24,811 research outputs found
Primakoff Physics for CERN COMPASS Hadron Beam: Hadron Polarizabilities, Hybrid Mesons, Chiral Anomaly, Meson Radiative Transitions
We describe a hadron physics program attainable with a partially instrumented
CERN COMPASS spectrometer, involving tracking detectors and moderate-size
ECAL2/HCAL2 calorimeters. COMPASS can realize a state-of-the-art hadron beam
physics program based on hadron polarizability, hybrid mesons, chiral anomaly,
and meson radiative transition studies. We review here the physics motivation
for this hadron beam program. We describe the beam, detector, trigger
requirements, and hardware/software requirements for this program. The triggers
for all this physics can be implemented for simultaneous data taking. The
program is based on using a hadron beam (positive/negative pion, kaon, proton)
in COMPASS.Comment: Contribution to the Proceedings of the Charles U./JINR and
International U. (Dubna) CERN COMPASS Summer School, Charles University,
Prague, Czech Republic, August 1997, Eds. M. Chavleishvili and M. Finger Tel
Aviv U. Preprint TAUP TAUP-2473-98. 26 pages, 11 figures, late
Mode fluctuations as fingerprint of chaotic and non-chaotic systems
The mode-fluctuation distribution is studied for chaotic as well as
for non-chaotic quantum billiards. This statistic is discussed in the broader
framework of the functions being the probability of finding energy
levels in a randomly chosen interval of length , and the distribution of
, where is the number of levels in such an interval, and their
cumulants . It is demonstrated that the cumulants provide a possible
measure for the distinction between chaotic and non-chaotic systems. The
vanishing of the normalized cumulants , , implies a Gaussian
behaviour of , which is realized in the case of chaotic systems, whereas
non-chaotic systems display non-vanishing values for these cumulants leading to
a non-Gaussian behaviour of . For some integrable systems there exist
rigorous proofs of the non-Gaussian behaviour which are also discussed. Our
numerical results and the rigorous results for integrable systems suggest that
a clear fingerprint of chaotic systems is provided by a Gaussian distribution
of the mode-fluctuation distribution .Comment: 44 pages, Postscript. The figures are included in low resolution
only. A full version is available at
http://www.physik.uni-ulm.de/theo/qc/baecker.htm
Hadron-Photon Interactions in COMPASS
The COMPASS experiment at CERN SPS will use hadron beams (pion, kaon and
proton) and muons at 50-280 GeV/c and virtual photon targets to investigate,
via Primakoff effect, important hadron properties: polarizability, chiral
anomaly, radiative transitions and hybrid meson production. We present
simulation studies to optimize the beam, detector setup and trigger for
measuring with high statistics above topics.Comment: 10 pages, 3 figures, 3 macro
Public works for Poland? Active labour market policies during transition
Following the predominance of macroeconomic stabilisation policies and passive income support schemes in the first phase of transition, active labour market policies (ALMPs) have now come to play a more important role in transition economies. This paper looks at the Polish experience and provides empirical evidence on the effectiveness of ALMPs. We use the Polish Labour Force Survey of August 1994 in combination with its Supplement on the Evaluation of Labour Market Policies together with data on ALMP expenditure at the regional (voivodship) level. The macroeconometric analysis of the relationship between labour market flows and ALMP expenditure shows no significant effects. The microeconometric analysis reveals that ALMPs are not particularly well targeted at the problem groups in the labour market. That is, women and people with basic vocational education do not receive enough attention, whereas persons formerly employed in the public administration seem to have a privileged status in ALMPs. As to the effectiveness of ALMPs, the paper shows that former participants cannot expect to find employment more easily than their peers who have been unemployed but have not been in a programme. Subjective evaluations of former participants also suggest that ALMPs, but especially works programmes, have not increased their chances to find a job. --unemployment,active labour market policies,Poland
Transient jets in V617 Sagittarii
Some of the luminous Compact Binary Supersoft X-Ray sources (CBSS) have shown
indications of jets, also called satellites due to their appearance in the
spectra. In V Sagittae (V Sge) stars, the galactic counterparts of the CBSS,
such features have been reported only for WX Cen. If V Sge stars are indeed the
analogs of CBSS, one may expect transient jet emission in other objects of this
class. Spectroscopic observations of the V Sge star V617 Sgr have been made,
both at high photometric state and at decline. We show that V617 Sgr presents
Halpha satellites at high photometric state with velocities of +/-780 km/s.
This feature confirms, once more, the CBSS nature of the V Sge stars, however
the details of the spectral characteristics also suggest that the two groups of
stars display some intrinsic spectroscopic differences, which are likely to be
due to a selection effect related to chemical abundance.Comment: Four pages, accepted to be published as a Letter in A&
Dynamic scaling and universality in evolution of fluctuating random networks
We found that models of evolving random networks exhibit dynamic scaling
similar to scaling of growing surfaces. It is demonstrated by numerical
simulations of two variants of the model in which nodes are added as well as
removed [Phys. Rev. Lett. 83, 5587 (1999)]. The averaged size and connectivity
of the network increase as power-laws in early times but later saturate.
Saturated values and times of saturation change with paramaters controlling the
local evolution of the network topology. Both saturated values and times of
saturation obey also power-law dependences on controlling parameters. Scaling
exponents are calculated and universal features are discussed.Comment: 7 pages, 6 figures, Europhysics Letters for
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