764 research outputs found

    d-Au and p-p collisions at RHIC and the multichain Monte Carlo Dpmjet-III

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    In this paper we compare systematically the two-component Dual Parton Model (DPM) event generator Dpmjet-III to d-Au and p-p data from RHIC. In this process we are able to improve the model. The need for fusion of chains and a recalibration of the model to obtain collision scaling in h-A and d-A collisions was found already in previous comparisons. Here, comparing to transverse momentum distributions of identified charged hadrons we find also the need to modify the transverse momentum distributions in the decay of hadronic strings, the basic building blocks of the model on soft hadronic collisions.Comment: 8 pages, 13 figures, Based on a contribution to a workshop "QCD at Cosmic Energies, Erice, Italie, Aug.29 to Sept.5 200

    Antibaryon to Baryon Production Ratios in Pb-Pb and p-p collision at LHC energies of the DPMJET-III Monte Carlo

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    A sizable component of stopped baryons is predicted for pp and P bP b collisions at LHC. Based on an analysis of RHIC data within framework of our multichain Monte Carlo DPMJET-III the LHC predictions are presented.Comment: Presented at "Heavy Ion Collisions at the LHC: last call for predictions", Geneva Switzerland, May 14th-June 8t

    RHIC data and the multichain Monte Carlo DPMJET-II

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    Using data from RHIC we are able to systematically improve the two-component Dual Parton Model (DPM) event generator DPMJET-III. Introducing percolation parametrized as fusion of chains the model describes multiplicities and pseudorapidity distributions in nucleus-nucleus collisions at all centralities. Guided by the d-Au data from RHIC we recalibrate the model to obtain collision scaling in h-A and d-A collisions.Comment: 8 pages, Based on a poster submitted to the 17th International Conference on Ultra Relativistic Nucleus Nucleus Collisions, Jan. 11-17, Oakland,California US

    Low intensity H-beta emission from the interstellar medium

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    A search for diffuse galactic H beta emission not associated with any known H II regions was conducted using a 2-inch-diamenter pressure-scanned Fabry-Perot spectrometer at the Coude focus of a 36-inch telescope. Observations were made near the directions of four pulsars. Emissions with intensities from 40,000 to 400,000 photons/sq cm sec ster (corresponding to emission measures of approximately 10 - 100) were detected in three of the directions. The data indicate an average ionization rate (assuming steady state) of approximately 10 to the minus 14th power/H-atom sec for the interstellar hydrogen in these directions and temperatures between 1000 and 10,000 K for the emitting regions. Plans were made to continue the investigation of these very faint hydrogen emission sources using a 6-inch-diameter Fabry-Perot spectrometer

    Fabry-Perot observations of comet Kohoutek

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    Observations of H alpha, H20(+), and emission lines from comet Kohoutek were made. Analyses of H alpha line profiles and line intensities indicate that the mean outflow velocity of the hydrogen atoms was 7.8 + or - 0.2 km s(-1) and that the hydrogen atom production rate varied for comet-sun distances between 1 AU and 0.4 AU. The identification of an H20(+) emission feature in certain H alpha scans indicates that the H20(+) ions were moving in a tailward direction with a velocity of 20 to 40 km s(-1) with respect to the comet nucleus. An upper limit of 1 part in 100 was found for the D/H ratio in the cometary atomic hydrogen cloud

    A study of the Jovian [S II] nebula at high spectral resolution

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    Observations of forbidden line S II λλ6716-6731 A emissions from the Jovian magnetosphere have been carried out with a PEPSIOS spectrometer at the Hale 5 m telescope. Spectral resolving power was sufficient to resolve the forbidden line S II line widths. From measured λλ6716-6731 A doublet ratios and spectral line widths a thermal plasma is found characterized by temperatures about 2 x 10^4 K and electron densities about ~2 x 10^3 cm^(-3). The source of forbidden line S II emissions was centered within a toroidal region of radius 5 Jupiter radii (inside the orbit of Io), with tight latitudinal confinement near the equilibrium equator for ions in the tilted corotating Jovian magnetic field, and significant long-lived longitudinal structure

    Omjer tvorbe antibariona i bariona u sudarima Pb-Pb i p-p na energijama LHC programom DPMJET-III Monte Carlo

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    A sizable component of stopped baryons is predicted for pp and PbPb collisions at LHC. Based on an analysis of RHIC data within framework of our multi-chain Monte Carlo DPMJET-III the LHC predictions for pp and PbPb are presented.Predviđamo poveću komponentu zaustavljenih bariona u pp i PbPb u LHC mjerenjima. Predstavljamo LHC predviđanja za pp i PbPb sudare dana nasim više-niznim Monte Carlo DPMJET-III simulacijama zasnovanim na analizama RHIC podataka

    Omjer tvorbe antibariona i bariona u sudarima Pb-Pb i p-p na energijama LHC programom DPMJET-III Monte Carlo

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    A sizable component of stopped baryons is predicted for pp and PbPb collisions at LHC. Based on an analysis of RHIC data within framework of our multi-chain Monte Carlo DPMJET-III the LHC predictions for pp and PbPb are presented.Predviđamo poveću komponentu zaustavljenih bariona u pp i PbPb u LHC mjerenjima. Predstavljamo LHC predviđanja za pp i PbPb sudare dana nasim više-niznim Monte Carlo DPMJET-III simulacijama zasnovanim na analizama RHIC podataka

    Data-Model Comparison Search Analysis of Coincident PBO Balmer α, EURD Lyman β Geocoronal Measurements From March 2000

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    Recent Lyman series and Balmer series airglow measurements provide a fresh opportunity to investigate the density distribution and variability of atomic hydrogen in the upper atmosphere. Dedicated nightside Balmer α Fabry-Perot spectrometer measurements at the Pine Bluff Observatory (PBO), University of Wisconsin-Madison, have been acquired since late 1999 taking advantage of several technological advances. Extreme ultraviolet spectral radiance measurements by the Espectrógrafo Ultravioleta extremo para la Radiación Difusa (EURD) instrument on the Spanish MINISAT-1 satellite from October 1997 to December 2001 provide extensive sets of geocoronal Lyman β, Lyman γ and He 584 Å emission intensities. In this paper, coincident EURD Lyman β and PBO Balmer α radiance measurements from the early March 2000 new moon period are presented. In addition to serving as examples of the data sets now available, the data volume poses an analysis challenge not faced in prior geocoronal studies. A data-model comparison search procedure employing resonance radiation transport results for extensive sets of parametric density distribution models is being developed for use in analyses of multiple large data sets; this is described, and example results for the PBO and EURD March 2000 data sets are presented. The tightness of the constraints obtained for the solar line-center Lyman β irradiance and the atomic hydrogen column abundance is somewhat surprising, given the crudeness of the parameter binning in the search procedure and the fact that a small number of recognized corrections remain to be made to each data set

    Antiparticle to Particle Production Ratios in Hadron-Hadron and d-Au Collisions in the DPMJET-III Monte Carlo

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    To understand baryon stopping we analyse new RHIC and Fermilab data within the framework of the multichain Monte Carlo DPMJET-III. The present consideration is restricted to to hadron-hadron and d-Au collisions.Comment: 10 pages, 19 figures. The paper is expanded in a mayor way to include more dat
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