938 research outputs found
Two-proton correlation function: a gentle introduction
The recent COSY-11 collaboration measurement of the two-proton correlation
function in the pp -> ppeta reaction, reported at this meeting [1], arouse some
interest in a simple theoretical description of the correlation function. In
these notes we present a pedagogical introduction to the practical methods that
can be used for calculating the correlation function.Comment: Prepared for the proceedings of the Symposium on Meson Physics at
COSY-11 and WASA-at-COSY, Krakow, Poland, 17-22 June 200
COSY-11 : How will we remember it ?
A personal selection is made of the highlights of the COSY-11 physics program
undertaken at the COoler SYnchrotron of the Forschungszentrum Juelich. This has
been particularly rich in the field of strange and non-strange meson production
in proton-proton and proton-deuteron collisions. The results are considered in
relation to experiments carried out at other facilities and with respect to
their impact on theory.Comment: Invited talk at the "Symposium on Meson Physics at COSY--11", Cracow,
June 2007. 14 pages + 12 eps figures. AIP conference styl
production in proton-proton collisions far from the threshold
I discuss exclusive production of the meson in the
reaction far from the threshold. The contribution of diffractive component as
well as that for fusion are calculated. In the
first case the formalism of unintegrated gluon distribution functions (UGDF) is
used. The distributions in the Feynman (or rapidity), transferred
four-momenta squared between initial and final protons (, ) and
azimuthal angle difference between outgoing protons () are calculated.
The deviations from the dependence predicted by one-step
vector-vector-pseudoscalar coupling are quantified and discussed. The results
are compared with the results of the WA102 collaboration at CERN. Most of the
models of UGDF from the literature give too small cross section as compared to
the WA102 data and predict angular distribution in relative azimuthal angle
strongly asymmetric with respect to in disagreement with the WA102
data. This points to a different mechanism at the WA102 energy. Predictions for
RHIC, Tevatron and LHC are given.Comment: 7 pages, 6 figures and 1 table invited talk at the symposium on meson
physics at COSY11 and WASA-at-COSY, Cracow, Poland, June 17-22, 200
Physics of EtaPrime->Pi+Pi-Eta and EtaPrime->Pi+Pi-Pi0 decays
The article describes experimental status of EtaPrime->Pi+Pi-Eta and
EtaPrime->Pi+Pi-Pi0 decays. A theoretical framework used for description of the
decays mechanism is also reviewed. The possibilities for the measurements with
WASA-at-COSY are mentioned.Comment: Proceedings from Symposium on Meson Physics at COSY-11 and
WASA-at-COSY, Cracow, 17-22 June 200
Summary of the COSY-11 Measurements of Hyperon Production
The studies of hyperon production performed at COSY-11 are summarized. The
results of the experiments in the reaction channels pp-->pK+Lambda,
pp-->pK+Sigma0, and pp-->nK+Sigma+ are shown. Excitation functions
fromthreshold up to about 90MeV excess energies have been evaluated with high
precision for the Lambda and Sigma0 production. The Lambdap and Sigma0p final
state interactions were extracted. The Sigma+ production was measured at 13 and
60 MeV excess energies.Comment: 8 pages, 4 figures, Talk given at Symposium on Meson Physics at
COSY-11 and WASA-at-COSY, Cracow, Poland, 17-22 Jun 200
What is interesting in eta and eta' Meson Decays?
An introduction to the physics of eta and eta' meson decays is given. A
historical account of the discovery of the mesons is presented. It is followed
by an overview and classification of the common decay modes and the relevance
of the mesons for modern hadron and particle physics. In more detail the
hadronic decay modes are discussed and in particular some interesting features
of the eta-> 3pi0 decay are presented. The last section briefly reviews and
compares reactions used to produce the eta and eta' mesons for the studies of
their decays.Comment: 15 pages, 5 figures,prepared for Symposium on Meson Physics at
COSY-11 and WASA-at-COSY, Cracow, 17-22 June 2007; added reference
Leptonic decays of the eta meson with the WASA detector at CELSIUS
Decay channels of the eta meson with at least one lepton pair in the final
state are discussed. Preliminary results on electron-positron pair production
from the pd->He eta reaction from the WASA experiment at CELSIUS are presented.Comment: 8 pages, 7 figures, prepared for Symposium on Meson Physics at
COSY-11 and WASA-at-COSY, Cracow, 17-22 June 200
Luminosity determination for the quasi-free nuclear reactions
A method for the calculation of the luminosity for the proton-nucleus
collisions based on the quasi-free proton-proton scattering is presented. As an
example of application the integrated luminosity for the scattering of protons
off the deuteron target is determined for the experiment of the quasi-free pn
--> pneta reaction performed by means of the COSY-11 facility.Comment: 7 pages, 5 figures, Presented at Symposium on Meson Physics at
COSY-11 and WASA-at-COSY, Cracow, Poland, 17-22 Jun 200
What can we learn about light-meson interactions at electron-positron colliders?
Precision studies at electron-positron colliders with center-of-mass energies
in the charm-tau region and below have strongly contributed to our
understanding of light-meson interactions at low energies. We focus on the
processes involving two or three light mesons with invariant masses below
nucleon-antinucleon threshold. A prominent role is given to the interactions of
the nine lightest pseudoscalar mesons (pions, kaons, , and ) and
the two narrow neutral isoscalar vector mesons and .
Experimental methods used to produce the mesons are reviewed as well as theory
tools to extract properties of the meson-meson interactions. Examples of recent
results from the DANE, BEPCII, and VEPP-2000 colliders are presented. In
the outlook we briefly discuss prospects for further studies at future
super-charm-tau factories.Comment: 132 pages, 74 figures (v2: typos corrected, references updated,
corresponds to the published version
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