Intriguing feature of multiplicity distributions

Multiplicity distributions, P(N), provide valuable information on the mechanism of the production process. We argue that the observed P(N) contain more information (located in the small N region) than expected and used so far. We demonstrate that it can be retrieved by analysing specific combinations of the experimentally measured values of P(N) which we call {it modified combinants, Cj, and which show distinct oscillatory behavior, not observed in the usual phenomenological forms of the P(N) used to fit data. We discuss the possible sources of these oscillations and their impact on our understanding of the multiparticle production mechanism.Comment: Invited talk presented at XLVIII International Symposium on Multiparticle Dynamics (ISMD2018), 3 to 7 September 2018, Singapore; 10 pages, 6 figures. To be published in EPJ Web of Conference

Transverse momentum versus multiplicity fluctuations in high-energy nuclear collisions

We discuss recently measured event-by-event fluctuations of transverse momentum and of multiplicity in relativistic heavy-ion collisions. It is shown that the non-monotonic behavior of the p_T-fluctuations as a function of collision centrality can be fully explained by the observed non-monotonic multiplicity fluctuations. A possible mechanism responsible for the multiplicity fluctuations is also considered.Comment: 5 pages, 3 figures, revised & extended, to appear in Phys. Rev.

Multiplicity fluctuations in the string clustering approach

We present our results on multiplicity fluctuations in the framework of the string clustering approach. We compare our results --with and without clustering formation-- with CERN SPS NA49 data. We find a non-monotonic behaviour of these fluctuations as a function of the collision centrality, which has the same origin as the observed fluctuations of transverse momentum: the correlations between the produced particles due to the cluster formation.Comment: 16 pages, 4 figures, revte

Self-organized criticality in atmospheric cascades

We argue that atmospheric cascades can be regarded as example of the self-organized criticality and studied by using Levy flights and nonextensive approach. It allows us to understand the scale-invariant energy fluctuations inside cascades in a natural way.Comment: gz-compressed .tar file containing LaTeX file and 5 PS files with figures, 4 pages altogether (Nucl. Phys. B style, espcrc2.sty file attached) Presented at XI International Symposium On Very High Energy Cosmic Ray Interaction, Campinas, Brazil, July 17-21, 2000. To be published in Nucl. Phys. B (Proc. Suppl.). Some typos correcte

Can Centauros or Chirons be the first observations of evaporating mini black holes?

We argue that the signals expected from the evaporation of mini black holes - predicted in TeV-scale gravity models with large extra dimensions, and possibly produced in ultra high energy collisions in the atmosphere - are quite similar to the characteristics of the Centauro events, an old mystery of cosmic-ray physics.Comment: 14 pages, LaTeX, one Table, uses rotate.sty and rotcapt.sty. References added, typos corrected, footnotes moved into the tex

A look at multiparticle production via modified combinants

As shown recently, one can obtain additional information from the measured charged particle multiplicity distributions, $P(N)$, by investigating the so-called modified combinants, $C_j$, extracted from them. This information is encoded in the observed specific oscillatory behaviour of $C_j$, which phenomenologically can be described only by some combinations of compound distributions based on the Binomial Distribution. So far this idea has been checked in $pp$ and $e^+e^-$ processes (where observed oscillations are spectacularly strong). In this paper, we continue observation of multiparticle production from the modified combinants perspective by investigating dependencies of the observed oscillatory patterns on type of colliding particles, their energies and the phase space where they are observed. We also offer some tentative explanations based on different types of compound distributions and stochastic branching processes.Comment: 11 pages, 7 figures and 1 table. This reworked version has been accepted for publication by EPJ

Locally anisotropic momentum distributions of hadrons at freeze-out in relativistic heavy-ion collisions

A spheroidal anisotropic local momentum distribution is implemented in the statistical model of hadron production. We show that this form leads to exactly the same ratios of hadronic abundances as the equilibrium distributions, if the temperature is identified with a characteristic transverse-momentum scale. Moreover, to a very good approximation the transverse-momentum spectra of hadrons are the same for isotropic and anisotropic systems, provided the size of the system at freeze-out is appropriately adjusted. We further show that this invariance may be used to improve the agreement between the model and experimental HBT results.Comment: 7 pages, 4 figure

Rapidity Spectra Analysis in Terms of Non Extensive Statistic Approach

We provide description of rapidity spectra of particles produced in p-anti-p collisions using anomalous diffusion approach to account for their non-equilibrium character. In particular, we exhibit connection between multiproduction processes and anomalous diffusion described through the nonlinear Focker-Planck equation with nonlinearity given by the nonextensivity parameter q describing the underlying Tsallis q-statistics and demonstrate how it leads to the Feynman scaling violation in these collisions. The q parameter obtained this way turns out to be closely connected to parameter 1/k converting the original poissonian multiplicity distribution to its observed Negative Binomial form. The inelasticity of reaction has been also calculated and found to slightly decrease with the increasing energy of reaction. Keywords: inelasticity, rapidity spectra, nonextensivityComment: 4 pages, 4 figures, Presented at XII International Symposium on Very High Energy Cosmic Ray Interactions, CERN, Switzerland, 15-20 July 200

Single-freeze-out model for ultra relativistic heavy-ion collisions at sNN=2.76\sqrt{s_{\rm NN}}=2.76 TeV and the LHC proton puzzle

The single-freeze-out model with parametrized hypersurface and flow geometry is employed to analyze the transverse-momentum spectra of hadrons produced in the Pb+Pb collisions at the collision energy of {$\sqrt{s_{\rm NN}}=2.76$ TeV} at the CERN Large Hadron Collider (LHC). With the notable exception for protons and antiprotons, we find a very good agreement between the model results and the data for the measured hadron species. The additional analysis of the HBT radii of pions helps us to select, from several different types of freeze-out studied in this work, the most realistic form of the freeze-out hypersurface. We find that discrepancy ratio between the model and experiment for the proton/antiproton spectra depends on $p_T$, dropping from 2 in the soft region to 1 around $p_T=1.5$ GeV.Comment: 9 pages, 10 figure