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Transverse mass and rapidity distributions for charged pions, charged kaons, protons, and antiprotons are reported for sqrt[sNN]=200 GeV pp and Au+Au collisions at Relativistic Heary Ion Collider (RHIC). Chemical and kinetic equilibrium model fits to our data reveal strong radial flow and long duration from chemical to kinetic freeze-out in central Au+Au collisions. The chemical freeze-out temperature appears to be independent of initial conditions at RHIC energies.
Measurements of the production of forward high-energy pi 0 mesons from transversely polarized proton collisions at sqrt[s]=200 GeV are reported. The cross section is generally consistent with next-to-leading order perturbative QCD calculations. The analyzing power is small at xF below about 0.3, and becomes positive and large at higher xF, similar to the trend in data at sqrt[s] <= 20 GeV. The analyzing power is in qualitative agreement with perturbative QCD model expectations. This is the first significant spin result seen for particles produced with pT>1 GeV/c at a polarized proton collider.
We report results on rho (770)0--> pi + pi - production at midrapidity in p+p and peripheral Au+Au collisions at sqrt[sNN]=200 GeV. This is the first direct measurement of rho (770)0--> pi + pi - in heavy-ion collisions. The measured rho 0 peak in the invariant mass distribution is shifted by ~40 MeV/c2 in minimum bias p+p interactions and ~70 MeV/c2 in peripheral Au+Au collisions. The rho 0 mass shift is dependent on transverse momentum and multiplicity. The modification of the rho 0 meson mass, width, and shape due to phase space and dynamical effects are discussed.
We report the first observations of the first harmonic (directed flow, v1) and the fourth harmonic (v4), in the azimuthal distribution of particles with respect to the reaction plane in Au+Au collisions at the BNL Relativistic Heavy Ion Collider (RHIC). Both measurements were done taking advantage of the large elliptic flow (v2) generated at RHIC. From the correlation of v2 with v1 it is determined that v2 is positive, or in-plane. The integrated v4 is about a factor of 10 smaller than v2. For the sixth (v6) and eighth (v8) harmonics upper limits on the magnitudes are reported.
Azimuthally sensitive Hanbury Brown-Twiss interferometry in Au+Au collisions at sqrt[sNN]=200 GeV
(2004)
We present the results of a systematic study of the shape of the pion distribution in coordinate space at freeze-out in Au+Au collisions at BNL RHIC using two-pion Hanbury Brown-Twiss (HBT) interferometry. Oscillations of the extracted HBT radii versus emission angle indicate sources elongated perpendicular to the reaction plane. The results indicate that the pressure and expansion time of the collision system are not sufficient to completely quench its initial shape.
Studien zur Lokalisation: Teil: 2.: Verbgebundene Lokalisation vs. Lokalisation von Propositionen
(1992)
Der vorliegende Aufsatz gliedert sich in zwei Unterabschnitte. In Abschnitt I geht es um verbgebundene, von der Valenz geforderte Lokalisation. Die einzelsprachlichen Beispiele zeigen, daß es sich konstant um Verben der Position oder Positionsveränderung (Bewegungs - und Transferverben) handelt, die lokale Relationen wie LOK (Ortsruhe), SOURCE oder GOAL fordern. Unter Bezugnahme auf die Erkenntnisse zur Dimension der PARTIZIPATION (H. Seiler/W. Premper 1991) können die Varianten, wie sie in der einzelsprachlichen Kodierung zu beobachten sind, zwischen den Polen zentralisiert und dezentralisiert (peripher) angeordnet werden . Dies bedeutet, daß lokale Relationen (als verbgebundene Entitäten) einerseits am Partizipatum selbst und andererseits im Bereich der Partizipanten in Gestalt verschiedener grammatischer Relationen in Erscheinung treten können. Im ersteren Fall kann die Inkorporation einer lokalen Ergänzung ins Partizipatum als optimal zentralisiert betrachtet werden, während eine Kodierung als Präpositionalphrase das andere Extrem darstellt. Dazwischen liegt eine Kodierung als "Subjekt"- bzw. "Objekt"-Relation, für die sich, wie auch für die anderen Fälle, eine Reihe von Beispielen finden lassen. Somit schwankt die Skala der Kodierungsmöglichkeiten für verbgebundene lokale Relationen zwischen Inkorporation und Präpositional-/Postpositionalphrasen, was letztlich eine Differenzierung in markierte und unmarkierte, im letzteren Falle gar prototypische Instanzen bedeutet. Im II . Abschnitt geht es darum, so weit dies möglich erscheint, Varianten zu beschreiben, die funktional die Aufgabe einer Situierung einer Gesamtproposition bewerkstelligen.
Two-pion correlation functions in Au+Au collisions at sqrt[sNN] = 130 GeV have been measured by the STAR (solenoidal tracker at RHIC) detector. The source size extracted by fitting the correlations grows with event multiplicity and decreases with transverse momentum. Anomalously large sizes or emission durations, which have been suggested as signals of quark-gluon plasma formation and rehadronization, are not observed. The Hanbury Brown-Twiss parameters display a weak energy dependence over a broad range in sqrt[sNN].
The first measurements of light antinucleus production in Au+Au collisions at the Relativistic Heavy-Ion Collider are reported. The observed production rates for d-bar and 3He-bar are much larger than in lower energy nucleus-nucleus collisions. A coalescence model analysis of the yields indicates that there is little or no increase in the antinucleon freeze-out volume compared to collisions at CERN SPS energy. These analyses also indicate that the 3He-bar freeze-out volume is smaller than the d-bar freeze-out volume.
We present the first measurement of midrapidity vector meson phi production in Au+Au collisions at RHIC (sqrt[sNN]=130 GeV) from the STAR detector. For the 11% highest multiplicity collisions, the slope parameter from an exponential fit to the transverse mass distribution is T=379±50(stat)±45(syst) MeV, the yield dN/dy=5.73±0.37(stat)±0.69(syst) per event, and the ratio N phi /Nh- is found to be 0.021±0.001(stat)±0.004(syst). The measured ratio N phi /Nh- and T for the phi meson at midrapidity do not change for the selected multiplicity bins.