ar X iv : a st ro - p h / 02 12 48 1 v 1 2 0 D ec 2 00 2 Energy Spectrum and Mass Composition around the Knee by EAS Measurements ‡
نویسنده
چکیده
Primary cosmic ray particles above energies of about 100 TeV are investigated by large-area ground based detector installations, observing various components of the development of extensive air-showers (EAS). By such an indirect access to the primary cosmic ray spectrum a steepening of the power-law falls off at around 3-5 PeV, known as the knee has been identified. Different experimental techniques are used to deduce mass-and energy-sensitive observables of EAS experiments. The experiments involve measurements of secondary particle distributions at various observation levels and of muons deep underground as well as of observables reconstructed by measuring the air Cherenkov light emitted with the shower development in the atmosphere. Recently methods for analysing multidimensional distributions get favoured since they are able to take into account the correlations between different observables and the influence of large intrinsic fluctuations of the air-shower development. Additionally the use of a larger set of observables provides the possibility to test simultaneously the consistency of the Monte-Carlo models underlying the reconstruction procedures. By many experiments the existence of the knee in the primary energy spectrum is confirmed and a tendency of an increasing mean mass above the knee energy is indicated. Recent results show that the knee originates from a decrease of the flux of light primary particles, whereas heavy cosmic ray particles seem to miss a kink in the energy range of 1 and 10 PeV.
منابع مشابه
ar X iv : a st ro - p h / 02 12 56 6 v 1 3 0 D ec 2 00 2 Dark Energy : Is it Q or Λ ?
New observations of Cosmic Microwave Background Anisotropies, Su-pernovae luminosity distances and Galaxy Clustering are sharpening our knowledge about dark energy. Here we present the latest constraints.
متن کاملar X iv : a st ro - p h / 02 11 45 7 v 2 1 0 D ec 2 00 2 Time variation of fundamental constants : two phenomenological models
Time variation of fundamental constants, a strong signal of new physics, is analyzed comparing extant data with two phenomenological models. Results are discussed.
متن کاملar X iv : a st ro - p h / 07 02 37 0 v 2 5 J un 2 00 7 Cosmic - ray composition and its relation to shock acceleration by supernova remnants ⋆
An overview is given on the present status of the understanding of the origin of galactic cosmic rays. Recent measurements of charged cosmic rays and photons are reviewed. Their impact on the contemporary knowledge about the sources and acceleration mechanisms of cosmic rays and their propagation through the Galaxy is discussed. Possible reasons for the knee in the energy spectrum and scenarios...
متن کاملar X iv : a st ro - p h / 06 12 37 8 v 1 1 4 D ec 2 00 6 Magnetic fields , strings and cosmology
متن کامل
ar X iv : a st ro - p h / 01 12 42 3 v 1 1 8 D ec 2 00 1 The black hole mass of BL Lacs from stellar velocity dispersion of the host galaxy
The black hole mass of BL Lacs from stellar velocity dispersion of the host galaxy.
متن کامل