29 research outputs found
Antideuteron and deuteron production in mid-central Pb+Pb collisions at 158 GeV
Production of deuterons and antideuterons was studied by the NA49 experiment
in the 23.5% most central Pb+Pb collisions at the top SPS energy of
=17.3 GeV. Invariant yields for and were measured
as a function of centrality in the center-of-mass rapidity range .
Results for together with previously published
measurements are discussed in the context of the coalescence model. The
coalescence parameters were deduced as a function of transverse momentum
and collision centrality.Comment: 9 figure
System-size and centrality dependence of charged kaon and pion production in nucleus-nucleus collisions at 40A GeV and158A GeV beam energy
Measurements of charged pion and kaon production are presented in centrality
selected Pb+Pb collisions at 40A GeV and 158A GeV beam energy as well as in
semi-central C+C and Si+Si interactions at 40A GeV. Transverse mass spectra,
rapidity spectra and total yields are determined as a function of centrality.
The system-size and centrality dependence of relative strangeness production in
nucleus-nucleus collisions at 40A GeV and 158A GeV beam energy are derived from
the data presented here and published data for C+C and Si+Si collisions at 158A
GeV beam energy. At both energies a steep increase with centrality is observed
for small systems followed by a weak rise or even saturation for higher
centralities. This behavior is compared to calculations using transport models
(UrQMD and HSD), a percolation model and the core-corona approach.Comment: 32 pages, 14 figures, 4 tables, typo table II correcte
Energy Dependence of Multiplicity Fluctuations in Heavy Ion Collisions at the CERN SPS
Multiplicity fluctuations of positively, negatively and all charged hadrons
in the forward hemisphere were studied in central Pb+Pb collisions at 20A, 30A,
40A, 80A and 158A GeV. The multiplicity distributions and their scaled
variances are presented in dependence of collision energy as well as of
rapidity and transverse momentum. The distributions have bell-like shape and
their scaled variances are in the range from 0.8 to 1.2 without any significant
structure in their energy dependence. No indication of the critical point in
fluctuations are observed. The string-hadronic model UrQMD significantly
overpredicts the mean, but approximately reproduces the scaled variance of the
multiplicity distributions. The predictions of the statistical hadron-resonance
gas model obtained within the grand-canonical and canonical ensembles disagree
with the measured scaled variances. The narrower than Poissonian multiplicity
fluctuations measured in numerous cases may be explained by the impact of
conservation laws on fluctuations in relativistic systems.Comment: 26 pages, 34 figures, updated version including referee comment
Status and further Analysis Plans of the NA49 Collaboration
Status report 2008 of the NA49 collaboration to the SPS
Energy dependence of fluctuations in central Pb+Pb collisions from NA49 at the CERN SPS
The latest NA49 results on fluctuations of multiplicity and average transverse-momentum analyzed on an event-by-event basis are presented for central Pb+Pb interactions over the whole SPS energy range (20A - 158A GeV). The scaled variance of the multiplicity distribution decreases with collision energy whereas the measure of fluctuations is small and independent of collision energy. Thus in central Pb+Pb collisions these fluctuations do not show an indication of the critical point of strongly interacting matter.The latest NA49 results on fluctuations of multiplicity and average transverse-momentum analyzed on an event-by-event basis are presented for central Pb+Pb interactions over the whole SPS energy range (20A - 158A GeV). The scaled variance of the multiplicity distribution decreases with collision energy whereas the $\Phi_{p_{T}}$ measure of fluctuations is small and independent of collision energy. Thus in central Pb+Pb collisions these fluctuations do not show an indication of the critical point of strongly interacting matter
Energy dependence of Lambda and Xi production in central Pb+Pb collisions at 20A, 30A, 40A, 80A, and 158A GeV measured at the CERN Super Proton Synchrotron
Results on , \bar{\Lambda}}, , and
production in central Pb+Pb reactions at 20A, 30A, 40A, 80A, and 158A GeV are
presented. The energy dependence of transverse mass spectra, rapidity spectra,
and multiplicities is discussed. Comparisons to string hadronic models (UrQMD
and HSD) and statistical hadron gas models are shown. While the latter provide
a reasonable description of all particle yields, the first class of models
fails to match the , and multiplicities.Comment: 16 pages, 16 figures. Finally published version after editorial
revisio
Search for the QCD critical point at SPS energies
Lattice QCD calculations locate the QCD critical point at energies accessible at the CERN Super Proton Synchrotron (SPS). We present average transverse momentum and multiplicity fluctuations, as well as baryon and anti-baryon transverse mass spectra which are expected to be sensitive to effects of the critical point. The future CP search strategy of the NA61/SHINE experiment at the SPS is also discussed.Lattice QCD calculations locate the QCD critical point at energies accessible at the CERN Super Proton Synchrotron (SPS). We present average transverse momentum and multiplicity fluctuations, as well as baryon and anti-baryon transverse mass spectra which are expected to be sensitive to effects of the critical point. The future CP search strategy of the NA61/SHINE experiment at the SPS is also discussed
Swiss Competence Center on Energy Research FURIES - Overview and Contributions in the Area of Power Electronics and Smart Grids
This paper introduces a special session on results of the Swiss competence center on energy research FURIES that has been established in coordination with the Swiss Energy strategy 2050 with the specific aim to develop, promote and deploy power grid-related innovative solutions toward the im-plementation of the Swiss Energy Strategy 2050. This contribution will report on activities within WP 3, "AC/DC multi-terminal grids and power electronics". This WP includes three subtasks with contributions from the major Swiss technical universities: Multi-terminal HVDC system design, fault detection and clearing in multi-terminal HVDC, enabling component and converter technolo-gies and applications. The spectrum of the center's activities is briefly introduced and as an illustra-tive example, the contributions of the SCCER FURIES in relation with HVDC grids are summa-rized. These contributions include: new high power DC testing methods and laboratories, new DC breaker principles and fault location techniques, AC/DC grid resonance analysis and novel converter technologies