3,621 research outputs found
The Compressed Baryonic Matter Experiment at FAIR: Progress with feasibility studies and detector developments
The Compressed Baryonic Matter (CBM) experiment is being planned at the
international research center FAIR, under realization next to the GSI
laboratory in Darmstadt, Germany. Its physics programme addresses the QCD phase
diagram in the region of highest net baryon densities. Of particular interest
are the expected first order phase transition from partonic to hadronic matter,
ending in a critical point, and modifications of hadron properties in the dense
medium as a signal of chiral symmetry restoration. Laid out as a fixed-target
experiment at the heavy-ion synchrotrons SIS-100/300, the detector will record
both proton-nucleus and nucleus-nucleus collisions at beam energies between 10
and 45 GeV. Hadronic, leptonic and photonic observables have to be measured
with large acceptance. The interaction rates will reach 10 MHz to measure
extremely rare probes like charm near threshold. Two versions of the experiment
are being studied, optimized for either electron-hadron or muon identification,
combined with silicon detector based charged-particle tracking and micro-vertex
detection. The CBM physics requires the development of novel detector sytems,
trigger and data acquisition concepts as well as innovative real-time
reconstruction techniques. Progress with feasibility studies of the CBM
experiment and the development of its detector systems are reported.Comment: 4 pages, 3 figures - FINAL - To appear in the conference proceedings
for Quark Matter 2009, March 30 - April 4, Knoxville, Tennesse
System size dependence of strangeness production at 158 AGeV
Strange particle production in A+A interactions at 158 AGeV is studied by the CERN experiment NA49 as a function of system size and collision geometry. Yields of charged kaons, phi and Lambda are measured and compared to those of pions in central C+C, Si+Si and centrality-selected Pb+Pb reactions. An overall increase of relative strangeness production with the size of the system is observed which does not scale with the number of participants. Arguing that rescattering of secondaries plays a minor role in small systems the observed strangeness enhancement can be related to the space-time density of the primary nucleon-nucleon collisions
Bringing BCI into everyday life: Motor imagery in a pseudo realistic environment
Bringing Brain-Computer Interfaces (BCIs) into everyday life is a challenge because an out-of-lab environment implies the presence of variables that are largely beyond control of the user and the software application. This can severely corrupt signal quality as well as reliability of BCI control. Current BCI technology may fail in this application scenario because of the large amounts of noise, nonstationarity and movement artifacts. In this paper, we systematically investigate the performance of motor imagery BCI in a pseudo realistic environment. In our study 16 participants were asked to perform motor imagery tasks while dealing with different types of distractions such as vibratory stimulations or listening tasks. Our experiments demonstrate that standard BCI procedures are not robust to theses additional sources of noise, implicating that methods which work well in a lab environment, may perform poorly in realistic application scenarios. We discuss several promising research directions to tackle this important problem.BMBF, 01GQ1115, Adaptive Gehirn-Computer-Schnittstellen (BCI) in nichtstationären Umgebunge
System-size dependence of strangeness production in high-energy A+A collisions and percolation of strings
We argue that the shape of the system-size dependence of strangeness production in nucleus-nucleus collisions can be understood in a picture that is based on the formation of clusters of overlapping strings. A string percolation model combined with a statistical description of the hadronization yields a quantitative agreement with the data at sqrt s_NN = 17.3 GeV. The model is also applied to RHIC energies
Fayet-Iliopoulos Terms in AdS/CFT with Flavour
We construct the gravity dual of a field theory with flavour in which there
are Fayet-Iliopoulos (FI) terms present. For this purpose we turn on a constant
Kalb-Ramond B field in four internal space directions of AdS_5 x S^5 together
with a D7 brane probe wrapping AdS_5 x S^3. The B field induces
noncommutativity on the four internal directions of the D7 brane probe
perpendicular to the AdS boundary. We argue on general grounds that the moduli
space of the Higgs part of mixed Coulomb-Higgs states in the dual field theory
at the boundary is described by the ADHM equations for noncommutative
instantons on the four internal directions of the D7 brane probe. In
particular, the global symmetries match. The FI term arises as the holographic
dual of an anti-selfdual B field. We discuss possible applications for this
construction.Comment: 31 pages, 2 figures, JHEP 3 style, v2: References added, final
published versio
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