117754834
Emission of Relativistic Light Fragments in Nucleus-Emulsion Collisions at High Energy
The transverse momentum, emission angle and pseudorapidity distributions of relativistic ® fragments produced in nucleus-emulsion collisions have been analysed using a two-temperature emission picture. The two emission sources are the projectile spectator contact layer (hot spectator) with high temperature and the other part (cold spectator) with low temperature. The transverse momentum distributions of relativistic proton fragments produced in nucleus-emulsion collisions at high energy have been analysed by a three-temperature emission picture. The three emission sources are the projectile participant local region that emits the leading protons, the projectile spectator contact layer (hot spectator) and the other part (cold spectator), respectively. The calculated results are in agreement with the experimental data of nucleus-emulsion collisions in the present accelerator energy region. The temperatures of the emission sources can be obtained from one of the transverse momentum, emission angle and pseudorapidity distributions. For a heavy projectile at high energy (for example 208Pb at 160A GeV), the temperatures of the hot spectator and the cold spectator obtained from the pseudorapidity distribution of relativistic ® fragments are 120 and 40 MeV, respectively.
122076971
ANGULAR DISTRIBUTIONS OF TARGET BLACK FRAGMENTS IN NUCLEUS NUCLEUS COLLISIONS AT HIGH ENERGY
The experimental results of space, azimuthal, and projected angular distributions of target black fragments produced in silicon-emulsion collisions at 4.5A GeV/c (the Dubna energy) are reported. A multi-source ideal gas model is suggested to describe the experimental angular distributions. The Monte Carlo calculated results are in agreement with the experimental data.
118607664
Singly and Doubly Charged Projectile Fragments in Nucleus-Emulsion Collisions at Dubna Energy in the Framework of the Multi-Source Model *
The multiplicity distributions of projectile fragments emitted in interactions of different nuclei with emulsion are studied by using a multi-source model. Our calculated results show that the projectile fragments can be described by the model and each source contributes an exponential distribution. As the weighted sum of the folding result of many exponential distributions, a multi-component Erlang distribution is used to describe the experimental data. The relationship between the height (or width) of the distribution and the mass of the incident projectile, as well as the dependence of projectile fragments on target groups, are investigated too.
122540755
Particle production in Au–Au collisions at RHIC energies
Abstract An overlapping cylinder model (OCM) is introduced in this Letter which considers three components: the longitudinal flow, transverse flow and the temperature. A comparison of our model calculations in terms of pseudorapidity distributions with the most recent experiments is presented. To describe the experimental data at Relativistic Heavy Ion Collider (RHIC) energies ( s NN =130 and 200 GeV), a relative strong longitudinal flow and two partly overlapping cylinders are needed in the model. The difference between the different centrality events is described by the contribution of leading protons. The other parameter values do not depend on the centrality. The calculated results of the overlapping cylinder model are in agreement with the experimental data at the RHIC energies.
115903813
Angular Distributions of Target Fragments in Magnesium-Emulsion Collisions at High Energy
120712528
Alpha emission in krypton–emulsion collisions at 1.7A GeV
Abstract The multiplicity and transverse momentum distributions of alpha projectile fragments emitted in nucleus–nucleus collisions at high energies are investigated. The results calculated by the two-source model are in agreement with the experimental data of krypton–emulsion collisions at 1.7 A  GeV.
56154903
Transverse Momentum Distributions of Final-State Particles Produced in Soft Excitation Process in High Energy Collisions
Transverse momentum distributions of final-state particles produced in soft process in proton-proton (pp) and nucleus-nucleus (AA) collisions at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies are studied by using a multisource thermal model. Each source in the model is treated as a relativistic and quantum ideal gas. Because the quantum effect can be neglected in investigation on the transverse momentum distribution in high energy collisions, we consider only the relativistic effect. The concerned distribution is finally described by the Boltzmann or two-component Boltzmann distribution. Our modeling results are in agreement with available experimental data.
118977552
Preliminary design of the Wide-Field Infrared Survey Explorer (WISE)
The Wide-field Infrared Survey Explorer (WISE), a NASA MIDEX mission, will survey the entire sky in four bands from 3.3 to 23 microns with a sensitivity 1000 times greater than the IRAS survey. The WISE survey will extend the Two Micron All Sky Survey into the thermal infrared and will provide an important catalog for the James Webb Space Telescope. Using 10242 HgCdTe and Si:As arrays at 3.3, 4.7, 12 and 23 microns, WISE will find the most luminous galaxies in the universe, the closest stars to the Sun, and it will detect most of the main belt asteroids larger than 3 km. The single WISE instrument consists of a 40 cm diamond-turned aluminum afocal telescope, a two-stage solid hydrogen cryostat, a scan mirror mechanism, and reimaging optics giving 5" resolution (full-width-half-maximum). The use of dichroics and beamsplitters allows four color images of a 47'x47' field of view to be taken every 8.8 seconds, synchronized with the orbital motion to provide total sky coverage with overlap between revolutions. WISE will be placed into a Sun-synchronous polar orbit on a Delta 7320-10 launch vehicle. The WISE survey approach is simple and efficient. The three-axis-stabilized spacecraft rotates at a constant rate while the scan mirror freezes the telescope line of sight during each exposure. WISE is currently in its Preliminary Design Phase, with the mission Preliminary Design Review scheduled for July, 2005. WISE is scheduled to launch in mid 2009; the project web site can be found at www.wise.ssl.berkeley.edu.
119211238
Directed flow of transported and non-transported protons in Au+Au collisions from UrQMD model
The directed flow of inclusive, transported and non-transported (including produced) protons, as well as antiprotons, has been studied in the framework of Ultra-Relativistic Quantum Molecular Dynamics approach (UrQMD model) for Au+Au collisions at √ sNN =7.7, 11.5, 19.6, 27, 39, 62.4 and 200 GeV. The rapidity, centrality and energy dependence of directed flow for various proton groups are presented. It is found that the integrated directed flow decreases monotonically as a function of collision energy for √ sNN =11.5 GeV and beyond. However, the sign-change of directed flow of inclusive protons, seen in experimental data as a function of centrality and collision energy, can be explained by the competing effect of directed flow between transported and non-transported protons. Similarly the difference in directed flow between protons and antiprotons can be explained. Our study offers a conventional explanation on the cause of the v1 sign-change other than the antiflow component of protons alone which is argued to be linked to a phase transition.
121546377
Dependences of charged particle pseudorapidity distributions on impact parameter and center-of-mass energy in nucleus–nucleus collisions at relativistic energies
The centrality and rapidity dependence of charged particles over a wide range of center-of-mass energy are analyzed. In this framework of participant-spectator model, the interacting system of nucleus–nucleus collisions at relativistic energies is divided into four parts (sources): target spectator, target participant, projectile participant and projectile spectator. Each source is treated by using a revised Landau model. The pseudorapidity distributions calculated by four-component Landau model are found to be in agreement with experimental data of the PHOBOS and ALICE collaborations. The distribution height is mainly determined by effective nucleon number and center-of-mass energy; and the distribution width being measured by the revised width in the Landau model and the sources rapidity shifts. Furthermore, we have found two empirical relations for projectile-participant and projectile-spectator (pseudo)rapidity as functions of the center-of-mass energy.
115397124
omega phi STATES IN CHIRAL QUARK MODEL
The omega phi states with spin S = 0, 1 and 2 are dynamically studied in a chiral SU(3) quark model by solving the resonating group method (RCM) equation. It is found that the interactions of omega phi systems are attractive, while no omega phi bound state or resonance state is obtained due to the insufficiency of the strength of omega phi attractions.