1,067 research outputs found
ADR That is Out of This World: A Regime for the Resolution of Outer-Space Disputes
The United States’ interest in enlarging and increasing its presence in outer space is an extension of its current geographically extensive military presence around the globe. These outer-space exploratory goals are compared to the expansionist aspirations of ocean-born European empires of the 17th and 18th centuries; and therefore project a future where nations will compete over space-control to gain a geostrategic advantage on Earth
Meson-production experiments at COSY-Juelich
Selected results from experiments at COSY-Juelich are presented: an attempt
to measure the mass of the eta meson with high precision (ANKE facility), first
steps towards the detection of rare eta decays (WASA), and several measurements
of KKbar-pair production (ANKE, COSY-11, MOMO).Comment: Proceedings of QNP2009, Beijing, Sept. 2009; to be published in
Chinese Physics C. 6 pages, 5 figure
Measurement of the invariant mass distributions for the pp -> ppeta' reaction at excess energy of Q = 16.4 MeV
The proton-proton and proton-eta' invariant mass distributions have been
determined for the pp -> ppeta' reaction at an excess energy of Q = 16.4 MeV.
The measurement was carried out using the COSY-11 detector setup and the proton
beam of the cooler synchrotron COSY. The shapes of the determined invariant
mass distributions are similar to those of the pp -> ppeta reaction and reveal
an enhancement for large relative proton-proton momenta. This result, together
with the fact that the proton-eta interaction is much stronger that the
proton-eta' interaction, excludes the hypothesis that the observed enhancement
is caused by the interaction between the proton and the meson
The energy dependence of the pp->K+ n Sigma+ reaction close to threshold
The production of the Sigma+ hyperon through the pp->K+nSigma+ reaction has
been investigated at four energies close to threshold, 1.826, 1.920, 1.958, and
2.020 GeV. At low energies, correlated K+pi+ pairs can only originate from
Sigma+ production so that their measurement allows the total cross section for
the reaction to be determined. The results obtained are completely consistent
with the values extracted from the study of the K+-proton correlation spectra
obtained in the same experiment. These spectra, as well as the inclusive K+
momentum distributions, also provide conservative upper limits on the Sigma+
production rates. The measurements show a Sigma+ production cross section that
varies roughly like phase space and, in particular, none of the three
experimental approaches used supports the anomalously high near-threshold
pp->K+ nSigma+ total cross section previously reported [T. Rozek et al., Phys.
Lett. B 643, 251 (2006)].Comment: Submitted to PR
Monitoring of the accelerator beam distributions for internal target facilities
We describe a direct method for monitoring the geometrical dimensions of a
synchrotron beam at the target position for internal target installations. The
method allows for the observation of the proton beam size as well as the
position of the beam relative to the target. As a first demonstration of the
technique, we present results obtained by means of the COSY-11 detection system
installed at the cooler synchrotron COSY. The influence of the stochastic
cooling on the COSY proton beam dimensions is also investigated.Comment: 7 pages, 8 figures, Submitted to Nucl. Inst. & Meth.
High precision beam momentum determination in a synchrotron using a spin resonance method
In order to measure the mass of the eta meson with high accuracy using the
d+p -> 3He+eta reaction, the momentum of the circulating deuteron beam in the
Cooler Synchrotron COSY of the Forschungszentrum Juelich has to be determined
with unprecedented precision. This has been achieved by studying the spin
dynamics of the polarized deuteron beam. By depolarizing the beam through the
use of an artificially induced spin resonance, it was possible to evaluate its
momentum p with a precision of dp/p < 10-4 for a momentum of roughly 3 GeV/c.
Different possible sources of error in the application of the spin resonance
method are discussed in detail and its possible use during a standard
experiment is considered.Comment: 10 pages, 6 figures, 2 tables, published versio
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