983 research outputs found
Modeling of thermal neutrons channeling in nanotubes with surface circular currents
The numerical simulation of thermal neutron channeling in conical and curved nanotubes with large circular surface currents is carried out. The coordinate distribution of neutrons from the impact parameters and the surface current
density is obtained. It is demonstrated that thermal neutrons can be focused after they have left the tube end. The condition for the retention of a neutron along the curved nanotube is obtained. The dependence of the surface current J on the neutron velocity V is found to be described by the correlation J = 1.465 × 10−5 V
Form of analyzing power and the determination of the basic parameters of hadron scattering amplitude
The determination of magnitudes of basic parameters of the high energy
elastic scattering amplitude are examined at small momentum transfers with
taking account of the Coulomb-hadron interference effects.Comment: 6 pages, LaTeX, 4 figures (files.ps), Talk at the International
Workshop "Spin and Symmetry" (Prague, Chech., 13-19 July 2000
Coulomb-hadron phase factor and spin phenomena in a wide region of transfer momenta
The Coulomb-hadron interference effects are examined at small and large .
The methods for the definition of spin-dependent parts of hadron scattering
amplitude are presented. The additional contributions to analyzing power
and the double spin correlation parameter owing to the
electromagnetic-hadron interference are determined in the diffraction dip
domain of high-energy elastic hadron scattering.Comment: 9 pages, LaTeX, 4 figure
Identification of particles with Lorentz factor up to with Transition Radiation Detectors based on micro-strip silicon detectors
This work is dedicated to the study of a technique for hadron identification
in the TeV momentum range, based on the simultaneous measurement of the
energies and of the emission angles of the Transition Radiation (TR) X-rays
with respect to the radiating particles. A detector setup has been built and
tested with particles in a wide range of Lorentz factors (from about to
about crossing different types of radiators. The measured
double-differential (in energy and angle) spectra of the TR photons are in a
reasonably good agreement with TR simulation predictions.Comment: 31 pages, 12 figures, paper published on Nuclear Instruments &
Methods
Double Spin Asymmetries A_NN and A_SS at sqrt{s}=200 GeV in Polarized Proton-Proton Elastic Scattering at RHIC
We present the first measurements of the double spin asymmetries A_NN and
A_SS at sqrt{s}=200 GeV, obtained by the pp2pp experiment using polarized
proton beams at the Relativistic Heavy Ion Collider (RHIC). The data were
collected in the four momentum transfer t range 0.01<|t|<0.03 (GeV/c)^2. The
measured asymmetries, which are consistent with zero, allow us to estimate
upper limits on the double helicity-flip amplitudes phi_2 and phi_4 at small t
as well as on the difference Delta(sigma_T) between the total cross sections
for transversely polarized protons with antiparallel or parallel spin
orientations.Comment: 13 pages with 3 figures. Final version accepted by Phys. Lett.
First Measurement of A_N at sqrt(s)=200 GeV in Polarized Proton-Proton Elastic Scattering at RHIC
We report on the first measurement of the single spin analyzing power (A_N)
at sqrt(s)=200GeV, obtained by the pp2pp experiment using polarized proton
beams at the Relativistic Heavy Ion Collider (RHIC). Data points were measured
in the four momentum transfer t range 0.01 < |t| < 0.03 (GeV/c)^2. Our result,
averaged over the whole t-interval is about one standard deviation above the
calculation, which uses interference between electromagnetic spin-flip
amplitude and hadronic non-flip amplitude, the source of A_N. The difference
could be explained by an additional contribution of a hadronic spin-flip
amplitude to A_N.Comment: 13 pages, 5 figures. New values of polarization errors. Final version
submitted to Phys. Lett.
Diffraction radiation from a charge as radiation from a superluminal source in a vacuum
An analysis of spectral-angular characteristics of diffraction radiation, both incoherent and coherent, has been performed. It is shown that radiation processes can be inter-preted as Cherenkov radiation, which is produced by a region of dynamic polarization moving along a target edge with super-luminal velocity vS
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