Dark Matter searches with AMS02

International audienceThe Alpha Magnetic Spectrometer (AMS), to be installed on the International Space Station, will provide data on cosmic radiations in a large range of rigidity from 0.5 GV up to 2 TV. The main physics goals in the astroparticle domain are the anti- matter and the dark matter searches. Observations and cosmology indicate that the Universe may include a large amount of unknown Dark Matter. It should be composed of non baryonic Weakly Interacting Massive Particles (WIMP). A good WIMP candidate being the lightest SUSY particle in R-parity conserving models. AMS offers a unique opportunity to study simultaneously SUSY dark matter in three decay channels from the neutralino annihilation: e+, antiproton and gamma. The supersymmetric theory frame is considered together with alternative scenarios (extra dimensions). The expected flux sensitivities in 3 year exposure for the e+/e- ratio, antiproton and gamma yields as a function of energy are presented and compared to other direct and indirect searches

Optimization of multivariate analysis for IACT stereoscopic systems

Multivariate methods have been recently introduced and successfully applied for the discrimination of signal from background in the selection of genuine very-high energy gamma-ray events with the H.E.S.S. Imaging Atmospheric Cerenkov Telescope. The complementary performance of three independent reconstruction methods developed for the H.E.S.S. data analysis, namely Hillas, model and 3D-model suggests the optimization of their combination through the application of a resulting efficient multivariate estimator. In this work the boosted decision tree method is proposed leading to a significant increase in the signal over background ratio compared to the standard approaches. The improved sensitivity is also demonstrated through a comparative analysis of a set of benchmark astrophysical sources.Comment: 10 pages, 8 figures, 3 tables, accepted for publication in Astroparticle Physic

HESS-II expected performance in the tens of GeV

International audienceBy the end of 2009 the four-telescopes-HESS-system will be upgraded to HESS-II with a new telescope with a 600 m2 mirror area and a very high resolution camera. HESS-II will allow to lower the energy threshold from 100 GeV to about 30 GeV and enhance the HESS sensitivity. Therefore AGNs at higher redshift could be detected and searches for new classes of very high energy gamma-ray emitters (pulsars, microquasars, GRB, and dark matter candidates) will also be possible. The evaluation of the instrument performance is presented in term of sensitivity, energy and angular resolutions, based on Monte Carlo simulation, using a multivariate analysis

Improved sensitivity of H.E.S.S.-II through the fifth telescope focus system

The Imaging Atmospheric Cherenkov Telescope (IACT) works by imaging the very short flash of Cherenkov radiation generated by the cascade of relativistic charged particles produced when a TeV gamma ray strikes the atmosphere. This energetic air shower is initiated at an altitude of 10-30 km depending on the energy and the arrival direction of the primary gamma ray. Whether the best image of the shower is obtained by focusing the telescope at infinity and measuring the Cherenkov photon angles or focusing on the central region of the shower is a not obvious question. This is particularly true for large size IACT for which the depth of the field is much smaller. We address this issue in particular with the fifth telescope (CT5) of the High Energy Stereoscopic System (H.E.S.S.); a 28 m dish large size telescope recently entered in operation and sensitive to an energy threshold of tens of GeVs. CT5 is equipped with a focus system, its working principle and the expected effect of focusing depth on the telescope sensitivity at low energies (50-200 GeV) is discussed.Comment: In Proceedings of the 33rd International Cosmic Ray Conference (ICRC2013), Rio de Janeiro (Brazil

AMS02 Ecal gamma trigger performance measured at the October 2004 CERN test beam

Test beam data collected in October 2004 at CERN PS to validate the AMS02 Ecal Intermediate Board (EIB) are analyzed. After describing the experimental setup and the event samples, results concerning noise measurement, trigger efficiency and threshold accuracy are presented. They demonstrate that the EIB fulfils the physics requirements. Therefore the analog part of the trigger is validated, and hardware choices are also made towards the final device.Comment: 40 pages, 51 figures, AMS not

The electromagnetic calorimeter of the AMS-02 experiment

The electromagnetic calorimeter (ECAL) of the AMS-02 experiment is a 3-dimensional sampling calorimeter, made of lead and scintillating fibers. The detector allows for a high granularity, with 18 samplings in the longitudinal direction, and 72 sampling in the lateral direction. The ECAL primary goal is to measure the energy of cosmic rays up to few TeV, however, thanks to the fine grained structure, it can also provide the separation of positrons from protons, in the GeV to TeV region. A direct measurement of high energy photons with accurate energy and direction determination can also be provided.Comment: Proceedings of SF2A conference 201

Indirect search for dark matter with micrOMEGAs2.4

We present a new module of micrOMEGAs devoted to the computation of indirect signals from dark matter annihilation in any new model with a stable weakly interacting particle. The code provides the mass spectrum, cross-sections, relic density and exotic fluxes of gamma rays, positrons and antiprotons. The propagation of charged particles in the Galactic halo is handled with a new module that allows to easily modify the propagation parameters.Comment: 24 pages, 6 figures, typos corrected, acknowledgements modifie

The Minimal Supersymmetric Standard Model: Group Summary Report

CONTENTS: 1. Synopsis, 2. The MSSM Spectrum, 3. The Physical Parameters, 4. Higgs Boson Production and Decays, 5. SUSY Particle Production and Decays, 6. Experimental Bounds on SUSY Particle Masses, 7. References.Comment: 121 pages, latex + epsfig, graphicx, axodraw, Report of the MSSM working group for the Workshop "GDR-Supersym\'etrie",France. Rep. PM/98-4