291. Search for a correlation between the UHECRs measured by the Pierre Auger Observatory and the Telescope Array and the neutrino candidate events from IceCubeAsen Christov, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: We have conducted three searches for correlations between
ultra-high energy cosmic rays detected by the Telescope Array
and the Pierre Auger Observatory, and high-energy neutrino
candidate events from IceCube. Two cross-correlation analyses
with UHECRs are done: one with 39 cascades from the IceCube
‘high-energy starting events’ sample and the other with 16
high-energy ‘track events’. The angular separation between the
arrival directions of neutrinos and UHECRs is scanned over.
The same events are also used in a separate search using a
maximum likelihood approach, after the neutrino arrival
directions are stacked. To estimate the significance we assume
UHECR magnetic deflections to be inversely proportional to
their energy, with values 3◦, 6◦ and 9◦ at 100 EeV to allow for
the uncertainties on the magnetic field strength and UHECR
charge. A similar analysis is performed on stacked UHECR
arrival directions and the IceCube sample of through-going
muon track events which were optimized for neutrino point-
source searches.
Keywords: ultra-high energy cosmic rays, Pierre Auger Observatory, Telescope Array, high-energy neutrinos, IceCube, correlation search
Published in RUNG: 08.03.2016; Views: 4970; Downloads: 192
 Full text (1,11 MB) |
292. Education, Outreach and Public Relations of the Pierre Auger ObservatoryCharles Timmermans, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: The scale and scope of the physics studied at the Pierre Auger
Observatory continue to offer significant opportunities for
original outreach work. Education, outreach and public
relations of the Auger Collaboration are coordinated in a
dedicated task whose goals are to encourage and support
a wide range of efforts that link schools and the public with
the Auger scientists and the science of cosmic rays, particle
physics, and associated technologies. We focus on the impact of
the Collaboration in Mendoza Province, Argentina and beyond.
The Auger Visitor Center in Malargüe has hosted over 95,000
visitors since 2001, and a fifth Collaboration-sponsored
science fair was held on the Observatory campus in November
2014. The Rural Schools Program, which is run by Observatory
staff and which brings cosmic-ray science and infrastructure
improvements to remote schools, continues to broaden its
reach. Numerous online resources, video documentaries, and
animations of extensive air showers have been created for wide
public release. Increasingly, collaborators draw on these
resources to develop Auger related displays and outreach events
at their institutions and in public settings to disseminate the
science and successes of the Observatory worldwide. We also
highlight education and outreach activities associated with the
planned upgrade of the Observatory’s detector systems and
future physics goals.
Keywords: Pierre Auger Observatory, cosmic rays physics, education, outreach, public relations
Published in RUNG: 03.03.2016; Views: 4626; Downloads: 184
Full text (4,12 MB) |
293. AugerNext: R&D studies at the Pierre Auger Observatory for a next generation ground-based ultra-high energy cosmic-ray experimentAndreas Haungs, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: The findings so far of the Pierre Auger Observatory and those
of the Telescope Array define some requirements for a possible
next generation global cosmic ray observatory: it needs to be
considerably increased in size, it needs enhanced sensitivity
to composition, and it has to cover the full sky. At the Pierre
Auger Observatory, AugerNext aims to conduct some innovative
initial research studies on a design of a sophisticated hybrid
detector fulfilling these demands. Within a European supported
ASPERA/APPEC (Astroparticle Physics European Consortium)
project for the years 2011-2014, such R&D studies primarily
focused on the following areas: i) consolidation of the
detection of cosmic rays using MHz radio antennas; ii) proof-
of-principle of cosmic ray microwave detection; iii) test of
the large-scale application of new generation photo sensors;
iv) generalization of data communication techniques; and v)
development of new schemes for muon detection with surface
arrays. The AugerNext Consortium consists of 14 principal
investigators from 9 countries. This contribution summarizes
some achievements of the R&D studies within the AugerNext
project.
