325 research outputs found
Multimuons events and primary composition
Nucleon decay detectors at large depths offers now a total area larger than 1000 sq m to registrate muons of energy exceeding 1 TeV. Near complete high energy muon families are detected in those arrays. An extensive 3D Monte-Carlo simulation was conducted in view to understand the spatial distribution of those events and the possible link with elementary act or primary composition. As pion or kaon parents have a very small decay probability at so high energy, multimuon phenomena occurs at high altitude where the atmospheric density is small after the most energetic collisions
The primary energy estimation of inclined giant EAS
Determination of the primary energy by surface arrays (like AGASA) through estimators (instead of total size), taken as densities at 600 m from the shower axis, needs a special procedure for inclined cascades when the maximum is close to the array (less than 2-3 radiation lengths above). According to the cascade theory and the simulations with the CORSIKA code above 10 EeV the exponential function used for conversion from inclined to vertical showers is no longer valid. As follows from simulations at energies near to 100 EeV, the density at 600 m for zenith angles 25-35 exceeds by 10% the vertical density, whereas it was assumed to be 30% lower in the previous treatments. Such treatments generate an artificial increase in the estimation of the primary cosmic ray energy. The primary spectrum reconstructed by an appropriate procedure for inclined showers confirms GZK prediction and eliminates the divergence between measurements at ultra-high energies
EAS experiment on board of the Airbus A380
We consider taking the opportunity of about 10.000 hours of test of the Airbus A380, and to install at passenger space detectors for high energy cosmic ray events. The altitude of 10 km (250 g/cm 2 ) would give opportunity to measure EAS originating from heavy primaries to energies exceeding 10 7 GeV, and also coming without interaction proton component beyond the energy of the knee. At the altitude the iron originated EAS are well developed and registering their lateral distribution in 70 meters long cabin it is possible to distinguish them from proton originated EAS. Hadron component of EAS (registered as number of secondary hadrons produced in the detector) would help in discrimination and energy estimation. On another hand, registrations of high energy protons (without EAS) would enable to measure high energy proton spectrum. The energy of the proton would be estimated via hadron multiplicity in single interaction inside the detector. We propose to use about 60 modules of 0.5 m 2 of active detectors with scintillators to detect E-M component and carbon target with lead layer to detect the hadronic component via neutron registrations
High energy cosmic rays in the low stratosphere and extrapolation above LHC energies
We review the data obtained with the emulsion chambers boarded on Concorde for the events collected above 106 GeV and their specific properties (large multiplicities, multiclusters, coplanar emission): the main features are compared to the expectation of our HDPM2 Monte Carlo collision generator. This multiproduction event generator has been adjusted and tuned, according to the
pseudo-rapidity distributions recently observed at âs = 630 GeV, as well as to previous Fermi-lab results at âs = 1800 GeV: an increase of the total inelasticity (0.72 for NSD component) near the knee region and a more important violation than usually expected for Feynmanâs scaling in forward region are observed. In such cirumstance, we have
simulated large and giant air showers taking into account, in addition, new processes, such as diquark breaking, up to energies exceeding 1020 eV for P.AUGER and EUSO experiments
Lateral distribution functions for giant air showers
We have compared the lateral analytical structure functions coming from cascade theory to the numerical distributions generated by EAS Monte Carlo simulations and to the empirical functions used in giant air showers experiments.
Introducing the Gaussian hypergeometric formalism, we have improved the analytical description in the most common topological situations and we propose a new function characterized by both terms fitted separately to the electron-positron and the muon components. Important effects in the accuracy of the core position determination
are underlined and consequences for the primary energy estimation are discussed. The consecutive treatment and interpretation of the data contained in the catalogues of Volcano Ranch and Yakutsk, completed by the most energetic event of AGASA, are presented. Results might have important implications for detector configuration of the future giant air shower arrays
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
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
Large Transverse Momenta in Statistical Models of High Energy Interactions
The creation of particles with large transverse momenta in high energy
hadronic collisions is a long standing problem. The transition from small-
(soft) to hard- parton scattering `high-pt' events is rather smooth. In this
paper we apply the non-extensive statistical framework to calculate transverse
momentum distributions of long lived hadrons created at energies from low
(sqrt(s)~10 GeV) to the highest energies available in collider experiments
(sqrt(s)~2000 GeV). Satisfactory agreement with the experimental data is
achieved. The systematic increase of the non-extensivity parameter with energy
found can be understood as phenomenological evidence for the increased role of
long range correlations in the hadronization process.
Predictions concerning the rise of average transverse momenta up to the
highest cosmic ray energies are also given and discussed.Comment: 20 pages, 10 figure
Hypermatrix factors for string and membrane junctions
The adjoint representations of the Lie algebras of the classical groups
SU(n), SO(n), and Sp(n) are, respectively, tensor, antisymmetric, and symmetric
products of two vector spaces, and hence are matrix representations. We
consider the analogous products of three vector spaces and study when they
appear as summands in Lie algebra decompositions. The Z3-grading of the
exceptional Lie algebras provide such summands and provides representations of
classical groups on hypermatrices. The main natural application is a formal
study of three-junctions of strings and membranes. Generalizations are also
considered.Comment: 25 pages, 4 figures, presentation improved, minor correction
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
- âŠ