645 research outputs found
Intermittency and Exotic Channels
It is pointed out that accurate measurements of short-range two-particle
correlations in like-charge and in channels should be
very helpful in determining the origin of the \lq\lq intermittency\rq\rq\
phenomenon observed recently for the like-charge pion pairs.Comment: 5 p., plain tex, preprint T94/078(Saclay), LPTHE 94/58(Orsay
Towards an unified description of total and diffractive structure functions at HERA in the QCD dipole picture
It is argued that the QCD dipole picture allows to build an unified
theoretical description -based on BFKL dynamics- of the total and diffractive
nucleon structure functions. This description is in qualitative agreement with
the present collection of data obtained by the H1 collaboration. More precise
theoretical estimates, in particular the determination of the normalizations
and proton transverse momentum behaviour of the diffractive components, are
shown to be required in order to reach definite conclusions.Comment: latex file with 5 encapsulated figures, 19 page
Unifying approach to hard diffraction
We find a consistency between two different approaches of hard diffraction,
namely the QCD dipole model and the Soft Colour Interaction approach. A
theoretical interpretation in terms of S-Matrix and perturbative QCD properties
in the small regime is proposed.Comment: 4pages, 1 figure, letter submitted for publicatio
Criticality, Fractality and Intermittency in Strong Interactions
Assuming a second-order phase transition for the hadronization process, we
attempt to associate intermittency patterns in high-energy hadronic collisions
to fractal structures in configuration space and corresponding intermittency
indices to the isothermal critical exponent at the transition temperature. In
this approach, the most general multidimensional intermittency pattern,
associated to a second-order phase transition of the strongly interacting
system, is determined, and its relevance to present and future experiments is
discussed.Comment: 15 pages + 2 figures (available on request), CERN-TH.6990/93,
UA/NPPS-5-9
Intermittency for coherent and incoherent current ensemble model
We investigate the origin of intermittency for multiparticle distribution in
momentum space, following the idea that there is a kind of power law
distribution of the space-time region of hadron emission. Using the formalism
of current ensamble model to describe boson sources we discuss intermittency
exponents for the coherent and incoherent ( chaotic) particle production
scheme.Comment: 13 pages, latex, no figure
Unified description of Bjorken and Landau 1+1 hydrodynamics
We propose a generalization of the Bjorken in-out Ansatz for fluid
trajectories which, when applied to the (1+1) hydrodynamic equations, generates
a one-parameter family of analytic solutions interpolating between the
boost-invariant Bjorken picture and the non boost-invariant one by Landau. This
parameter characterises the proper-time scale when the fluid velocities
approach the in-out Ansatz. We discuss the resulting rapidity distribution of
entropy for various freeze-out conditions and compare it with the original
Bjorken and Landau results.Comment: 20 pages, 5 figure
Wealth Condensation in Pareto Macro-Economies
We discuss a Pareto macro-economy (a) in a closed system with fixed total
wealth and (b) in an open system with average mean wealth and compare our
results to a similar analysis in a super-open system (c) with unbounded wealth.
Wealth condensation takes place in the social phase for closed and open
economies, while it occurs in the liberal phase for super-open economies. In
the first two cases, the condensation is related to a mechanism known from the
balls-in-boxes model, while in the last case to the non-integrable tails of the
Pareto distribution. For a closed macro-economy in the social phase, we point
to the emergence of a ``corruption'' phenomenon: a sizeable fraction of the
total wealth is always amassed by a single individual.Comment: 4 pages, 1 figur
On kinematics and dynamics of independent pion emission
Multiparticle boson states, proposed recently for 'independently' emitted
pions in heavy ion collisions, are reconsidered in standard second quantized
formalism and shown to emerge from a simplistic chaotic current dynamics.
Compact equations relate the density operator, the generating functional of
multiparticle counts, and the correlator of the external current to each other.
'Bose-Einstein-condensation' is related to the external pulse. A quantum master
equation is advocated for future Monte-Carlo simulations.Comment: 10 pages LaTeX, Sec.7 adde
On multiplicity correlations in the STAR data
The STAR data on the multiplicity correlations between narrow psudorapidity
bins in the pp and AuAu collisions are discussed. The PYTHIA 8.145 generator is
used for the pp data, and a naive superposition model is presented for the AuAu
data. It is shown that the PYTHIA generator with default parameter values
describes the pp data reasonably well, whereas the superposition model fails to
reproduce the centrality dependence seen in the data. Some possible reasons for
this failure and a comparison with other models are presented.Comment: 8 pages, 3 figure
Baryon Number and Electric Charge Fluctuations in Pb+Pb Collisions at SPS energies
Event-by-event fluctuations of the net baryon number and electric charge in
nucleus-nucleus collisions are studied in Pb+Pb at SPS energies within the HSD
transport model. We reveal an important role of the fluctuations in the number
of target nucleon participants. They strongly influence all measured
fluctuations even in the samples of events with rather rigid centrality
trigger. This fact can be used to check different scenarios of nucleus-nucleus
collisions by measuring the multiplicity fluctuations as a function of
collision centrality in fixed kinematical regions of the projectile and target
hemispheres. The HSD results for the event-by-event fluctuations of electric
charge in central Pb+Pb collisions at 20, 30, 40, 80 and 158 A GeV are in a
good agreement with the NA49 experimental data and considerably larger than
expected in a quark-gluon plasma. This demonstrate that the distortions of the
initial fluctuations by the hadronization phase and, in particular, by the
final resonance decays dominate the observable fluctuations.Comment: 24 pages, 17 figures, to be published in Phys. Rev. C; new results on
electric charge fluctuations in central Pb+Pb collisions at SPS energies have
been adde
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