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.)
122557716
Measurement of the polarization parameter in K+p elastic scattering at 1.60, 1.80, 2.11 and 2.31 GeV/c
Abstract The polarization parameter for K+p elastic scattering has been measured at 1.60, 1.80, 2.11 and 3.31 GeV/c incident momenta over the entire angular range with an emphasis on the backward region. The results in the extreme backward region appear to be small and consistent with zero.
119906527
MEASUREMENT OF THE POLARIZATION PARAMETER IN BACKWARD $pi$$sup +$p ELASTIC SCATTERING AT 1.60, 1.80, 2.11, AND 2.31 GeV/c.
122598679
Measurement of the polarization parameter in K$sup +$p elastic scattering
Full angular distributions of the polarization parameter in elastic ${K}^{+}p$ scattering at 1.37, 1.45, 1.60, 1.71, 1.80, 1.89, 2.11, and 2.31 GeV/c are presented. These data were obtained in an experiment at the Zero Gradient Synchrotron using a polarized proton target with arrays of scintillation and \ifmmode \check{C}\else \v{C}\fi{}erenkov counters to detect the scattered particles.
118405036
Quantitative and Conceptual Considerations for Extracting the Knudsen Number in Heavy Ion Collisions
In this article, we examine the methodology for extracting the Knudsen number (K) and the ratio of shear viscosity to entropy density ({eta}/s) developed by Drescher et al. [1]. The final result for {eta}/s turns out to be quite sensitive to Glauber parameters, particularly the parameter x, which controls the balance between N{sub part} and N{sub coll}. We also explore how alternative formulations of the functional relation between the elliptic flow and Knudsen number (K={lambda}/R{sup -}) impacts the physics conclusions, based on Pade approximants. Finally, we extend the calculation to include a limiting minimum value on the mean free path proportional to the DeBroglie wavelength. These results emphasize the importance of clarifying the initial state used in different calculations as well as the ambiguities inherent in using a transport approach in a strongly coupled regime.
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.
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.
118873547
Universal behavior of charged particle production in heavy Ion collisions
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 sqrt(s_NN) = 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/pbar-p and e+e- data. N_tot/(N_part/2) in nuclear collisions at high energy scales with sqrt(s) in a similar way as N_tot 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.
17733368
Global observables at RHIC
The first three measurements from the RHIC program were results on global observables: charged particle multiplicity (N_ch), transverse energy (E_T) and elliptic flow (v_2). They offer a look at the large-scale features of particle production in high-energy nuclear collisions, with particular insight into entropy production and collective behavior. Results from all of the RHIC experiments are discussed in light of data from lower energy nuclear collisions as well as from high-energy hadronic collisions to test our current understanding of the collision dynamics.