473 research outputs found
Study of amplifying characteristics of copper bromide active media operating at the increased superradiance pulse duration mode
Amplifying characteristics of the copper bromide vapor active media with the increased inversion duration are studied using the detailed kinetic modeling. The analysis of the gain radial profile and its time evolution at various points of the GDT profile is presented. The results show the possibility of application such active media to the tasks of the remote object visualization
Study of high-frequency brightness amplifiers radial profile
The paper presents experimental results on obtaining high pulse repetition frequencies of radiation/gain in copper bromide vapor active media. Also the results of experimental and theoretical studies of radial profiles of radiation and amplification of such media at raised pump pulse frequencies are give
Next-to-Leading Order perturbative QCD corrections to baryon correlators in matter
We compute the next-to-leading order perturbative QCD corrections to the
correlators of nucleon interpolating currents in relativistic nuclear matter.
The main new result is the calculation of the O(alpha_s) perturbative
corrections to the coefficient functions of the vector quark condensate in
matter. This condensate appears in matter due to the violation of Lorentz
invariance. The NLO perturbative QCD corrections turn out to be large which
implies that the NLO corrections must be included in a sum rule analysis of the
properties of both bound nucleons and relativistic nuclear matter.Comment: 19 pages in LaTeX, including 5 Postscript figure
Shadowing, Binding and Off-Shell Effects in Nuclear Deep Inelastic Scattering
We present a unified description of nuclear deep inelastic scattering (DIS)
over the whole region of the Bjorken variable. Our approach is based on
a relativistically covariant formalism which uses analytical properties of
quark correlators. In the laboratory frame it naturally incorporates two
mechanisms of DIS: (I) scattering from quarks and antiquarks in the target and
(II) production of quark-antiquark pairs followed by interactions with the
target. We first calculate structure functions of the free nucleon and develop
a model for the quark spectral functions. We show that mechanism (II) is
responsible for the sea quark content of the nucleon while mechanism (I)
governs the valence part of the nucleon structure functions. We find that the
coherent interaction of pairs with nucleons in the nucleus leads to
shadowing at small and discuss this effect in detail. In the large
region DIS takes place mainly on a single nucleon. There we focus on the
derivation of the convolution model. We point out that the off-shell properties
of the bound nucleon structure function give rise to sizable nuclear effects.Comment: 29 pages (and 10 figures available as hard copies from Authors),
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