2,629 research outputs found
Detection of anisotropies in the arrival directions of 600 GeVâ10TeV cosmic rays with the ARGO-YBJ experiment
ARGO-YBJ is an RPC âcarpetâ aimed to the detection of extensive air showers induced by charged cosmic rays and gamma-rays in the energy range GeVâPeV. The data-set collected since November 2007 has been analyzed and very
significant anisotropies (more than 10 standard deviations), with relative intensity of the order of 10â3 have been found. The observation is not explained with the
current models of galactic magnetic field and propagation of cosmic rays in the Galaxy
A needlet-based approach to the shower-mode data analysis in the ARGO-YBJ experiment
The ARGO-YBJ experiment, located at the Yangbajing Cosmic Ray Laboratory (Tibet, 4300 m a.s.l., 606 g/cm2), is an EAS-array exploiting the full coverage approach at high altitude. The large field of view (2 sr) and the low energy threshold (few hundreds of GeV) result in a trigger rate of âŒ3.5kHz and âŒ1011EAS collected per year. Such a data set contains signals laying on different angular scales: point-like and extended gamma-ray sources, as well as large and intermediate scale cosmic-ray anisotropies. The separation of all these contributions is crucial, mostly when they overlap with each other. Needlets are a new form of spherical wavelets that have recently drawn a lot of attention in the cosmological literature, especially in connection with the analysis of CMB data. Needlets enjoy a number of important statistical and numerical properties which suggest that they can be very effective in handling cosmic-ray and gamma-ray data analysis. An unprecedented application to astroparticle physics is shown here. In particular, we focus on their use for background estimation, which is expected to be optimal or nearly-optimal in a well-defined mathematical sense, and for point-source detection. This technique is applied here to the ARGO-YBJ data set, stressing its advantages with respect to standard methods
Updates on long-term alignment monitoring and diagnostics for ATLAS ID misalignments
This work deals with the alignment of ID tracker modules of the ATLAS experiment at the LH
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