1,394 research outputs found
Pion Compton scattering and bremsstrahlung
The pion-polarizability functions are structure functions of pion-Compton
scattering. They can be assessed in high-energy pion-nucleus bremsstrahlung
reactions, . We present numerical expectations for
pion-nucleus bremsstrahlung cross sections in the Coulomb region, i.e. the
small-angle region where the nuclear scattering is dominated by the Coulomb
interaction. We investigate the prospects of measuring the polarizability
functions for pion-Compton c.m. energies from threshold up to 1 GeV. A
meson-exchange model is used for the pion-Compton amplitude.Comment: 20 pages, 11 figure
Hard pion bremsstrahlung in the Coulomb region
Hard high-energy pion-nucleus bremsstrahlung, ,
is studied in the Coulomb region, i.e. the small-angle region where the nuclear
scattering is dominated by the Coulomb interaction. Special attention is
focussed on the possibility of measuring the pion polarizability in such
reactions. We study the sensitivity to the structure of the underlying the
pion-Compton amplitude through a model with , , and a_1
exchanges. It is found that the effective energy in the virtual pion-Compton
scattering is often so large that the threshold approximation does not apply.Comment: 18 pages, 5 figure
Wie es zur Wirtschafts-, Währungs- und Sozialunion kam : Wirtschaftliche Voraussetzungen und politische Vorbedingungen
Es gab, so verkünden seit nunmehr zwei Jahrzehnten die bundesdeutschen Medien, zum Zeitpunkt und zur Art und Weise, wie die Wirtschafts- und Währungsunion vollzogen wurde, keine Alternative. «Ich kenne keine ernsthafte Betrachtung, wie man es hätte anders machen können», äußerte sich der Chefunterhändler des Einigungsvertrages Wolfgang Schäuble in einem Interview im «Neuen Deutschland» im Mai 2009.
Bezogen auf jene programmatischen Konzepte, die die Währungsunion im Transformationsprozess der DDR-Wirtschaft bzw. im Einigungsprozess anders platzieren wollten, stimmt Schäubles Aussage offensichtlich nicht. Doch siegte mit dem «Stichwortkonzept: Schritte zur deutschen Wirtschaftseinheit
» das bessere Programm? Welche Motive hatten Kanzler Kohl bzw. Finanzminister Waigel die Währungsunion an den Beginn des wirtschaftpolitischen Transformationsprozesses in der DDR zu setzen? Glaubten beide wirklich, sich für das bessere, d. h. für die DDR-Bürger und für das Zusammenwachsen von DDR und BRD günstigere Konzept entschieden zu haben? Warum verweigerten sie sich so vehement jedem Vorschlag ausgewiesener Experten, die Transformation von der Planwirtschaft zur Marktwirtschaft in Ostdeutschland über mehrere Jahre statt über einige Monate zu vollziehen? Vermutlich ging es dem Bundeskanzler nur um eins – um den Machterhalt. Nur als «Kanzler der Einheit», hatte er alle Chancen
im Herbst 1990 die anstehenden Bundestagswahlen zu gewinnen. So hat er das natürlich in seinen Memoiren nicht formuliert
Coulomb-nuclear interference in pion-nucleus bremsstrahlung
Pion-nucleus bremsstrahlung offers a possibility of measuring the structure
functions of pion-Compton scattering from a study of the
small-momentum-transfer region where the bremsstrahlung reaction is dominated
by the single-photon-exchange mechanism. The corresponding cross-section
distribution is characterized by a sharp peak at small momentum transfers. But
there is also a hadronic contribution which is smooth and constitutes an
undesired background. In this communication the modification of the
single-photon exchange amplitude by multiple-Coulomb scattering is investigated
as well as the Coulomb-nuclear interference term.Comment: 21 pages, 5 figures. Eqs.(51,52) corrected; some new figure
Experiences from Implementation of Lean Production: Standardization versus Self-management: A Swedish Case Study
In this article, we discuss important aspects of the perceived problematic relationship between self-management and standardization. The article presents data from three case studies conducted within manufacturing companies in Sweden, where the popularity of lean production has led to a renaissance for short-cycle and standardized assembly work in settings that traditionally have made use of sociotechnical production design. The data suggest that the implementation has not contributed to an increased commitment, smooth operations, and capacity for change and innovation. Despite these not so positive results, it is argued that it is possible to combine self-management principles with lean production and standardization if 1) the implementation of lean is done with a contextual sensitivity, 2) a balance is reached between the use of standards on the one hand and work enrichment on the other, and 3) a feeling of ownership as regards both implementation and production process is upheld among the product on personnel
Multi-particle emission from 31Ar at IDS
XXXV Bienal de la RSEF, Gijón (España), 13-17 de Julio de 2015; http://bienalrsef-gijon2015.org/web/Acknowledge the support received from the Spanish research council under
project FPA2012-32443 and FPI 2013 grant BES-2013-066348.Peer Reviewe
After-action Analysis of the Magic Maggiore Workshop on Expert Support and Reachback
The European Commission’s Joint Research Centre (JRC) in collaboration with the Global Initiative to Combat Nuclear Terrorism (GICNT) organized a two and a half-day workshop on expert support and reachback entitled Magic Maggiore at the JRC Ispra, Italy in 28-30 March 2017.
