318 research outputs found
Erraticity of Rapidity Gaps
The use of rapidity gaps is proposed as a measure of the spatial pattern of
an event. When the event multiplicity is low, the gaps between neighboring
particles carry far more information about an event than multiplicity spikes,
which may occur very rarely. Two moments of the gap distrubiton are suggested
for characterizing an event. The fluctuations of those moments from event to
event are then quantified by an entropy-like measure, which serves to describe
erraticity. We use ECOMB to simulate the exclusive rapidity distribution of
each event, from which the erraticity measures are calculated. The dependences
of those measures on the order of of the moments provide single-parameter
characterizations of erraticity.Comment: 10 pages LaTeX + 5 figures p
The model of particle production by strong external sources
Using some knowledge of multiplicity disributions for high energy reactions,
it is possible to propose a simple analytical model of particle production by
strong external sources. The model describes qualitatively most peculiar
properties of the distributions. The generating function of the distribution
varies so drastically as it can happen at phase transitions.Comment: 7 pages, no Figures, LATEX; Eq. (10) corrected, Eqs (25), (26) added,
ref [20] corrected; Pisma v Zhetf 84, n5 (2006
Universal behavior of multiplicity differences in quark-hadron phase transition
The scaling behavior of factorial moments of the differences in
multiplicities between well separated bins in heavy-ion collisions is proposed
as a probe of quark-hadron phase transition. The method takes into account some
of the physical features of nuclear collisions that cause some difficulty in
the application of the usual method. It is shown in the Ginzburg-Landau theory
that a numerical value of the scaling exponent can be determined
independent of the parameters in the problem. The universality of
characterizes quark-hadron phase transition, and can be tested directly by
appropriately analyzed data.Comment: 15 pages, including 4 figures (in epsf file), Latex, submitted to
Phys. Rev.
Critical Behavior of Hadronic Fluctuations and the Effect of Final-State Randomization
The critical behaviors of quark-hadron phase transition are explored by use
of the Ising model adapted for hadron production. Various measures involving
the fluctuations of the produced hadrons in bins of various sizes are examined
with the aim of quantifying the clustering properties that are universal
features of all critical phenomena. Some of the measures involve wavelet
analysis. Two of the measures are found to exhibit the canonical power-law
behavior near the critical temperature. The effect of final-state randomization
is studied by requiring the produced particles to take random walks in the
transverse plane. It is demonstrated that for the measures considered the
dependence on the randomization process is weak. Since temperature is not a
directly measurable variable, the average hadronic density of a portion of each
event is used as the control variable that is measurable. The event-to-event
fluctuations are taken into account in the study of the dependence of the
chosen measures on that control variable. Phenomenologically verifiable
critical behaviors are found and are proposed for use as a signature of
quark-hadron phase transition in relativistic heavy-ion collisions.Comment: 17 pages (Latex) + 24 figures (ps file), submitted to Phys. Rev.
Self-Similarity of the Negative Binomial Multiplicity Distributions
The negative binomial distribution is self similar: If the spectrum over the
whole rapidity range gives rise to a negative binomial, in absence of
correlation and if the source is unique, also a partial range in rapidity gives
rise to the same distribution. The property is not seen in experimental data,
which are rather consistent with the presence of a number of independent
sources. When multiplicities are very large self similarity might be used to
isolate individual sources is a complex production process.Comment: 10 pages, plane tex, no figure
A Color Mutation Model of Soft Interaction in High Energy Hadronic Collisions
A comprehensive model, called ECOMB, is proposed to describe multiparticle
production by soft interaction. It incorporates the eikonal formalism, parton
model, color mutation, branching and recombination. The physics is conceptually
opposite to the dynamics that underlies the fragmentation of a string. The
partons are present initially in a hadronic collision; they form a single,
large, color-neutral cluster until color mutation of the quarks leads to a
fission of the cluster into two color-neutral subclusters. The mutation and
branching processes continue until only pairs are left in each small
cluster. The model contains self-similar dynamics and exhibits scaling behavior
in the factorial moments. It can satisfactorily reproduce the intermittency
data that no other model has been able to fit.Comment: 24 pages including 11 figures in revtex epsf styl
Erraticity Analysis of Soft Production by ECOMB
Event-to-event fluctuations of the spatial patterns of the final states of
high-enery collisions, referred to as erraticity, are studied for the data
generated by a soft-interaction model called ECOMB. The moments do
not show simple power-law dependences on the bin size. New measures of
erraticity are proposed that generalizes the bin-size dependence. The method
should be applied not only to the soft production data of NA22 and NA27 to
check the dynamical content of ECOMB, but also to other collision processes,
such as annihilation and heavy-ion collisions.Comment: 8 pages (Latex) + 7 figures (ps file), submitted to Phys. Rev.
Organizational and dynamical aspects of a small network with two distinct communities : Neo creationists vs. Evolution Defenders
Social impacts and degrees of organization inherent to opinion formation for
interacting agents on networks present interesting questions of general
interest from physics to sociology. We present a quantitative analysis of a
case implying an evolving small size network, i.e. that inherent to the ongoing
debate between modern creationists (most are Intelligent Design (ID) proponents
(IDP)) and Darwin's theory of Evolution Defenders (DED)). This study is carried
out by analyzing the structural properties of the citation network unfolded in
the recent decades by publishing works belonging to members of the two
communities. With the aim of capturing the dynamical aspects of the interaction
between the IDP and DED groups, we focus on key quantities, namely, the
{\it degree of activity} of each group and the corresponding {\it degree of
impact} on the intellectual community at large. A representative measure of the
former is provided by the {\it rate of production of publications} (RPP),
whilst the latter can be assimilated to the{\it rate of increase in citations}
(RIC). These quantities are determined, respectively, by the slope of the time
series obtained for the number of publications accumulated per year and by the
slope of a similar time series obtained for the corresponding citations. The
results indicate that in this case, the dynamics can be seen as geared by
triggered or damped competition. The network is a specific example of marked
heterogeneity in exchange of information activity in and between the
communities, particularly demonstrated through the nodes having a high
connectivity degree, i.e. opinion leaders.Comment: 10 pages, 4 figures, 2 tables, 52 reference
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