499 research outputs found

    Mini-clusters

    Get PDF
    Experimental results of mini-clusters observed in Chacaltaya emulsion chamber no.19 are summarized. The study was made on 54 single core shower upper and 91 shower clusters of E(gamma) 10 TeV from 30 families which are visible energy greater than 80 TeV and penetrate through both upper and lower detectors of the two-story chamber. The association of hadrons in mini-cluster is made clear from their penetrative nature and microscopic observation of shower continuation in lower chamber. Small P sub t (gamma) of hadrons in mini-clusters remained in puzzle

    Dissipation, noise and DCC domain formation

    Full text link
    We investigate the effect of friction on domain formation in disoriented chiral condensate. We solve the equation of motion of the linear sigma model, in the Hartree approximation, including a friction and a white noise term. For quenched initial condition, we find that even in presence of noise and dissipation domain like structure emerges after a few fermi of evolution. Domain size as large as 5 fm can be formed.Comment: 7 pages, 3 figure

    A comparison of different methods in the study of dynamical fluctuations in high energy e+e- collisions

    Get PDF
    Different methods in the study of anomalous scaling of factorial moments in high energy e+e- collisions are examined in some detail. It is shown that the horizontal and vertical factorial moments are equivalent only when they are used in combination with the cummulant variables. The influence of different reference frames and that of phase space restrictions is also discussed.Comment: 5 pages, 6 figure

    Event-by-Event Search for Charged Neutral Fluctuations in Pb - Pb Collisions at 158-A-GeV

    Full text link
    Results from the analysis of data obtained from the WA98 experiment at the CERN SPS have been presented. Some events have been filtered which show photon excess in limited ηϕ\eta-\phi zones within the overlap region of the charged particle and photon multiplicity detectors.Comment: 6 pages, 4 figure

    Thermoacoustic tomography with an arbitrary elliptic operator

    Full text link
    Thermoacoustic tomography is a term for the inverse problem of determining of one of initial conditions of a hyperbolic equation from boundary measurements. In the past publications both stability estimates and convergent numerical methods for this problem were obtained only under some restrictive conditions imposed on the principal part of the elliptic operator. In this paper logarithmic stability estimates are obatined for an arbitrary variable principal part of that operator. Convergence of the Quasi-Reversibility Method to the exact solution is also established for this case. Both complete and incomplete data collection cases are considered.Comment: 16 page

    Model of Centauro and strangelet production in heavy ion collisions

    Get PDF
    We discuss the phenomenological model of Centauro event production in relativistic nucleus-nucleus collisions. This model makes quantitative predictions for kinematic observables, baryon number and mass of the Centauro fireball and its decay products. Centauros decay mainly to nucleons, strange hyperons and possibly strangelets. Simulations of Centauro events for the CASTOR detector in Pb-Pb collisions at LHC energies are performed. The signatures of these events are discussed in detail.Comment: 19 pages, LaTeX+revtex4, 14 eps-figures and 3 table

    Effect of friction on disoriented chiral condensate formation

    Full text link
    We have investigated the effect of friction on the DCC domain formation. We solve the Newton equation of motion for the O(4) fields, with quenched initial condition. The initial fields are randomly distributed in a Gaussian form. In one dimensional expansion, on the average, large DCC domains can not be formed. However, in some particular orbits, large instabilities may occur. This possibility also greatly diminishes with the introduction of friction. But, if the friction is large, the system may be overdamped and then, there is a possibility of large DCC domain formation in some events.Comment: 9 pages, including figure

    Pseudovector vs. pseudoscalar coupling in one-boson exchange NN potentials

    Get PDF
    We examine the effects of pseudoscalar and pseudovector coupling of the pi and eta mesons in one-boson exchange models of the NN interaction using two approaches: time-ordered perturbation theory unitarized with the relativistic Lippmann-Schwinger equation, and a reduced Bethe-Salpeter equation approach using the Thompson equation. Contact terms in the one-boson exchange amplitudes in time-ordered perturbation theory lead naturally to the introduction of s-channel nucleonic cutoffs for the interaction, which strongly suppresses the far off-shell behavior of the amplitudes in both approaches. Differences between the resulting NN predictions of the various models are found to be small, and particularly so when coupling constants of the other mesons are readjusted within reasonable limits.Comment: 24 pages, 4 figure

    Threshold meson production and cosmic ray transport

    Get PDF
    An interesting accident of nature is that the peak of the cosmic ray spectrum, for both protons and heavier nuclei, occurs near the pion production threshold. The Boltzmann transport equation contains a term which is the cosmic ray flux multiplied by the cross section. Therefore when considering pion and kaon production from proton-proton reactions, small cross sections at low energy can be as important as larger cross sections at higher energy. This is also true for subthreshold kaon production in nuclear collisions, but not for subthreshold pion production.Comment: 9 pages, 1 figur
    corecore