Mini-clusters

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

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

Model of Centauro and strangelet production in heavy ion collisions

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

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

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

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

Threshold meson production and cosmic ray transport

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

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

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 $\eta-\phi$ 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

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

Multiplicity Distributions of Squeezed Isospin States

Multiplicity distributions of neutral and charged particles arising from squeezed coherent states are investigated. Projections onto global isospin states are considered. We show how a small amount of squeezing can significantly change the multiplicity distributions. The formalism is proposed to describe the phenomenological properties of neutral and charged particles anomalously produced in hadronic and nuclear collisions at very high energies.Comment: 17 pages, 6 figures sent upon request ([email protected]

Can Disordered Chiral Condensates Form? A Dynamical Perspective

We address the issue of whether a region of disordered chiral condensate (DCC), in which the chiral condensate has components along the pion directions, can form. We consider a system going through the chiral phase transition either via a quench, or via relaxation of the high temperature phase to the low temperature one within a given time scale (of order $\sim 1 \rm{fm/c}$). We use a density matrix based formalism that takes both thermal and quantum fluctuations into account non-perturbatively to argue that if the $O(4)$ linear sigma model is the correct way to model the situation in QCD, then it is very unlikely at least in the Hartree approximation, that a large ($> 10\ \rm{fm}$) DCC region will form. Typical sizes of such regions are $\sim 1 -2 \ \rm{fm}$ and the density of pions in such regions is at most of order $\sim 0.2 / \rm{fm}^3$. We end with some speculations on how large DCC regions may be formed.Comment: 21 pages LATEX, 12 figures available upon request via regular mail, PITT-94-0