Through a series of presentations, case studies, panel discussions, and a demonstration exercise, Magic Maggiore helped raise awareness and build commitment towards technical reachback. Furthermore, the workshop presented best practices to address key challenges, and identified areas for future work in this field. The workshop included a real-time detection and reachback exercise of a hypothetical nuclear security incident, put on between the JRC (Ispra) and France (Paris). The demonstration focused on core components of alarm adjudication and information exchange between front line officers, a national reachback centre, and an advanced centralised reachback centre located in Paris.
A list of concrete post-workshop activities has been generated. The purpose of the list is to pave the way for the identification of the next steps towards development of European capabilities for nuclear security and in more general, for CBRNE security.
Reachback is necessary for alarm adjudication to provide timely information for a balanced response. Information sharing between competent authorities is of vital importance for nuclear security. Due to the variety of responsibilities, Technical, Scientific and Operational support needs to be defined. The Member States should consider developing joint protocols on data structures and data handling to ease the information flow and so the response time.JRC.E.2-Technology Innovation in Securit
List-mode data acquisition based on digital electronics - State-of-the-art report
This report deals with digital radiation detection systems employing list-mode data collection, which improves data analysis capabilities. Future data acquisition systems shall also ultimately enable the movement of detection data from first responders electronically to analysis centres rather than the costly and time consuming process of moving experts and/or samples. This new technology is especially useful in crisis events, when time and resources are sparse and increased analysis capacity is required. In order to utilise the opportunities opened by these new technologies, the systems have to be interoperable, so that the data from each type of detector can easily be analysed by different analysis centres. Successful interoperability of the systems requires that European and/or international standards are devised for the digitised data format. The basis of such a format is a list of registered events detailing an estimate of the energy of the detected radiation, along with an accurate time-stamp for recorded events (and optionally other parameters describing each event).JRC.G.5-Security technology assessmen
Positron-neutrino correlations in 32Ar and 33Ar Decays: Probes of Scalar weak currents and nuclear isospin mixing
The positron-neutrino correlation in the 0^+ \to 0^+ \beta decay of ^{32}Ar
was measured at ISOLDE by analyzing the effect of lepton recoil on the shape of
the narrow proton group following the superallowed decay. Our result is
consistent with the Standard Model prediction; for vanishing Fierz interference
we find a=0.9989 \pm 0.0052 \pm 0.0036. Our result leads to improved
constraints on scalar weak interactions. The positron-neutrino correlation in
^{33}Ar decay was measured in the same experiment; for vanishing Fierz
interference we find a=0.944 \pm 0.002 \pm 0.003. The ^{32}Ar and ^{33}Ar
correlations, in combination with precision measurements of the half-lives,
superallowed branching ratios and beta endpoint energies, will determine the
isospin impurities of the superallowed transitions. These will provide useful
tests of isospin-violation corrections used in deducing |V_{\rm ud}| which
currently indicates non-unitarity of the KM matrix.Comment: 15 pages, 6 figure
Two-pion production in deuteron-deuteron collisions at low energies
The cross section for the dd -> 4He pi pi reaction is estimated near
threshold in a two-step model where a pion created in a first interaction
produces a second pion in a subsequent interaction. This approach, which
describes well the rates of 2pi and eta production in the pd -> 3He pi pi and
dd -> 4He eta reactions, leads to predictions that are much too low compared to
experiment. Alternatives to this and the double-Delta model will have to be
sought to explain these data.Comment: 5 pages with 4 postscript figure
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