419 research outputs found

    Transcript of The Dory Derby Accident

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    This story is an excerpt from a longer interview that was collected as part of the Launching through the Surf: The Dory Fleet of Pacific City project. In this story, Don Grotjohn recounts an accident that occurred during a Dory Derby competition

    Centrality dependence of the expansion dynamics in Pb-Pb collisions at 158 A GeV/c

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    Two-particle correlation functions of negatively charged hadrons from Pb-Pb collisions at 158 GeV/c per nucleon have been measured by the WA97 experiment at the CERN SPS. A Coulomb correction procedure that assumes an expanding source has been implemented. Within the framework of an expanding thermalized source model the size and dynamical state of the collision fireball at freeze-out have been reconstructed as a function of the centrality of the collision. Less central collisions exhibit a different dynamics than central ones: both transverse and longitudinal expansion velocities are slower, the expansion duration is shorter and the system freezes out showing smaller dimensions and higher temperature.Comment: 22 pages, 11 figures, Te

    Rapidity distributions around mid-rapidity of strange particles in Pb-Pb collisions at 158 AA GeV/c

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    The production at central rapidity of K0s, Lambda, Xi and Omega particles in Pb-Pb collisions at 158 A GeV/c has been measured by the NA57 experiment over a centrality range corresponding to the most central 53% of the inelastic Pb-Pb cross section. In this paper we present the rapidity distribution of each particle in the central rapidity unit as a function of the event centrality. The distributions are analyzed based on hydrodynamical models of the collisions.Comment: 15 pages, 10 figure

    Study of the transverse mass spectra of strange particles in Pb-Pb collisions at 158 A GeV/c

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    The NA57 experiment has collected high statistics, high purity samples of \PKzS and \PgL, Ξ\Xi and Ω\Omega hyperons produced in Pb-Pb collisions at 158 AA GeV/cc. In this paper we present a study of the transverse mass spectra of these particles for a sample of events corresponding to the most central 53% of the inelastic Pb-Pb cross-section. We analyse the transverse mass distributions in the framework of the blast-wave model for the full sample and, for the first time at the SPS, as a function of the event centrality.Comment: 22 pages, 14 figures, submitted to J. Phys. G: Nucl. Phy

    Transverse mass spectra of strange and multi-strange particles in Pb-Pb collisions at 158 A GeV/c

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    The WA97 experiment has measured the transverse mass (\mT) spectra fornegative hadrons (\hneg) and strange particles produced at mid--rapidity in Pb--Pb collisions. The increased statistics of analysed data samples allowed us to perform a study of the spectra of \PKzS, \PgL, Ξ\mathrm{\Xi}, Ω\mathrm{\Omega} and\hneg~as a function of the collision centrality. The data, whichcorrespond to the most central 40\% of the total inelastic cross section,have been divided into four centrality classes according to the estimated numberof nucleons taking part in the collision. The \mT~ spectra, analysed separatelyfor each centrality bin, exhibit only weak (≤\leq 15\%) centrality dependence. The deviation of theΩ\mathrm{\Omega} inverse slope from the linear dependence on the particle massis confirmed even for the most central Pb--Pb collisions

    Hyperon production in proton-sulphur collisions at 200 GeV/c

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    The WA94 experiment uses the production of strange particles and antiparticles to investigate the properties of hot hadronic matter created in heavy--ion interactions. \PgL, \PagL, \PgXm\ and \PagXp\ particle yields and transverse mass spectra are presented for pS interactions. These results are compared with those from SS interactions. Our results are also compared with those from pW and SW interactions of the WA85 experiment

    Determination of the number of wounded nucleons in Pb+Pb collisions at 158 A GeV/c

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    The charged particle multiplicity distributions measured by two experiments, WA97 and NA57, in Pb+Pb collisions at 158 A GeV/c have been analyzed in the framework of the wounded nucleon model (WNM). We obtain a good description of the data within the centrality range of our samples. This allows us to make use of the measured multiplicities to estimate the number of wounded nucleons of the collision
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