728 research outputs found
Soft Particle Production in Cosmic Ray Showers
Indications of a discrepancy between simulations and data on the number of
muons in cosmic ray showers exist over a large span of energies. We focus on
the excess of multi-muon bundles observed by the DELPHI detector at LEP and on
the excess in the muon number in general reported by the Pierre Auger
Observatory. Even though the primary CR energies relevant for these experiments
differ by orders of magnitude, we can find a single mechanism which can
simultaneously increase predicted muon counts for both, while not violating
constraints from accelerators or from the longitudinal shower development as
observed by the Pierre Auger Observatory. We present a brief motivation and
describe a practical implementation of such a model, based on the addition of
soft particles to interactions above a chosen energy threshold. Results of an
extensive set of simulations show the behavior of this model in various parts
of a simplified parameter space.Comment: Presented at EDS17 Bloi
Effects of massive photons from the dark sector on the muon content in extensive air showers
Inspired by recent astrophysical observations of leptonic excesses measured
by satellite experiments, we consider the impact of some general models of the
dark sector on the muon production in extensive air showers. We present a
compact approximative expression for the bremsstrahlung of a massive photon
from an electron and use it within Monte Carlo simulations to estimate the
amount of weakly interacting photon-like massive particles that could be
produced in an extensive air shower. We find that the resulting muon production
is by many orders of magnitude below the average muon count in a shower and
thus unobservable.Comment: Accepted for publication in Physics Letters B on 9 July 201
A branching model for hadronic air showers
We introduce a simple branching model for the development of hadronic showers
in the Earth's atmosphere. Based on this model, we show how the size of the
pionic component followed by muons can be estimated. Several aspects of the
subsequent muonic component are also discussed. We focus on the energy
evolution of the muon production depth. We also estimate the impact of the
primary particle mass on the size of the hadronic component. Even though a
precise calculation of the development of air showers must be left to complex
Monte Carlo simulations, the proposed model can reveal qualitative insight into
the air shower physics.Comment: In Proceedings of the 34th International Cosmic Ray Conference
(ICRC2015), The Hague, The Netherland
Mass Composition of Cosmic Rays with Combined Surface Detector Arrays
Our study exploits the Constant Intensity Cut principles applied
simultaneously to muonic and electromagnetic detectors of cosmic rays. We use
the fact that the ordering of events according to their signal sizes induced in
different types of surface detectors provides information about the mass
composition of primary cosmic-ray beam, with low sensitivity to details of
hadronic interactions. Composition analysis at knee energies is performed using
Monte Carlo simulations for extensive air showers having maxima located far
away from a hypothetical observatory. Another type of a hypothetical
observatory is adopted to examine composition of ultra-high energy primaries
which initiate vertical air showers with maxima observed near surface
detectors.Comment: Accepted for publication on PoS, PoS(ICRC2017)482, Proceedings of the
35th ICRC 2017, Busan, Kore
Study of Dispersion of Mass Distribution of Ultra-High Energy Cosmic Rays using a Surface Array of Muon and Electromagnetic Detectors
We consider a hypothetical observatory of ultra-high energy cosmic rays
consisting of two surface detector arrays that measure independently
electromagnetic and muon signals induced by air showers. Using the constant
intensity cut method, sets of events ordered according to each of both signal
sizes are compared giving the number of matched events. Based on its dependence
on the zenith angle, a parameter sensitive to the dispersion of the
distribution of the logarithmic mass of cosmic rays is introduced. The results
obtained using two post-LHC models of hadronic interactions are very similar
and indicate a weak dependence on details of these interactions.Comment: 16 pages, 5 figures, manuscript accepted to Astroparticle Physic
Testing chemical composition of highest energy comic rays
We study basic characteristics of distributions of the depths of shower
maximum in air showers caused by cosmic rays with the highest energies. The
consistency between their average values and widths, and their energy
dependences are discussed within a simple phenomenological model of shower
development independently of assumptions about detailed features of
high--energy interactions. It is shown that reliable information on primary
species can be derived within a partition method. We present examples
demonstrating implications for the changes in mass composition of primary
cosmic rays.Comment: Contribution to the 33rd International Cosmic Ray Conference, Rio de
Janeiro, Brazil, 2-9 July 201
Signal Attenuation Curve for Different Surface Detector Arrays
Modern cosmic ray experiments consisting of large array of particle detectors
measure the signals of electromagnetic or muon components or their combination.