Keywords: ultra-high energy cosmic-ray experiments, Pierre Auger Observatory, Telescope Array, AugerNext research and development study
Published in RUNG: 03.03.2016; Views: 5027; Downloads: 198
Full text (594,23 KB) |
294. Measurement of the water-Cherenkov detector response to inclined muons using an RPC hodoscopePedro Assis, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: The Pierre Auger Observatory operates a hybrid detector
composed of a Fluorescence Detector and a Surface Detector
array. Water-Cherenkov detectors (WCD) are the building blocks
of the array and as such play a key role in the detection of
secondary particles at the ground. A good knowledge of the
detector response is of paramount importance to lower
systematic uncertainties and thus to increase the capability
of the experiment in determining the muon content of the
extensive air showers with a higher precision.
In this work we report on a detailed study of the detector
response to single muons as a function of their trajectories
in the WCD. A dedicated Resistive Plate Chambers (RPC)
hodoscope was built and installed around one of the detectors.
The hodoscope is formed by two stand-alone low gas flux
segmented RPC detectors with the test water-Cherenkov detector
placed in between. The segmentation of the RPC detectors is of
the order of 10 cm. The hodoscope is used to trigger and
select single muon events in different geometries. The signal
recorded in the water-Cherenkov detector and performance
estimators were studied as a function of the trajectories of
the muons and compared with a dedicated simulation.
An agreement at the percent level was found, showing that the
simulation correctly describes the tank response.
Keywords: Pierre Auger Observatory, Water-Cherenkov detectors, detector calibration, inclined cosmic ray muons, Resistive Plate Chambers (RPC) hodoscope
Published in RUNG: 03.03.2016; Views: 4774; Downloads: 198
Full text (1,27 MB) |
295. Upgrade of the Pierre Auger Observatory (AugerPrime)Ralph Engel, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: The data collected with the Pierre Auger Observatory have led
to a number of surprising discoveries. While a strong
suppression of the particle flux at the highest energies has
been established unambiguously, the dominant physics processes
related to this suppression could not be identified.
Within the energy range covered by fluorescence detector
observations with sufficient statistics, an unexpected change
of the depth of maximum distribution is found. Using LHC-tuned
interaction models these observations can be understood as a
correlated change of the fluxes of different mass groups.
On the other hand, they could also indicate a change of
hadronic interactions above the energy of the ankle.
Complementing the water Cherenkov detectors of the surface
array with scintillator detectors will, mainly through the
determination of the muonic shower component, extend the
composition sensitivity of the Auger Observatory into the flux
suppression region. The upgrade of the Auger Observatory will
allow us to estimate the primary mass of the highest energy
cosmic rays on a shower-by-shower basis. In addition to
measuring the mass composition the upgrade will open the
possibility to search for light primaries at the highest
energies, to perform composition-selected anisotropy studies,
and to search for new phenomena including unexpected changes
of hadronic interactions. After introducing the physics
motivation for upgrading the Auger Observatory the planned
detector upgrade is presented. In the second part
of the contribution the expected performance and improved
physics sensitivity of the upgraded Auger Observatory are
discussed.
Keywords: Pierre Auger Observatory, ultra-high energy cosmic rays, elemental composition sensitivity, Auger upgrade (AugerPrime), muonic shower component, scintillator detectors
Published in RUNG: 03.03.2016; Views: 4428; Downloads: 222
Full text (659,02 KB) |
296. Solar Cycle Modulation of Cosmic Rays Observed with the Low Energy Modes of the Pierre Auger ObservatoryJimmy Masías-Meza, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: The low energy modes of the surface detector array of the
Pierre Auger Observatory record variations in the flux of low
energy secondary particles with extreme detail. These two modes
consist of recording (1) the rate of signals for energies
between ∼15 MeV and ∼100 MeV (the Scaler mode) and (2) the
calibration charge histograms of the individual pulses detected
by each water-Cherenkov station, covering different energy
channels up to ∼1 GeV (the Histogram mode). Previous work has
studied the flux of galactic cosmic rays on short and
intermediate time scales (i.e. from minutes to weeks) using
these low energy modes. In this work, after including a long-
term correction to the response of the detectors, we present
the first long-term analysis of the flux of cosmic rays using
scalers and two energy bands of the calibration histograms.
We show its sensitivity to the solar cycle variation and its
relation to the solar modulation of cosmic rays for an 8-year
period.
