on the microscopic cutoff.Comment: 9 pages, RevTeX, 3 postscript figure
Determination of the high-twist contribution to the structure function
We extract the high-twist contribution to the neutrino-nucleon structure
function from the analysis of the data collected by
the IHEP-JINR Neutrino Detector in the runs with the focused neutrino beams at
the IHEP 70 GeV proton synchrotron. The analysis is performed within the
infrared renormalon (IRR) model of high twists in order to extract the
normalization parameter of the model. From the NLO QCD fit to our data we
obtained the value of the IRR model normalization parameter
. We
also obtained from a similar fit to the CCFR data. The average of both results is
.Comment: preprint IHEP-01-18, 7 pages, LATEX, 1 figure (EPS
Synchronization of multi-phase oscillators: An Axelrod-inspired model
Inspired by Axelrod's model of culture dissemination, we introduce and
analyze a model for a population of coupled oscillators where different levels
of synchronization can be assimilated to different degrees of cultural
organization. The state of each oscillator is represented by a set of phases,
and the interaction --which occurs between homologous phases-- is weighted by a
decreasing function of the distance between individual states. Both ordered
arrays and random networks are considered. We find that the transition between
synchronization and incoherent behaviour is mediated by a clustering regime
with rich organizational structure, where some of the phases of a given
oscillator can be synchronized to a certain cluster, while its other phases are
synchronized to different clusters.Comment: 6 pages, 5 figure
Unified time analysis of photon and (nonrelativistic) particle Tunnelling, and the Superluminal group-velocity problem
A unified approach to the time analysis of tunnelling of nonrelativistic
particles is presented, in which Time is regarded as a quantum-mechanical
observable, canonically conjugated to Energy. The validity of the Hartman
effect (independence of the Tunnelling Time of the opaque barrier width, with
Superluminal group velocities as a consequence) is verified for ALL the known
expressions of the mean tunnelling time. Moreover, the analogy between particle
and photon tunnelling is suitably exploited. On the basis of such an analogy,
an explanation of some recent microwave and optics experimental results on
tunnelling times is proposed. Attention is devoted to some aspects of the
causality problem for particle and photon tunnelling.Comment: plain (old) LaTeX; 42 pages; plus figures 1, 2, 3, 4a, 4b, and
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