33 research outputs found
The study of the negative pion production in neutron-proton collisions at beam momenta below 1.8 GeV/c
A detailed investigation of the reaction np -> pp\pi^{-} has been carried out
using the data obtained with the continuous neutron beam produced by charge
exchange scattering of protons off a deuterium target. A partial wave
event-by-event based maximum likelihood analysis was applied to determine
contributions of different partial waves to the pion production process. The
combined analysis of the np -> pp\pi^{-} and pp -> pp\pi^{0} data measured in
the same energy region allows us to determine the contribution of isoscalar
partial waves (I=0) in the momentum range from 1.1 up to 1.8 GeV/c. The decay
of isoscalar partial waves into (^1S_0)_{pp}\pi$ channel provides a good tool
for a determination of the pp S-wave scalar scattering length in the final
state which was found to be a_{pp}=-7.5\pm 0.3 fm.Comment: 6 pages, 6 figure
Observation of strong final-state effects in pi+ production in pp collisions at 400 MeV
Differential cross sections of the reactions and have been measured at MeV by detecting the charged
ejectiles in the angular range . The
deduced total cross sections agree well with those published previously for
neighbouring energies. The invariant mass spectra are observed to be strongly
affected by production and final-state interaction. The data are
well described by Monte Carlo simulations including both these effects. The
ratio of and cross sections also compares
favourably to a recent theoretical prediction which suggests a dominance of
-production in the relative -state.Comment: 17 pages, 5 figure
Production of the 1S0 diproton in the pp -> pp pi0 reaction at 0.8 GeV
The pp -> pp pi0 differential cross section has been measured with the ANKE
spectrometer at COSY-Juelich for pion cms angles between 0 and 15.4 degrees at
a proton beam energy of 0.8 GeV. The selection of diproton pairs with an
excitation energy E_{pp} < 3 MeV ensures that the final pp system is dominantly
in the spin-singlet 1S0 state. The kinematics are therefore very similar to
those of pp -> d pi+ but with different spin and isospin transitions. The
results will thus provide a crucial extra test of pion production models in
nucleon-nucleon collisions.
The cross sections, which are over two orders of magnitude smaller than those
of pp -> d pi+, show a forward dip, even stronger than that seen at lower
energies. This behaviour is well reproduced in a theoretical model that
includes P-wave Delta-N states.Comment: 10 pages, 5 eps figures, prepared using elsart.cl
Dependence of pp->pp pi0 near Threshold on the Spin of the Colliding Nucleons
A polarized internal atomic hydrogen target and a stored, polarized beam are
used to measure the spin-dependent total cross section Delta_sigma_T/sigma_tot,
as well as the polar integrals of the spin correlation coefficient combination
A_xx-A_yy, and the analyzing power A_y for pp-> pp pi0 at four bombarding
energies between 325 and 400 MeV. This experiment is made possible by the use
of a cooled beam in a storage ring. The polarization observables are used to
study the contribution from individual partial waves.Comment: 6 pages, 1 table, 4 figures, corrected equations 2 and
TOPAS 2 - ein hochaufloesendes Taggingsystem am Bonner SAPHIR-Detektor
SIGLECopy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
Messverfahren zur Bestimmung von Traegheitsmomenten und Traegheitsachsen von Aggregaten und Fahrzeugen
TIB: AC 8705+MF / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman