16,658 research outputs found
Form-factors of the sausage model obtained with bootstrap fusion from sine-Gordon theory
We continue the investigation of massive integrable models by means of the
bootstrap fusion procedure, started in our previous work on O(3) nonlinear
sigma model. Using the analogy with SU(2) Thirring model and the O(3) nonlinear
sigma model we prove a similar relation between sine-Gordon theory and a
one-parameter deformation of the O(3) sigma model, the sausage model. This
allows us to write down a free field representation for the
Zamolodchikov-Faddeev algebra of the sausage model and to construct an integral
representation for the generating functions of form-factors in this theory. We
also clear up the origin of the singularities in the bootstrap construction and
the reason for the problem with the kinematical poles.Comment: 16 pages, revtex; references added, some typos corrected. Accepted
for publication in Physical Review
On the nature of the solar-wind-Mars interaction
Plasma measurements near Mars on the U.S.S.R. Mars-2, -3, and -5 spacecraft are considered. The data are compared with simultaneous magnetic measurements. Strong evidence is obtained in favor of a direct interaction and mass exchange between the solar wind plasma and the gaseous envelope of Mars
Dynamics of diproton formation in the and reactions in the GeV region
Mechanisms for the production of diproton pairs, , in the
reaction are studied at proton beam energies 0.5 -- 2 GeV in
kinematics similar to those of backward elastic scattering. This reaction
provides valuable information on the short-range and interactions
that is complementary to that investigated in the well known and
processes. The reaction is related to the
subprocesses and using two different
one--pion--exchange (OPE) diagrams. Within both these models a reasonable
agreement could be obtained with the data below 1GeV. The similar energy
dependence of the and cross sections and the small
ratio of about 1.5% in the production of to deuteron final states
follow naturally within the OPE models.Comment: 10 pages, 7 figures, Late
Scaling aspects of the sea-ice-drift dynamics and pack fracture
A study of the sea-ice dynamics in the periods of time prior to and during the cycles of basin-wide fragmentation of the ice cover in the Arctic Ocean is presented. The fractal geometry of the ice-sheets limited by leads and ridges was assessed using the satellite images, while the data on the correlated sea-ice motion were obtained in the research stations "North Pole 32" and "North Pole 33" established on the ice pack. The revealed decrease of the fractal dimension as a result of large-scale fragmentation is consistent with the localization of the fracture process (leads propagation). At the same time, the scaling properties of the distribution of amplitudes of ice-fields accelerations were insensitive to the event of sea-ice fragmentation. The temporal distribution of the accelerations was scale-invariant during "quiet" periods of sea-ice drift but disordered in the period of mechanical perturbation. The period of decorrelated (in time) ice-field motion during the important fracture event was interpreted as an inter-level transition in the hierarchic dynamical system. The mechanism of the long-range correlations in the sea-ice cover, including the fracture process, is suggested to be in relation with the self-organized oscillation dynamics inherent in the ice pack
Sensitivity and Accuracy of the Systems for the Magnetic Measurements of the LHC Magnets at CERN
Beam optics of the LHC accelerator require stringent control of the field quality of the main dipole and quadrupole magnets. The field quality measurements need challenging accuracy given the small size of the aperture (50 mm) : relative strength of the magnets within 2×10-4, harmonics in the ppm range, axis determination within 0.1 mm, main field direction within 0.2 mrad. We present a detailed analysis of the accuracy and reproducibility obtained with the equipment presently available for the qualification tests of the first series magnets
A Tool for Simulating Rotating Coil Magnetometers
When investigating the quality of a magnetic measurement system, one observes difficulties to identify the "trouble maker" of such a system as different effects can yield similar influences on the measurement results.We describe a tool in this paper that allows to investigate numerically the effects produced by different imperfections of components of such a system, including, but not limited to vibration and movements of the rotating coil, influence of electrical noise on the system, angular encoder imperfections. This system can simulate the deterministic and stochastic parts of those imperfections. We outline the physical models used that are generally based on experience or first principles. Comparisons to analytical results are shown. The modular structure of the general design of this tool permits to include new modules for new devices and effects
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