524 research outputs found
The Pion-Nucleon coupling constant from np charge exchange scattering
A novel extrapolation method has been used to deduce the charged Pion-Nucleon
coupling constant from backward differential scattering cross sections. We
applied it to new measurements performed at 162 MeV at the The Svedberg
Laboratory in Uppsala. In the angular range , the
carefully normalized data are steeper than those of most previous measurements.
The extracted value, , in good agreement with
the classical value, is higher than those determined in recent nucleon-nucleon
partial-wave analyses.Comment: 6 pages, 3 encapsulated figures, epsfig, menu97.cls (included
Light-ion production in the interaction of 96 MeV neutrons with oxygen
Double-differential cross sections for light-ion (p, d, t, He-3 and alpha)
production in oxygen, induced by 96 MeV neutrons are reported. Energy spectra
are measured at eight laboratory angles from 20 degrees to 160 degrees in steps
of 20 degrees. Procedures for data taking and data reduction are presented.
Deduced energy-differential and production cross sections are reported.
Experimental cross sections are compared to theoretical reaction model
calculations and experimental data at lower neutron energies in the literature.
The measured proton data agree reasonably well with the results of the model
calculations, whereas the agreement for the other particles is less convincing.
The measured production cross sections for protons, deuterons, tritons and
alpha particles support the trends suggested by data at lower energies.Comment: 21 pages, 13 figures, submitted to Phys. Rev.
Precise strength of the NN coupling constant
We report here a preliminary value for the piNN coupling constant deduced from the GMO sumrule for forward piN scattering. As in our previous determination from np backward differential scattering cross sections we give a critical discussion of the analysis with careful attention not only to the statistical, but also to the systematic uncertainties. Our preliminary evaluation gives (GMO) = 13.99(24)
Nucleon-induced fission cross-sections of tantalum and separated tungsten isotopes and "compound nucleus" effect in intermediate energy region
Neutron- and proton-induced fission cross-sections of separated isotopes of
tungsten (182W, 183W, 184W, and 186W) and 181Ta relative to 209Bi have been
measured in the incident nucleon energy region 50 - 200 MeV using fission
chambers based on thin-film breakdown counters (TFBC) using quasi-monoenergetic
neutrons from the 7Li(p,n) reaction and at the proton beams of The Svedberg
Laboratory (TSL), Uppsala University (Uppsala, Sweden). The results are
compared with predictions by the CEM03.01 event generator, as well as with the
recent data for nuclei in the lead-bismuth region. The effect of "compound
nucleus" in the intermediate energy region is discussed, displaying in
exponential dependence of nucleon-induced fission cross-sections on the
parameter Z^2/A of the composite system (projectile+target nucleus), and in
other characteristics of the fission process for which parameter Z^2/A plays a
role similar to the one of the usual liquid-drop parameter Z^2/A of compound
nuclei.Comment: 4 pages, 3 figures, 2 tables, only pdf file, to be published in Proc.
Int. Conf. on Nucl. Data for Sci. and Technology (ND2007), Nice, France,
April 22-27, 200
Light-ion Production And Fission Studies Using The Medley Facility At Tsl
oS(FNDA2006)001 © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence
Measurement of the Absolute Differential Cross Section for np Elastic Scattering at 194 MeV
A tagged medium-energy neutron beam has been used in a precise measurement of
the absolute differential cross section for np back-scattering. The results
resolve significant discrepancies within the np database concerning the angular
dependence in this regime. The experiment has determined the absolute
normalization with 1.5% uncertainty, suitable to verify constraints of
supposedly comparable precision that arise from the rest of the database in
partial wave analyses. The analysis procedures, especially those associated
with evaluation of systematic errors in the experiment, are described in detail
so that systematic uncertainties may be included in a reasonable way in
subsequent partial wave analysis fits incorporating the present results.Comment: 22 pages, 21 figures, submitted for publication in Physical Review
Precise strength of th piNN coupling constant
We report here a preliminary value for the piNN coupling constant deduced
from the GMO sumrule for forward piN scattering. As in our previous
determination from np backward differential scattering cross sections we give a
critical discussion of the analysis with careful attention not only to the
statistical, but also to the systematic uncertainties. Our preliminary
evaluation gives (GMO) = 13.99(24).Comment: 4 pages, 1 figure, contribution to INPC/98, to be published in
Conference Proceedings, Nuclear Physics A (Conference Proceedings
Measurement of the Absolute np Scattering Differential Cross Section at 194 MeV
We describe a double-scattering experiment with a novel tagged neutron beam
to measure differential cross sections for np back-scattering to better than 2%
absolute precision. The measurement focuses on angles and energies where the
cross section magnitude and angle-dependence constrain the charged pion-nucleon
coupling constant, but existing data show serious discrepancies among
themselves and with energy-dependent partial wave analyses (PWA). The present
results are in good accord with the PWA, but deviate systematically from other
recent measurements.Comment: 4 pages, 4 figure
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