224 research outputs found
Results of Dark Matter Searches with the MACRO Experiment
The results of dark matter searches with the MACRO experiment are reported.
In particular indirect searches for WIMP's and direct searches for supermassive
GUT magnetic monopoles are reported together with massive neutrino studies
through the measurement of the oscillation induced anomalies in the atmospheric
neutrino flux.Comment: Talk given at the 4th Int. Workshop for the Identification of Dark
Matter, York (UK) September 200
Latest results from the DAMPE space mission
The space-based DAMPE (DArk Matter Particle Explorer) particle detector has been taking data for more than 7 years since its successful launch in December 2015. Its main scientific goals include the indirect search for dark matter signatures in the cosmic lepton and gamma-ray spectra, the study of galactic cosmic rays up to energies of hundreds of TeV and studies on highenergy gamma ray astronomy. The measurement of galactic cosmic ray spectra are reported here, those being fundamental tools to investigate the mechanisms of acceleration at their sources and propagation through the interstellar medium. Results on proton and helium, which revealed new spectral features, are described. Ongoing analyses on the cosmic ray light, medium and heavy mass nuclei are outlined, together with studies of the so-called secondary cosmic rays. Latest results on gamma-ray astronomy and dark matter search will be also summarized
Charge Measurement of Cosmic Ray Nuclei with the Plastic Scintillator Detector of DAMPE
One of the main purposes of the DArk Matter Particle Explorer (DAMPE) is to
measure the cosmic ray nuclei up to several tens of TeV or beyond, whose origin
and propagation remains a hot topic in astrophysics. The Plastic Scintillator
Detector (PSD) on top of DAMPE is designed to measure the charges of cosmic ray
nuclei from H to Fe and serves as a veto detector for discriminating gamma-rays
from charged particles. We propose in this paper a charge reconstruction
procedure to optimize the PSD performance in charge measurement. Essentials of
our approach, including track finding, alignment of PSD, light attenuation
correction, quenching and equalization correction are described detailedly in
this paper after a brief description of the structure and operational principle
of the PSD. Our results show that the PSD works very well and almost all the
elements in cosmic rays from H to Fe are clearly identified in the charge
spectrum.Comment: 20 pages, 4 figure
The DAMPE experiment: first data from space
The DAMPE satellite has been successfully launched in orbit on December 2015. The science goals of the mission include the study of high energy cosmic ray electrons, photons, protons and nuclei in a wide energy range: 109 − 1014 eV. A report on the mission status will be presented, together with on-orbit detector performance and first data coming from space
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
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