122800820
Universal proton rapidity distributions in high energy nucleus-nucleus collisions
Abstract Inclusive spectra of protons emitted in the interaction of 3 He ions with an energy of 4.9 GeV/nucleon with nuclei of C, Cu and Pb were measured. The analysis of these data as well as of those available on nucleus-nucleus interactions at other energies (0.8, 2.1 and 3.6 GeV/nucleon) and for other combinations of colliding nuclei (from 3 He + C to Ar + Pb) has shown that in the target nucleus fragmentation domain the invariant cross section is described by a certain universal function if we go over into the appropriate moving frame. It is natural to interpret the latter as a real physical object, i.e. a moving source. This source turns out to be highly heated (the average energy being ⪆ 90 MeV/nucleon), at the same time its inner properties (the excitation energy and distribution form) do not depend either on the collision energy or on the projectile-target combination. On the other hand, the source velocity and the number of nucleons involved in it are systematically dependent on the collision conditions.
125898346
Photons and neutral mesons from hot hadronic matter
Results from the experimental program with light ion beams and heavy target nuclei at the CERN SPS could demonstrate the occurrence of an unprecedented state of high density in hadronic matter. The thermal nature of the hadronic system has been investigated by analyzing spectra and production ratios of hadrons which reveal a large degree of rescattering of primary and secondary hadrons.Thermal photons from elementary quark-gluon interactions are considered a promising signal for the occurrence of a phase transition to the quark-gluon plasma. The predictions for thermal photons from elementary parton interactions are discussed and compared to the thermal emission rate of photons from a hot hadronic gas. Recent results from the photon spectrometers in heavy ion experiments are presented. Production cross sections of pi0 and eta mesons are determined and the projectile and target mass dependence is discussed. An upper limit for the single photon yield was determined for central O+Au reactions. Recent S+Au reactions exhibit an excess of photons over the yield expected from hadronic decays. The spectral shape of the expected single photon signal is discussed which might reveal the temperature of hot matter and indicate a phase transition.
118798878
Two particle correlations for light nuclear fragments in nucleus-nucleus collisions at 3.6-GeV/nucleon
104363365
MEASUREMENT OF THE SPECTRA OF DOUBLY CHARGED PARTICLES EMITTED BY LEAD NUCLEI BOMBARDED BY 3.6-GEV/NUCLEON PARTICLES. (IN RUSSIAN)
126031532
EMISSION OF COMPOUND LIGHT FRAGMENTS IN COLLISIONS BETWEEN RELATIVISTIC NUCLEI. (IN RUSSIAN)
109550892
A new VME-based high voltage power supply for large photomultiplier systems
Abstract We describe a new high voltage power supply, developed for the leadglass calorimeter of the WA98 experiment at CERN. The high voltage is produced for each of the 10 080 photomultiplier tubes of the detector individually, by the same number of active bases with on-board Greinacher voltage multipliers. The full VME-based HV controller system, which addresses each base via bus cables once per second, is miniaturized and fits into a single VME crate. The main advantages of this approach are the low heat dissipation, the considerably reduced amount of cabling and cost, as well as the high stability and low noise of the system.
7992539
Vacuum Einstein metrics with bidimensional Killing leaves ∗ I-Local aspects.
Abstract The solutions of vacuum Einstein's field equations, for the class of Riemannian metrics admitting a non-Abelian bidimensional Lie algebra of Killing fields, are explicitly described. They are parametrized either by solutions of a transcendental equation (the tortoise equation ), or by solutions of a linear second order differential equation in two independent variables. Metrics, corresponding to solutions of the tortoise equation, are characterized as those that admit a 3-dimensional Lie algebra of Killing fields with bidimensional leaves.
116200939
Self-Stimulated Undulator Radiation and its Possible Applications
We investigated the phenomena of self-stimulation of incoherent emission from an undulator installed in the linear accelerator or quasi-isochronous storage ring. We discuss possible applications of these phenomena for the beam physics also.