120606050
Monte Carlo simulation of a gas-sampled hadron calorimeter
Abstract A prototype of the OPAL barrel hadron calorimeter, which is a gas-sampled calorimeter using plastic streamer tubes, was exposed to pions at energies between 1 and 7 GeV. The response of the detector was simulated using the CERN GEANT3 Monte Carlo program. By using the observed high energy muon signals to deduce details of the streamer formation, the Monte Carlo program was able to reproduce the observed calorimeter response. The behavior of the hadron calorimeter when placed behind a lead glass electromagnetic calorimeter was also investigated.
120716454
Evidence of muonium formation using thin gold foils in vacuum
125730338
Proposal for an Extension of E151/227 to Study Neutrino Interactions in Deuterium in the 15-Foot Bubble Chamber with Plates
119364085
DOUBLE-HYPERFRAGMENT EVENT PRODUCED BY K$sup -$ INTERACTION AT 2.3 Bev/c IN NUCLEAR EMULSION
An event is shown that consists of two hyperfragments and a meson (K/sup +) coming from a single interaction star found in a nuclear emulsion stack exposed to a meson (K/sup -/) beam at 2.3 and 2.5 Bev/c. Unique identification of the hyperfragments is impossible, but the binding energy favors LAMBDA H/sup 4/ or LAMBDA He/sup 4/. The nature of the production mechanism cannot be determined on the basis of the iniormation available in this single event. (C.E.S.)
121317828
MEASUREMENT OF POLARIZATION IN K$sup +$p ELASTIC SCATTERING AT 1.37, 1.45, 1.71, AND 1.89 GeV/c AND PHASE-SHIFT ANALYSIS.
117056598
Search for Penetrating Massive Neutral Particles Produced in High Energy Proton Collisions
1646349
Heavy ion physics at the LHC with the ATLAS detector
The ATLAS detector at CERN will provide a high-resolution longitudinally segmented calorimeter and precision tracking for the upcoming study of heavy ion collisions at the LHC ( GeV). The calorimeter covers |η| < 5 with both electromagnetic and hadronic sections, while the inner detector spectrometer covers |η| < 2.5. ATLAS will study a full range of observables necessary to characterize the hot and dense matter formed at the LHC. Global measurements (particle multiplicities, collective flow) will provide access into its thermodynamic and hydrodynamic properties. Measuring complete jets out to 100's of GeV will allow detailed studies of energy loss and its effect on jets. Quarkonia will provide a handle on deconfinement mechanisms. ATLAS will also study the structure of the nucleon and nucleus using forward physics probes and ultraperipheral collisions, both enabled by segmented zero degree calorimeters.
110159434
The data collection modules and ATM-based event builder for the PHENIX experiment at RHIC
The PHENIX experiment at RHIC will study 200 AGeV Au+Au collisions as well as pp and pA collisions at higher energies. In order to study hard processes or high-mass vector mesons, which have small cross sections, PHENIX emphasizes measuring charged hadrons, leptons, and photons at a high rate in a limited aperture. At design RHIC luminosity, the minimum-bias interaction rate will be approximately 1000 Hz with an average zero-suppressed event size of 200 kB. We will discuss two major parts of the PHENIX online system: the data collection modules (DCM) and the event builder (EvB). The DCMs use a combination of FPGAs and DSPs to perform online pedestal subtraction, zero-suppression, and data formatting. They have been fully constructed and tested and are able to deliver data at a maximum rate of 160 MB/s. The event builder consists of commercially available PCs and a 10 Gb/s ATM switch. The software for it has been developed using Windows NT, Winsock-2 and Visual C++, allowing a fully object-oriented design. Currently, we are running configurations with up to 4 sources and 3 destinations that can deliver data at /spl sim/10 MB/sec/node and performance is improving steadily.
122715066
Heavy-ion physics with the ATLAS detector at the LHC
The ATLAS experiment will participate in the Heavy Ion program at the Large Hadron Collider (LHC) and will use its large acceptance, high granularity calorimeters, silicon tracking detectors, and muon spectrometers to study hard scattering processes and jet quenching, quarkonia production and suppression, and global observables in Pb+Pb collisions. The longitudinal and fine transverse segmentation of the ATLAS electromagnetic calorimeter gives ATLAS unique capabilities for measuring complete jets and photons. Brookhaven National Laboratory, Columbia University, Iowa State University, and Stony Brook University propose a focused program to take advantage of ATLAS’s strengths to study the physics of high-energy parton interactions with the quark-gluon plasma (QGP), the physics of Debye screening of Q-Q̄ states in the QGP, and the physics of initial particle production and thermalization to characterize the properties of the QGP created in heavy ion collisions at the LHC. The proposed program can be accomplished for modest cost, will provide substantial physics impact and will have a positive impact on the physics program at the Relativistic Heavy Ion Collider (RHIC) due to the strong involvement of the proposing institutions in the RHIC program. Participation of US groups will strengthen the existing (and growing) ATLAS heavy ion program by bringing physics and analysis expertise developed at RHIC and will allow the US Nuclear Physics program to participate in an experiment that will have subtantial physics impact on the heavy ion community.
14828282
Universal behavior of charged particle production in heavy ion collisions at RHIC energies
The PHOBOS experiment at RHIC has measured the multiplicity of primary charged particles as a function of centrality and pseudorapidity in Au+Au collisions at √SNN = 19.6, 130 and 200 GeV. Two kinds of universal behavior are observed in charged particle production in heavy ion collisions. The first is that forward particle production, over a range of energies, follows a universal limiting curve with a non-trivial centrality dependence. The second arises from comparisons with pp/pp and e+e− data. 〈Nch〉/〈Npart/2〉 in nuclear collisions at high energy scales with √s in a similar way as Nch in e+e− collisions and has a very weak centrality dependence. This feature may be related to a reduction in the leading particle effect due to the multiple collisions suffered per participant in heavy ion collisions.
16943370
The Origin of the Difference between Multiplicities in e+e- Annihilation and Heavy Ion Collisions
Multiplicities in e+e- annihilation and relativistic heavy ion collisions show remarkable similarities at high energies. A thermal-statistical model is proposed to explain the differences which occur mainly at low beam energies. Two different calculations are performed, one using an approximate thermodynamic relationship, the other using a full thermal model code. The results are in qualitative agreement, suggesting that the interplay of baryon density and temperature tends to systematically suppress the total multiplicity at lower beam energies.