2,614 research outputs found
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
Evidence for an Excited Hyperon State in pp -> p K^+ Y^{0*}
Indications for the production of a neutral excited hyperon in the reaction
pp -> p K^+ Y^{0*} are observed in an experiment performed with the ANKE
spectrometer at COSY-J\"ulich at a beam momentum of 3.65 GeV/c. Two final
states were investigated simultaneously, viz. Y^{0*} -> pi^+X^- and pi^-X^+,
and consistent results were obtained in spite of the quite different
experimental conditions. The parameters of the hyperon state are M(Y^{0*})=
(1480 +/- 15) MeV/c^2 and Gamma(Y^{0*})= (60 +/- 15) MeV/c^2. The production
cross section is of the order of few hundred nanobarns. Since the isospin of
the Y^{0*} has not been determined here, it could either be an observation of
the Sigma(1480), a one-star resonance of the PDG tables, or alternatively a
Lambda hyperon. Relativistic quark models for the baryon spectrum do not
predict any excited hyperon in this mass range and so the Y^{0*} may be of
exotic nature.Comment: 4 pages, 3 figures, accepted for publication in Phys.Rev.Let
Overcoming synecdoche: why practice development and quality improvement approaches should be better integrated
Commentary on: Lavery, G. (2016) Quality improvement – rival or ally of practice development? International Practice Development Journal. Vol. 6. No. 1. Article 1
RV POSEIDON Cruise Report POS420 COWACSS Biological observation and sampling of cold-water corals to investigate impacts on climate change
Trondheim – (Kristiansund) – Kiel
08. – (25.) – 30.09.201
The ABC Effect in Double-Pionic Nuclear Fusion and a pn Resonance as its Possible Origin
The ABC effect -- a long-standing puzzle in double-pionic fusion -- has been
reexamined by the first exclusive and kinematically complete measurements of
solid statistics for the fusion reactions , He and He using the WASA detector, first at
CELSIUS and recently at COSY -- the latter with a statistics increased by
another two orders of magnitude. In all cases we observe a huge low-mass
enhancement in the -invariant mass accompanied by a pronounced
excitation. For the most basic fusion reaction, the reaction, we observe in addition a very pronounced resonance-like
energy dependence in the total cross section with a maximum 90 MeV below the
mass and a width of only 50 MeV, which is five times smaller
than expected from a conventional -channel excitation. This
reveals the ABC effect to be the consequence of a s-channel resonance with the
formfactor of this dibaryonic state being reflected in the low-mass enhancement
of the -invariant mass. From the fusion reactions to He and He
we learn that this resonance is robust enough to survive even in nuclei.Comment: conference proceedings PANIC 0
\u27Trust\u27 and \u27confidence\u27 as socio-technical problems in the transformation of energy systems
Background: For the development of a sustainable energy system, the public’s contribution to the sustainment of the system’s current operations will become vital. The public’s role is expected to change from that of passive service abiders to active service providers, as anticipated by visions of prosumers, smart grids, demand side management, virtual power plants, and electric vehicle management. Smart technology and new business models will increase system complexity and the experience of uncertainty and risk for all parties. Actionability of the public’s participation in the opportunities arising from the transformation of energy systems will become a problem.
Methods: With a qualitative functionalist method, we analyze the prerequisites of the public’s participation: the capacity of social mechanisms, such as trust, for the solution of social problems. Functional problems affect the continuation of communication, i.e., the possibility of the sustainment of social reality. We isolate three case studies that illustrate concrete effects of trust, distrust, and confidence on three parties, respectively: consumers, investors, and those affected by grid extensions.
Results and conclusions: We argue that the social mechanisms of trust and confidence are more vital for consumers, investors, and those affected than previous research has noticed. These mechanisms determine the achievement of sustainability in energy systems by sustaining actionability as a favorable expectation (trust, confidence), or an unfavorable expectation (lack of trust, distrust). Even lack of trust and distrust can be valuable contributors on the road to sustainability, since they uncover flaws and setbacks of a fledgling smart grid
Production of -mesons in pp and pn reactions
We investigate the cross section for the reaction near
threshold and at medium energies. An effective Lagrangian approach with
one-pion exchange is applied to analyze different contributions to the cross
section for different isospin channels. The Reggeon exchange mechanism is also
considered. The results are used to calculate the contribution of the
meson to the cross sections and invariant mass distributions of the
reactions and . It is found that the
experimental observation of mesons in the reaction is much more promising than the observation of mesons in the
reaction .Comment: 26 pages, including 11 eps figures, to be bublished in J. Phys.
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