1,474 research outputs found
Distributions of secondary muons at sea level from cosmic gamma rays below 10 TeV
The FLUKA Monte Carlo program is used to predict the distributions of the
muons which originate from primary cosmic gamma rays and reach sea level. The
main result is the angular distribution of muons produced by vertical gamma
rays which is necessary to predict the inherent angular resolution of any
instrument utilizing muons to infer properties of gamma ray primaries.
Furthermore, various physical effects are discussed which affect these
distributions in differing proportions.Comment: 36 pages, 13 figures, minor revision, new layou
d-Au and p-p collisions at RHIC and the multichain Monte Carlo Dpmjet-III
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
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
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
The Io sulfur torus in 1981
A Fabry-Perot spectrometer was used to obtain images of the Io torus in emission lines of S II (wavelength 6716 and 6731) and S III (wavelength 9531) in February and March 1981, on the 2.1 meter telescope at KPNO. The S II and S III images showed a large variation in brightness and radial extent. There is an indication the S II and S III emissions in the warm torus are correlated. The S II and S III emissions in the warm torus also have similar scale heights along the magnetic field lines of approximately 0.6 to 0.72 R sub J. The east-west asymmetry in the S II images taken at similar magnetic longitudes, but 2.5 Jovian rotations apart, supports the theory of convective motions suggested by others. In addition to the images, simultaneous measurements of the S II (6731 wavelength) line profile were also made on one night using a Fabry-Perot scanning spectrometer on the 4 meter at KPNO. The S II spectral scans implied ion temperatures of 52 (+ or - 10) x 10 to the 3rd at 5.2 to 5.6 R sub J from Jupiter and a minimum temperature of at least 3 x 10 to the 5th K at 6 R sub J from Jupiter
Fabry-Perot observations of comet Kohoutek
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
Low intensity H-beta emission from the interstellar medium
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
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