880 research outputs found
New Physics at the International Facility for Antiproton and Ion Research (FAIR) Next to GSI
The project of the international Facility for Antiproton and Ion Research
(FAIR), co-located to the GSI facility in Darmstadt, has been officially
started on November 7, 2007. The current plans of the facility and the planned
research program will be described. An investment of about 1 billion euro will
permit new physics programs in the areas of low and medium energy antiproton
research, heavy ion physics complementary to LHC, as well as in nuclear
structure and astrophysics. The facility will comprise about a dozen
accelerators and storage rings, which will enable simultaneous operations of up
to four different beams.Comment: 7 pages, 1 figure. Invited Talk presented at the "Fourth
International Conference on Fission and Properties of Neutron-Rich nuclei",
held at Sanibel Island, Florida, November 11-17, 200
Determination of the reaction plane in ultrarelativistic nuclear collisions
In the particles produced in a nuclear collision undergo collective flow, the
reaction plane can in principle be determined through a global event analysis.
We show here that collective flow can be identified by evaluating the reaction
plane independently in two separate rapidity intervals, and studying the
correlation between the two results. We give an analytical expression for the
correlation function between the two planes as a function of their relative
angle. We also discuss how this correlation function is related to the
anisotropy of the transverse momentum distribution. Email contact:
[email protected]: Saclay-T93/026 Email: [email protected]
Directed and Elliptic Flow in 158 AGeV Pb+Pb Collisions
Directed and elliptic flow of protons and positively charged pions has been
studied in the target fragmentation region using the Plastic Ball detector in
the WA98 experiment. The results exhibit a strong dependence on centrality,
rapidity, and transverse momentum.
The rapidity dependence can be described by a Gaussian distribution. The
model comparisons reveal a large discrepancy of the flow strength obtained from
the data and the simulations.Comment: 4 pages, 4 eps figures, talk at Quark Matter 99, see also
http://qgp.uni-muenster.de/WA98/qm99/flo
Azimuthal Correlations in the Target Fragmentation Region of High Energy Nuclear Collisions
Results on the target mass dependence of proton and pion pseudorapidity
distributions and of their azimuthal correlations in the target rapidity range
are presented. The data have been taken with the
Plastic-Ball detector set-up for 4.9 GeV p + Au collisions at the Berkeley
BEVALAC and for 200 GeV/ p-, O-, and S-induced reactions on
different nuclei at the CERN-SPS. The yield of protons at backward rapidities
is found to be proportional to the target mass. Although protons show a typical
``back-to-back'' correlations, a ``side-by-side'' correlation is observed for
positive pions, which increases both with target mass and with impact parameter
of a collision. The data can consistently be described by assuming strong
rescattering phenomena including pion absorption effects in the entire excited
target nucleus.Comment: 7 pages, figures included, complete postscript available at
ftp://qgp.uni-muenster.de/pub/paper/azi-correlations.ps submitted to Phys.
Lett.
Heavy Ion Physics at RHIC
The status of the physics of heavy ion collisions is reviewed based on
measurements over the past 6 years from the Relativistic Heavy Ion Collider
(RHIC) at Brookhaven National Laboratory. The dense nuclear matter produced in
Au+Au collisions with nucleon-nucleon c.m. energy GeV at
RHIC corresponds roughly to the density and temperature of the universe a few
microseconds after the `big-bang' and has been described as "a perfect liquid"
of quarks and gluons, rather than the gas of free quarks and gluons, ``the
quark-gluon plasma" as originally envisaged. The measurements and arguments
leading to this description will be presented.Comment: 31 pages, 23 figures, Proceedings of Symposium "50+ Years of High
Energy Physics at UB", University at Buffalo, NY, October 20-21,200
Proton stopping in C+C, d+C, C+Ta and d+Ta collisions at 4.2A GeV/c
The shape of proton rapidity distributions is analysed in terms of their
Gaussian components, and the average rapidity loss is determined in order to
estimate the amount of stopping in C+C, d+C, C+Ta and d+Ta collisions at 4.2A
GeV/c. Three Gaussians correspond to the nuclear transparency and describe well
all peripheral and also C+C central collisions. Two-component shape is obtained
in case of d+C and C+Ta central collisions. Finally one Gaussian, found in d+Ta
central collisions, corresponds to the full stopping. The calculated values of
the average rapidity loss support the qualitative relationship between the
number of Gaussian components and the corresponding stopping power. It is also
observed, in central collisions, that the average rapidity loss increases with
the ratio of the number of target and the number of projectile participants.Comment: 9 pages REVTeX, 1 PS figure replaced, to be published in Phys.Rev.
Recommended from our members
Summary Of The Physics Review Panel On Heavy Ion Collider Specifications
Psychopathologie des Ganser-Syndroms: Literaturübersicht und Falldiskussion
Zusammenfassung: Das Kernsymptom des Ganser-Syndroms besteht im "Vorbeiantworten" auf einfache Fragen. Die Ursache dieses seltenen Syndroms ist unklar. Aktuelle Klassifikationssysteme zählen es zu den dissoziativen Störungen, wobei eine psychogene Ursache der Symptome angenommen wird. Anhand einer Literaturrecherche (n=151) wird jedoch gezeigt, dass das Ganser-Syndrom sehr häufig mit Hirnverletzungen assoziiert ist, wobei detaillierte bildgebende, neuropsychologische und neurologische Untersuchungen weitgehend fehlen. Wir stellen eine rechtshändige Patientin mit einem Ganser-Syndrom nach einem großen linkshemisphärischen Mediainfarkt vor. Die detaillierte neuropsychologische Untersuchung zeigte eine untypische Lateralisierung kognitiver Funktionen mit einer sog. gekreuzten Nichtaphasie und ausgeprägten frontal-exekutiven Funktionsstörungen. Unter Berücksichtigung sowohl der psychiatrischen als auch der neuropsychologischen Aspekte wird diskutiert, in welchem Zusammenhang das psychopathologische Symptom des "Vorbeiantwortens" mit spezifischen frontal-exekutiven Hirnfunktionsstörungen stehen könnt
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