Density correlators in a self-similar cascade

Multivariate density moments (correlators) of arbitrary order are obtained for the multiplicative self-similar cascade. This result is based on the calculation by Greiner, Eggers and Lipa (reference [1]) where the correlators of the logarithms of the particle densities have been obtained. The density correlators, more suitable for comparison with multiparticle data, appear to have even simpler form than those obtained in [1].Comment: 9 pages, 3 figures, uses epsfig.st

Correlation of transverse momentum and multiplicity in a superposition model of nucleus-nucleus collisions

In p-p collisions the average transverse momentum is known to be correlated with the multiplicity of produced particles. The correlation is shown to survive in a superposition model of nucleus-nucleus collisions. When properly parameterized, the correlation strength appears to be independent of the collision centrality - it is the same in p-p and central A-A collisions. However, the correlation is strongly suppressed by the centrality fluctuations.Comment: 7 pages, 2 figures, minor corrections, to appear in Phys. Rev.

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 $q$ of the moments provide single-parameter characterizations of erraticity.Comment: 10 pages LaTeX + 5 figures p

Diffractive dissociation as shadow scattering

It is pointed out that if the mechanism of diffractive production of particles is the same as that of elastic scattering, the diffractive dissociation can be calculated as shadow of non-diffractive processes. A general method of calculation is proposed. It uses the technique of the overlap matrix. A specific calculation in Uncorrelated Jet Model is performed. In this calculation the diffractive processes arise as a direct consequence of correlations induced in non-diffractive interactions by energy and momentum conservation. The most important prediction of the model is that the inclusive mass distribution of diffractive dissociation splits into non-scaling part describing the low-mass excitations and the approximately scaling part describing the high-mass excitations. The non-scaling part of the mass spectrum is dominated by single particle production and at large masses behaves as $d\sigma /dM^{2}\sim M^{-6}$. The shape of the scaling part of the spectrum in the triple-Regge region is $d\sigma /d\zeta = (\zeta log\zeta)^{-1}$ where $\zeta = M^{2}/s$. The properties of exclusive diffractive channels are also discussed

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

Intermittency in Branching Processes

We study the intermittency properties of two branching processes, one with a uniform and another with a singular splitting kernel. The asymptotic intermittency indices, as well as the leading corrections to the asymptotic linear regime are explicitly computed in an analytic framework. Both models are found to possess a monofractal spectrum with $\varphi_{q}=q-1$. Relations with previous results are discussed.Comment: 20 pages, UCLA93/TEP/2

Rising plateu from longitudinal phase-space

Longitudinal phase-space is used to study the energy dependence of the plateau in the rapidity distribution of particles produced in p–p collisions at laboratory momenta above 100 GeV. The density of particles emitted at 90$^{\circ}$ in cms shows a fast rise until 10 000 GeV and then approaches the asymptotic limit very slowly. This rise accounts for a large fraction of the experimentally observed increase

Quark-gluon structure of diffractive bumps

The diffractive dissociation of hadrons is interpreted as production of the gluonic excitations of incident particles. Regge trajectories of such gluonic excitations are calculated in the bag models and in the dual model. Good agreement is round with the observed spectra of diffractive bumps

On the possible space-time fractality of the emitting source

Using simple space-time implementation of the random cascade model we investigate numerically a conjecture made some time ago which was joining the intermittent behaviour of spectra of emitted particles with the possible fractal structure of the emitting source. We demonstrate that such details are seen, as expected, in the Bose-Einstein correlations between identical particles. \\Comment: Thoroughly rewritten and modify version, to be published in Phys. Rev.

π+−π−\pi^+ - \pi^- Asymmetry and the Neutron Skin in Heavy Nuclei

In heavy nuclei the spatial distribution of protons and neutrons is different. At CERN SPS energies production of $\pi^+$ and $\pi^-$ differs for $pp$, $pn$, $np$ and $nn$ scattering. These two facts lead to an impact parameter dependence of the $\pi^+$ to $\pi^-$ ratio in $^{208}Pb + ^{208}Pb$ collisions. A recent experiment at CERN seems to confirm qualitatively these predictions. It may open a possibility for determination of neutron density distribution in nuclei.Comment: 6 pages and 2 figures, a talk by A.Szczurek at the international conference MESON2004, June 4-8, Cracow, Polan