LPM effect and primary energy estimations

The distortion of the electron cascade development under LPM effects is now admitted; it consists of an increase of depth of showers origin, of shower maximum T sum max, a decrease of the number of particles at maximum N sub max and results in a flattening and a widening of the cascade transition curve. Connected with the influence of multiple Coulomb scattering on basic electromagnetic processes (bremsstrahlung, pair production), this effect appears at high energy with a threshold dependent on the density of the medium (more than 10 TeV for lead, more than 10 sup 6 TeV in air). Consequently, the electromagnetic components of hadron induced showers in lead and EAS in air calculated for the same hadronic cascades in the different alternative, including or not the LPM effect are examined here

Specialization and Technology in Mexico: A Virtual Pattern of Development and Competitiveness?

By the end of the 80s and the beginning of the 90s, Mexico has shown important transformations in its pattern of industrialization and competitiveness. It is hard to determine whether this pattern might become a successful one in the near future. However, some points about the features which are presently prevailing can be emphasized: (1) The structural change in the composition of Mexican exports and the improved performance in competitiveness when the dynamics in market shares are considered. This pattern is mainly related to again in competitiveness which is supported by what has been defined in terms of static allocative efficiency. Still, when actual competitiveness is analyzed, domestic industry appears to maintain the traditional structure which emerged during the ISI period. In a sense, sectors and firms that developed technical capabilities and economies of scale in this period possess higher opportunities to achieve actual competitiveness. (2) The specificity of this pattern seems to support the hypothesis that the new Mexican specialization has not been followed by a change in both the development of production capacity and technological capabilities. Moreover, when the analysis is extended in the most recent years, it seems to confirm how the maquila industry is one of the leading actors in industrial modernization. The diffusion of this type of industry introduces only very weak linkages with domestic productive sectors, strengthening the specificities of the competitiveness pattern in terms of production capacity and technological capabilities

Coplanar emission near the LHC energy range (observed with XREC in the stratosphere)

The alignment of very high energy secondary cosmic rays was observed at both stratospheric and mountain altitudes by several X-ray emulsion chamber experiments. Extensive simulation with CORSIKA demonstrates that such phenomena can be explained by fluctuations with standard physics. However, in the case of two events observed in the stratosphere, specific features contradicts such explanation. According to the properties of those events with a minimal cascading, we explore the hints of new physics which could explain the alignment in terms of relativistic strings and diquark breaking. One description of the consequent coplanar emission expected in colliders is proposed

Comparison of simulated longitudinal profiles of hadronic air showers with MASS2 balloon data

The KASKADE and CORSIKA air shower generators are compared to the data collected by MASS2 balloon experiment in 1991. The test of longitudinal profile for proton, helium and muon flux production provide good constraints on these air shower generators. KASKADE and CORSIKA especially with the new simulator UrQMD for low energies are found to fit these data well. This study is limited to a comparison of longitudinal profiles and therefore does not provide constraints on the overall shower development.Comment: to be published in Astroparticle Physic

Underground Muon Physics with the MACRO experiment

Underground muon events detected by the MACRO experiment at Gran Sasso have been studied for different purposes. The studies include the vertical muon intensity measurement, multiplicity distribution, lateral and angular muon distribution and searches for substructures inside muon bundles. These analyses have contributed to bring new insights in cosmic ray physics, in particular in the framework of primary cosmic ray composition studies. Moreover, this activity allows the testing and tuning of Monte Carlo simulations, in particular for aspects associated with models of hadronic interactions and muon propagation through the rock.Comment: 6 pages, 4 EPS figures included with epsfig, uses espcrc2.sty Talk given at the Sixth Topical Seminar on Neutrino and Astroparticle Physics, San Miniato, Italy, 17-21 May 199

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

High energy hadrons in EAS at mountain altitude

An extensive simulation has been carried out to estimate the physical interpretation of dynamical factors such as , in terms of high energy interaction features, concentrated in the present analysis on the average transverse momentum. It appears that the large enhancement observed for versus primary energy, suggesting in earliest analysis a significant rise of with energy, is only the result of the limited resolution of the detectors and remains in agreement with a wide range of models used in simulations.Comment: 13 pages, 6 PostScript figures, LaTeX Subm. to JPhys

Depth of maximum of extensive air showers and cosmic ray composition above 10**17 eV in the geometrical multichain model of nuclei interactions

The depth of maximum for extensive air showers measured by Fly's Eye and Yakutsk experiments is analysed. The analysis depends on the hadronic interaction model that determine cascade development. The novel feature found in the cascading process for nucleus-nucleus collisions at high energies leads to a fast increase of the inelasticity in heavy nuclei interactions without changing the hadron-hadron interaction properties. This effects the development of the extensive air showers initiated by heavy primaries. The detailed calculations were performed using the recently developed geometrical multichain model and the CORSIKA simulation code. The agreement with data on average depth of shower maxima, the falling slope of the maxima distribution, and these distribution widths are found for the very heavy cosmic ray mass spectrum (slightly heavier than expected in the diffusion model at about 3*10**17 eV and similar to the Fly's Eye composition at this energy).Comment: 11pp (9 eps figures

On the Possible Common Nature of Double Extensive Air Showers and Aligned Events

Double Extensive Air Showers and aligned events were discovered at energies E {\gtsim} 1016 eV over fourth century back. But up to now there is no sufficiently identical explanation of their nature. In this paper it is expected that both types of events are the result of breakup of the string formed in the collisions of super high energy particles

Specific Interactions at Cosmic Ray Energies for Extensive Air Showers Experiments

The HIJING and VENUS models of relativistic hadron-nucleus and nucleus-nucleus collisions are used to study interactions of hadron-hadron, hadron-nitrogen and nucleus-nitrogen collisions, specific for the extensive air shower developments initiated by cosmic rays in the atmosphere. The transverse energy, transverse momenta and spectra of secondary particles as well as their energy and mass dependence have been investigated in detail. Results are presented with particular emphasis on the contributions of minijets in HIJING model and validity of superposition models in this energy range.Comment: latex, revtex, 44 pages, 20 figures, 7 tables , submitted to Astroparticle Physic