892 research outputs found
Light bending by nonlinear electrodynamics under strong electric and magnetic field
We calculate the bending angles of light under the strong electric and
magnetic fields by a charged black hole and a magnetized neutron star according
to the nonlinear electrodynamics of Euler-Heisenberg interaction. The bending
angle of light by the electric field of charged black hole is computed from
geometric optics and a general formula is derived for light bending valid for
any orientation of the magnetic dipole. The astronomical significance of the
light bending by magnetic field of a neutron star is discussed.Comment: drastically revised with conclusion change, reference added, version
to appear in JCA
Measurement of and Structure Functions in Low Region with the IHEP-JINR Neutrino Detector
The isoscalar structure functions and are measured as functions
of averaged over all permissible for the range of 6 to 28 GeV of
incident neutrino (anti-neutrino) energy at the IHEP-JINR Neutrino Detector.
The QCD analysis of structure function provides
MeV under the assumption of QCD
validity in the region of low . The corresponding value of the strong
interaction constant agrees with the
recent result of the CCFR collaboration and with the combined LEP/SLC result.Comment: 11 pages, 1 Postscript figure, LaTeX. Talk given at the 7th
International Workshop on Deep Inelastic Scattering and QCD (DIS 99),
Zeuthen, Germany, 19-23 Apr 199
Aspects of Magnetic Field Configurations in Planar Nonlinear Electrodynamics
In the framework of three-dimensional Born-Infeld Electrodynamics, we pursue
an investigation of the consequences of the space-time dimensionality on the
existence of magnetostatic fields generated by electric charges at rest in an
inertial frame, which are present in its four-dimensional version. Our analysis
reveals interesting features of the model. In fact, a magnetostatic field
associated with an electric charge at rest does not appear in this case.
Interestingly, the addition of the topological term (Chern-Simons) to
Born-Infeld Electrodynamics yields the appearance of the magnetostatic field.
We also contemplate the fields associated to the would-be-magnetic monopole in
three dimensions.Comment: 8 page
Экспериментальное обоснование установки ацетабулярного компонента с недопокрытием при эндопротезировании пациентов с тяжелой степенью дисплазии
Purpose. Estimation of critical value of acetabular component uncoverage enabling its implantation without an additional support. Methods. A comparative analysis of an original method for intraoperative measurement of uncoverage space of acetabular component based on the measurement of the depth of uncovered sector with X-ray control by the same technique was carried out. Mathematical computer modeling based on the finite element techniqueand the mechanical experiment were performed. Critical values of uncoverage enabling safe primary fixation of acetabular component were estimated in designed models. Results. High rate of coincidence of direct intraoperative and postoperative measurements by radiograms was obtained, testifying to the possibility of application of this technique of uncoverage estimation at the stage of preoperative X-ray planning in patients with different degree of dysplasia. Using the finite element technique and the mechanical experiment on pelvis models, a possibility of mounting anacetabular component with moderate uncoverage within 25% without screws and with significant uncoverage to 35% with additional two screws fixation was demonstrated.Цель работы - определение критической величины недопокрытия ацетабулярного компонента, при которой возможна его имплантация без использования дополнительной опоры. Методы. Проведен сравнительный анализ оригинального способа интраоперационного измерения площади недопокрытия вертлужного компонента, основанного на измерении глубины непокрытого сектора, с рентгеновской оценкой тем же способом. Осуществлены математическое компьютерное моделирование на основе метода конечных элементов и механический эксперимент. В разработанных моделях определялись критические величины недопокрытия, при которых возможно обеспечение надежной первичной фиксации ацетабулярного компонента Результаты. Выявлена высокая степень совпадения прямых интраоперационных и послеоперационных измерений по рентгенограммам, что свидетельствует о возможности применения данного метода оценки недопокрытия на этапе предоперационного рентгеновского планирования у пациентов с различной степенью дисплазии. С помощью метода конечных элементов и механического эксперимента на моделях таза показана возможность установки ацетабулярного компонента с умеренным недопокрытием в пределах 25% без винтов и со значительным недопокрытием до 35% с дополнительной фиксацией двумя винтами
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
Probing For New Physics and Detecting non linear vacuum QED effects using gravitational wave interferometer antennas
Low energy non linear QED effects in vacuum have been predicted since 1936
and have been subject of research for many decades. Two main schemes have been
proposed for such a 'first' detection: measurements of ellipticity acquired by
a linearly polarized beam of light passing through a magnetic field and direct
light-light scattering. The study of the propagation of light through an
external field can also be used to probe for new physics such as the existence
of axion-like particles and millicharged particles. Their existence in nature
would cause the index of refraction of vacuum to be different from unity in the
presence of an external field and dependent of the polarization direction of
the light propagating. The major achievement of reaching the project
sensitivities in gravitational wave interferometers such as LIGO an VIRGO has
opened the possibility of using such instruments for the detection of QED
corrections in electrodynamics and for probing new physics at very low
energies. In this paper we discuss the difference between direct birefringence
measurements and index of refraction measurements. We propose an almost
parasitic implementation of an external magnetic field along the arms of the
VIRGO interferometer and discuss the advantage of this choice in comparison to
a previously proposed configuration based on shorter prototype interferometers
which we believe is inadequate. Considering the design sensitivity in the
strain, for the near future VIRGO+ interferometer, of in the range 40 Hz Hz leads to a variable
dipole magnet configuration at a frequency above 20 Hz such that Tm/ for a `first' vacuum non linear QED detection
High Precision Mass Measurements in and Families Revisited
High precision mass measurements in and families performed
in 1980-1984 at the VEPP-4 collider with OLYA and MD-1 detectors are revisited.
The corrections for the new value of the electron mass are presented. The
effect of the updated radiative corrections has been calculated for the
and mass measurements.Comment: 5 pages, 1 table, submitted to Phys. Lett.
JINR activity in microwave sources for TeV range linear colliders
Results of theoretical and experimental studies of the microwave radiation sources on the base of the induction linac LIU-3000 (JINR, Dubna) are presented. In particular, a FEM-oscillator with the reversed guide magnetic field and Bragg resonator as well as an electron beam buncher in the two-beam accelerator (TBA) driver was studied
Inclusive production of charged pions in p+C collisions at 158 GeV/c beam momentum
The production of charged pions in minimum bias p+C interactions is studied
using a sample of 377000 inelastic events obtained with the NA49 detector at
the CERN SPS at 158 GeV/c beam momentum. The data cover a phase space area
ranging from 0 to 1.8 GeV/c in transverse momentum and from -0.1 to 0.5 in
Feynman x. Inclusive invariant cross sections are given on a grid of 270 bins
per charge thus offering for the first time a dense coverage of the projectile
hemisphere and of the cross-over region into the target fragmentation zone.Comment: 31 pages, 30 figures, submitted to European Journal of Physic
New data on OZI rule violation in bar{p}p annihilation at rest
The results of a measurement of the ratio R = Y(phi pi+ pi-) / Y(omega pi+
pi-) for antiproton annihilation at rest in a gaseous and in a liquid hydrogen
target are presented. It was found that the value of this ratio increases with
the decreasing of the dipion mass, which demonstrates the difference in the phi
and omega production mechanisms. An indication on the momentum transfer
dependence of the apparent OZI rule violation for phi production from the 3S1
initial state was found.Comment: 11 pages, 3 PostScript figures, submitted to Physics Letter
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