236 research outputs found
Regulation of Transfer of 137cs by Polymeric Sorbents for Grow Ecologically Sound Biomass
Soil contamination with radiocesium has a long-term radiological impact due to its long physical half-life (30.1 years for 137Cs and 2 years for 134Cs) and its high biological availability. 137Cs causes the largest concerns because of its deleterious effect on agriculture and stock farming, and, thus, human life for decades. One of the important aspects of the problem of contaminated soils remediation is understand of protective actions aimed at the reduction of biological migration of radionuclides in soil-plant system. The most effective way to bind radionuclides is the use of selective sorbents. The proposed research mainly aims to achieve control on transfer of 137Cs in a system growing media–plant due to counter ions variation in the polymeric sorbents. As the research object, Japanese basil-Perilla frutescens was chosen. Productivity of plants depending on the presence (control-without presence of polymer) and type of polymer material, as well as content of 137Cs in plant material has been determined. The character of different polymers influences on the 137Cs migration in growing media–plant system as well as accumulation in the plants has been cleared up
Pion and Vector Meson Form Factors in the Kuperstein-Sonnenschein holographic model
We study phenomenological aspects of the holographic model of chiral symmetry
breaking recently introduced by Kuperstein and Sonnenschein (KS). As a first
step, we calculate the spectrum of vector and axial-vector mesons in the KS
model. We numerically compute various coupling constants of the mesons and
pions. Our analysis indicates that vector meson dominance is realized in this
model. The pion, vector meson and axial-vector meson form factors are obtained
and studied in detail. We find good agreement with QCD results. In particular,
the pion form factor closely matches available experimental data.Comment: v1: 27 pages, 9 figures, 4 tables; v2: minor changes, added more
general discussion of vector meson dominance; v3: minor changes and
additions, version accepted for publication in JHE
Study of the A(e,e') Reaction on H, H, C, Al, Cu and Au
Cross sections for the p()n process on H, H, C,
Al, Cu and Au targets were measured at the Thomas
Jefferson National Accelerator Facility (Jefferson Lab) in order to extract the
nuclear transparencies. Data were taken for four-momentum transfers ranging
from =1.1 to 4.8 GeV for a fixed center of mass energy of =2.14
GeV. The ratio of and was extracted from the measured
cross sections for H, H, C and Cu targets at = 2.15
and 4.0 GeV allowing for additional studies of the reaction mechanism. The
experimental setup and the analysis of the data are described in detail
including systematic studies needed to obtain the results. The results for the
nuclear transparency and the differential cross sections as a function of the
pion momentum at the different values of are presented. Global features
of the data are discussed and the data are compared with the results of model
calculations for the p()n reaction from nuclear targets.Comment: 28 pages, 19 figures, submited to PR
Measurements of electron-proton elastic cross sections for
We report on precision measurements of the elastic cross section for
electron-proton scattering performed in Hall C at Jefferson Lab. The
measurements were made at 28 unique kinematic settings covering a range in
momentum transfer of 0.4 5.5 . These measurements
represent a significant contribution to the world's cross section data set in
the range where a large discrepancy currently exists between the ratio of
electric to magnetic proton form factors extracted from previous cross section
measurements and that recently measured via polarization transfer in Hall A at
Jefferson Lab.Comment: 17 pages, 18 figures; text added, some figures replace
Measurement of Nuclear Transparency for the A(e,e' pi^+) Reaction
We have measured the nuclear transparency of the A(e,e' pi^+) process in
^{2}H,^{12}C, ^{27}Al, ^{63}Cu and ^{197}Au targets. These measurements were
performed at the Jefferson Laboratory over a four momentum transfer squared
range Q^2 = 1.1 - 4.7 (GeV/c)^2. The nuclear transparency was extracted as the
super-ratio of from data to a model of
pion-electroproduction from nuclei without pi-N final state interactions. The
Q^2 and atomic number dependence of the nuclear transparency both show
deviations from traditional nuclear physics expectations, and are consistent
with calculations that include the quantum chromodynamical phenomenon of color
transparency.Comment: 5 pages, 3 figs Changes to figure 2 and 3 (error band updated and
theory curves updated
A Measurement of the Electric Form Factor of the Neutron through at (GeV/c)
We report the first measurement of the neutron electric form factor
via using a solid polarized target. was
determined from the beam-target asymmetry in the scattering of longitudinally
polarized electrons from polarized deuterated ammonia, ND. The
measurement was performed in Hall C at Thomas Jefferson National Accelerator
Facility (TJNAF) in quasi free kinematics with the target polarization
perpendicular to the momentum transfer. The electrons were detected in a
magnetic spectrometer in coincidence with neutrons in a large solid angle
segmented detector. We find at (GeV/c).Comment: Latex2e 5 pages, 3 figure
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