FASER2

Abstract:

The Cherenkov Telescope Array (CTA) is a project for the construction of a next generation VHE gamma ray observatory with full sky coverage. Its aim is improving by about one order of magnitude the sensitivity of the existing installations, covering about 5 decades in energy (from few tens of GeV to above a hundred TeV) and having enhanced angular and energy resolutions. During 2010 the project became a truly global endeavour carried out by a consortium of about 750 collaborators from Europe, Asia, Africa and the North and South Americas. Also during 2010 the CTA project completed its Design Study phase and started a Preparatory Phase that is expected to extend for three years and should lead to the starting of the construction of CTA. An overview of the CTA Consortium activities project will be given.

Abstract:

We study the impact of the assumed velocity distribution of galactic dark matter particles on the interpretation of results from nuclear recoil detectors. By converting experimental data to variables that make the astrophysical unknowns explicit, different experiments can be compared without implicit assumptions concerning the dark matter halo. We extend this framework to include the annual modulation signal, as well as multiple target elements. Recent results from DAMA, CoGeNT and CRESST-II can be brought into agreement if the velocity distribution is very anisotropic and thus allows a large modulation fraction. However constraints from CDMS and XENON cannot be evaded by appealing to such astrophysical uncertainties alone.

Abstract:

We present a comprehensive study of the influence of the geomagnetic field on the energy estimation of extensive air showers with a zenith angle smaller than 60°, detected at the Pierre Auger Observatory. The geomagnetic field induces an azimuthal modulation of the estimated energy of cosmic rays up to the ∼ 2% level at large zenith angles. We present a method to account for this modulation of the reconstructed energy. We analyse the effect of the modulation on large scale anisotropy searches in the arrival direction distributions of cosmic rays. At a given energy, the geomagnetic effect is shown to induce a pseudo-dipolar pattern at the percent level in the declination distribution that needs to be accounted for. © 2011 IOP Publishing Ltd and SISSA.

Abstract:

Between 2009 May and 2010 May, the IceCube neutrino detector at the South Pole recorded 32 billion muons generated in air showers produced by cosmic rays with a median energy of 20TeV. With a data set of this size, it is possible to probe the southern sky for per-mil anisotropy on all angular scales in the arrival direction distribution of cosmic rays. Applying a power spectrum analysis to the relative intensity map of the cosmic ray flux in the southern hemisphere, we show that the arrival direction distribution is not isotropic, but shows significant structure on several angular scales. In addition to previously reported large-scale structure in the form of a strong dipole and quadrupole, the data show small-scale structure on scales between 15° and 30°. The skymap exhibits several localized regions of significant excess and deficit in cosmic ray intensity. The relative intensity of the smaller-scale structures is about a factor of five weaker than that of the dipole and quadrupole structure. The most significant structure, an excess localized at (right ascension α = 1224 and declination δ = -474), extends over at least 20° in right ascension and has a post-trials significance of 5.3σ. The origin of this anisotropy is still unknown. © 2011. The American Astronomical Society. All rights reserved.