All of the former transition economies
in Central, Eastern, and Southern Europe (CESE) inherited
from the era of central planning traditional defined-benefit
pension systems financed on a ...pay-as-you-go basis. Like many
pay-as-you-go public pension systems elsewhere in the world,
CESE pension systems were in need of reforms to address
short-term fiscal imbalances and longer-term issues relating
to population aging. Reforms were also needed to adjust
benefit and contribution structures to meet the challenges
of-as well as to take advantage of opportunities relating to
the transition to a market economy, including the widespread
adoption of multiplier designs with improved risk-sharing
across funded and unfunded pillars. By 2006, most countries
in Europe and Central Asia had introduced a voluntary
private pension scheme. By 2008, 14 countries roughly half
of all countries in the region had legislated mandatory
private pension schemes, and all but one of those schemes
(the one in Ukraine) had been introduced. These reforms
shared a number of common objectives, in particular putting
the systems on a sounder financial footing and better
aligning them with the (very different) incentives of a
market economy. This report is organized as follows. The
first section discusses the motivation for reform across the
eight countries included in the study against the backdrop
of the regional (and global) trend toward multiplier pension
arrangements. The second section summarizes the key
provisions of the reformed systems in the eight countries
within the World Bank's five-pillar framework for
pension system design. The third section summarizes pension
system performance against the two crucially important
dimensions of adequacy and sustainability. The last section
provides some policy recommendations for addressing gaps in
reforms and taking advantage of further opportunities.
We present data on dielectron emission in proton induced reactions on a Nb target at 3.5 GeV kinetic beam energy measured with HADES installed at GSI. The data represent the first high statistics ...measurement of proton-induced dielectron radiation from cold nuclear matter in a kinematic regime, where strong medium effects are expected. Combined with the good mass resolution of 2%, it is the first measurement sensitive to changes of the spectral functions of vector mesons, as predicted by models for hadrons at rest or small relative momenta. Comparing the e+e− invariant mass spectra to elementary p+p data, we observe for e+e− momenta Pee<0.8 GeV/c a strong modification of the shape of the spectrum, which we attribute to an additional ρ-like contribution and a decrease of ω yield. These opposite trends are tentatively interpreted as a strong coupling of the ρ meson to baryonic resonances and an absorption of the ω meson, which are two aspects of in-medium modification of vector mesons.
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The combination of a production target for secondary beams, an optimized ion optical beam line setting, in-beam detectors for minimum ionizing particles with high rate capability, and an efficient ...large acceptance spectrometer around the reaction target constitutes an experimental opportunity to study in detail hadronic interactions utilizing pion beams impinging on nucleons and nuclei. For the 0.4-2.0GeV/c pion momentum regime such a facility is located at the heavy ion synchrotron accelerator SIS18 in Darmstadt (Germany). The layout of the apparatus, performance of its components and encouraging results from a first commissioning run are presented.
The tagged quasi-free np→npπ+π− reaction has been studied experimentally with the High Acceptance Di-Electron Spectrometer (HADES) at GSI at a deuteron incident beam energy of 1.25 GeV/nucleon ...(s∼2.42 GeV/c for the quasi-free collision). For the first time, differential distributions of solid statistics for π+π− production in np collisions have been collected in the region corresponding to the large transverse momenta of the secondary particles. The invariant mass and angular distributions for the np→npπ+π− reaction are compared with different models. This comparison confirms the dominance of the t-channel with ΔΔ contribution. It also validates the changes previously introduced in the Valencia model to describe two-pion production data in other isospin channels, although some deviations are observed, especially for the π+π− invariant mass spectrum. The extracted total cross section is also in much better agreement with this model. Our new measurement puts useful constraints for the existence of the conjectured dibaryon resonance at mass M∼2.38 GeV and with width Γ∼70 MeV.
The alignment strategy of HADES Pechenova, O.; Pechenov, V.; Galatyuk, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2015, Letnik:
785
Journal Article
Recenzirano
The global as well as intrinsic alignment of any spectrometer impacts directly on its performance and the quality of the achievable physics results. An overview of the current alignment procedure of ...the DiElectron Spectrometer HADES is presented with an emphasis on its main features and its accuracy. The sequence of all steps and procedures is given, including details on photogrammetric and track-based alignment.
We present first data on sub-threshold production of Ks0 mesons and Λ hyperons in Au+Au collisions at sNN=2.4 GeV. We observe an universal 〈Apart〉 scaling of hadrons containing strangeness, ...independent of their corresponding production thresholds. Comparing the yields, their 〈Apart〉 scaling, and the shapes of the rapidity and the pt spectra to state-of-the-art transport model (UrQMD, HSD, IQMD) predictions, we find that none of them can simultaneously describe these observables with reasonable χ2 values.
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