The correction for an amount of atmosphere passed is applied to the surface
detector signal before its conversion to the shower energy. Either Monte Carlo
based approach assuming certain composition of primaries or indirect estimation
using real data and assuming isotropy of arrival directions can be used. Toy
surface arrays of different sensitivities to electromagnetic and muon
components are assumed in MC simulations to study effects imposed on
attenuation curves for varying composition or possible high energy anisotropy.
The possible sensitivity of the attenuation curve to the mass composition is
also tested for different array types focusing on a future apparatus that can
separate muon and electromagnetic component signals.Comment: Proceedings of the 14th ICATPP Conferenc
On the methods to determine signal attenuation curve for different surface arrays
Large surface arrays of current cosmic ray experiments measure the signals of
electromagnetic or muonic components or their combination. The correction to
the zenith angle (the attenuation curve) has to be taken into account before
the signal is converted to the shower energy. Either Monte Carlo simulations or
indirect estimation using collected data (Constant Intensity Cut method) can be
used. However, the assumptions of composition or isotropy used for the
determination of the attenuation curve can still influence the final physics
results such as the energy spectrum, or modify anisotropy searches and
composition analysis. Using simplified Toy Monte Carlo with an output from
CORSIKA simulations we try to find several examples of what kind of effects can
be caused by the methods of inferring the attenuation curve. Surface arrays of
different sensitivities to electromagnetic and muonic components were
considered.Comment: Contribution to the 33rd International Cosmic Ray Conference, Rio de
Janeiro, Brazil, July 201
Real-time atmospheric monitoring for the Cherenkov Telescope Array using a wide-field optical telescope
The Cherenkov Telescope Array (CTA) is the next generation of ground-based
very high energy gamma-ray instruments and is planned to be built on two sites
(one in each hemisphere) in the coming years, with full array operation
foreseen to begin 2020. The goal of performing high precision gamma-ray energy
measurements while maximizing the use of observation time demands detailed and
fast information about atmospheric conditions. Besides LIDARs designed to
monitor clouds and aerosol content of the atmosphere in the pointing direction
of the CTA telescopes, we propose to use the "FRAM" (F(/Ph)otometric Robotic
Atmospheric Monitor) device, which is a small robotic astronomical telescope
with a large field of view and a sensitive CCD camera that together ensure
precise atmospheric characterization over the complete field-of-view of the
CTA. FRAM will use stellar photometry to measure atmospheric extinction across
the field of view of the CTA without interfering with the observation (unlike
laser-based methods). This allows FRAM to operate with high temporal resolution
and provide both real-time data for on-the-fly scheduling decisions and an
offline database for calibration and selection of scientific data. The fast
robotic mount of the telescope supports quick observation of multiple fields
when the array is split and even a check of the conditions in the directions of
the upcoming observations is possible. The FRAM concept is built upon
experience gained with a similar device operated at the Pierre Auger
Observatory. A working prototype of FRAM proposed for CTA is being built in
Prague for extensive testing before deployment on site; first results and
experiences with this prototype are presented.Comment: In Proceedings of the 34th International Cosmic Ray Conference
(ICRC2015), The Hague, The Netherlands. All CTA contributions at
arXiv:1508.0589
Maximum entropy analysis of cosmic ray composition
We focus on the primary composition of cosmic rays with the highest energies
that cause extensive air showers in the Earth's atmosphere. A way of examining
the two lowest order moments of the sample distribution of the depth of shower
maximum is presented. The aim is to show that useful information about the
composition of the primary beam can be inferred with limited knowledge we have
about processes underlying these observations. In order to describe how the
moments of the depth of shower maximum depend on the type of primary particles
and their energies, we utilize a superposition model. Using the principle of
maximum entropy, we are able to determine what trends in the primary
composition are consistent with the input data, while relying on a limited
amount of information from shower physics. Some capabilities and limitations of
the proposed method are discussed. In order to achieve a realistic description
of the primary mass composition, we pay special attention to the choice of the
parameters of the superposition model. We present two examples that demonstrate
what consequences can be drawn for energy dependent changes in the primary
composition.Comment: Accepted for publication in Astroparticle Physic
- …