Keywords: Pierre Auger Observatory, Surface Detector, secondary cosmic rays, scaler mode, charge histogram mode, solar cycle modulation
Published in RUNG: 03.03.2016; Views: 4908; Downloads: 203
Full text (533,18 KB) |
297. Combined fit of spectrum and composition data as measured by the Pierre Auger ObservatoryAndrea Di Matteo, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: We present a combined fit of both flux and composition of
ultra-high energy cosmic rays as measured by the Pierre Auger
Observatory. The fit has been performed for energies above
5 × 10[sup]18 eV, i.e. the region of the all-particle spectrum
above the so-called “ankle” feature. A simple astrophysical model consisting of identical sources has been adopted, where
nuclei are injected with a rigidity dependent mechanism and the
sources are uniformly distributed in a comoving volume.
The fit results suggest a source model characterized by
relatively low maximum injection energies and hard spectral
indices. The impact of different sources of systematic
uncertainties in the above result is discussed.
Keywords: Pierre Auger Observatory, ultra-high energy cosmic rays, energy spectrum, elemental composition, combined data fit
Published in RUNG: 03.03.2016; Views: 4612; Downloads: 231
Full text (704,98 KB) |
298. Measurement of the muon content in air showers at the Pierre Auger ObservatoryLaura Collica, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: The muon content of extensive air showers is an
observable sensitive to the primary composition and to
the hadronic interaction properties. We present here
different methods which allow us to estimate the muon number
at the ground level and the muon production depth by
exploiting the measurement of the longitudinal, lateral and
temporal distribution of particles in air showers recorded at
the Pierre Auger Observatory. The results, obtained at about
10[sup]19 eV (E[inf]CM ∼ 140 TeV center-of-mass energy for
proton primaries), are compared to the predictions
of LHC-tuned hadronic interaction models with different primary
masses and suggest a deficit in the muon content at the
ground predicted by simulations. The Pierre Auger Observatory
uses water-Cherenkov detectors to measure particle
densities at the ground and therefore has a good
sensitivity to the muon content of air showers. Moreover, due
to its hybrid design, the combination of muon measurements with
other independent mass composition analyses such as Xmax
provides additional constraints on hadronic interaction models.
Keywords: Pierre Auger Observatory, ultra-high energy cosmic rays, muons, mass composition, hadronic interactions
Published in RUNG: 03.03.2016; Views: 4790; Downloads: 218
Full text (298,46 KB) |
299. Update of the neutrino and photon limits from the Pierre Auger ObservatoryCarla Bleve, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: Ultra-high energy neutrinos and photons, with energies above
1 EeV and 10 EeV respectively, can be detected with the Surface
Detector array (SD) of the Pierre Auger Observatory. Downward-
going neutrinos of all flavours interacting in the atmosphere
at zenith angles θ > 60◦, upward-going tau neutrinos (“Earth-
skimming”), as well as photons in the zenith range 30◦ − 60◦
can be identified through the broad time-structure of the
signals expected to be induced in the SD stations. An
additional signature for photon-induced air showers is the
steeper lateral distribution of secondary particles at ground
with respect to the nucleonic showers. Stringent limits are set
to the diffuse flux of ultra-high energy (UHE) neutrinos and
photons, using data collected between 2004 and mid-2013, under
the hypothesis of an E[sup]−2 spectrum for signal primaries.
Keywords: ultra-high energy neutrinos, ultra-high energy photons, cosmic rays, elemental composition, Pierre Auger Observatory
Published in RUNG: 03.03.2016; Views: 4883; Downloads: 231
Full text (398,21 KB) |
300. Composition at the “ankle” measured by the Pierre Auger Observatory: pure or mixed?Alexey Yushkov, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: We report for the first time on the measurement of the
correlation between the depth of shower maximum and the signal
in water-Cherenkov stations for events reconstructed by both
the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlated measurement is a unique feature
of a hybrid air-shower observatory and allows us to determine
the purity of the cosmic-ray composition. The observed
correlation in the energy range around the “ankle”
lg(E/eV) = 18.5−19.0 differs significantly from the expectations for pure beams, indicating that the primary composition in this range is mixed, unless the
hadronic interactions at these energies behave very
differently than in conventional, LHC-tuned event generators.
Keywords: ultra-high energy cosmic rays, elemental composition, depth of shower maximum, secondary cosmic rays, Pierre Auger Observatory
Published in RUNG: 02.03.2016; Views: 5320; Downloads: 238
Full text (388,00 KB) |
