6,164 research outputs found
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
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
Strangelets at Chacaltaya
We discuss the possible imprints of strangelets (i.e., lumps of Strange Quark
Matter) in Chacaltaya experimental data using model of propagation of such
objects through the atmosphere developed by us recently.Comment: gz-compressed .tar file containing LaTeX file and 4 PS files with
figures, 5 pages altogether (Nuovo Cimento cimento.cls style file attached)
Presented at Chacaltaya Meeting On Cosmic Ray Physics, La Paz - Bolivia,
23-27 July 2000. To be published in Nuovo Cimento (Proc. Suppl.
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
Evaluating Outer Segment Length as A Surrogate Measure of Peak Foveal Cone Density
Adaptive optics (AO) imaging tools enable direct visualization of the cone photoreceptor mosaic, which facilitates quantitative measurements such as cone density. However, in many individuals, low image quality or excessive eye movements precludes making such measures. As foveal cone specialization is associated with both increased density and outer segment (OS) elongation, we sought to examine whether OS length could be used as a surrogate measure of foveal cone density. The retinas of 43 subjects (23 normal and 20 albinism; aged 6–67 years) were examined. Peak foveal cone density was measured using confocal adaptive optics scanning light ophthalmoscopy (AOSLO), and OS length was measured using optical coherence tomography (OCT) and longitudinal reflectivity profile-based approach. Peak cone density ranged from 29,200 to 214,000 cones/mm2(111,700 ± 46,300 cones/mm2); OS length ranged from 26.3 to 54.5 μm (40.5 ± 7.7 μm). Density was significantly correlated with OS length in albinism (p \u3c 0.0001), but not normals (p = 0.99). A cubic model of density as a function of OS length was created based on histology and optimized to fit the albinism data. The model includes triangular cone packing, a cylindrical OS with a fixed volume of 136.6 μm3, and a ratio of OS to inner segment width that increased linearly with increasing OS length (R2 = 0.72). Normal subjects showed no apparent relationship between cone density and OS length. In the absence of adequate AOSLO imagery, OS length may be used to estimate cone density in patients with albinism. Whether this relationship exists in other patient populations with foveal hypoplasia (e.g., premature birth, aniridia, isolated foveal hypoplasia) remains to be seen
Are there strangelets in cosmic rays?
Assuming that cosmic rays entering the Earth's atmosphere contain a small
admixture of nuggets of strange quark matter in form of strangelets one can
explain a number of apparently "strange" effects observed in different cosmic
rays experiments. We shall demonstrate here that the mass spectrum of such
strangelets filles the "nuclear desert" gap existing between the heaviest
elements observed in Universe and the next "nuclear-like objects" represented
by neutron and strange stars.Comment: Presented at 19th ECRS, Florence, 200
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