From direct observations of the longitudinal development of ultrahigh energy air showers performed with the Pierre Auger Observatory, upper limits of fraction of cosmic ray photons. The results complement previous constraints on top–down models from array data and they reduce systematic uncertainties in the interpretation of shower data in terms of primary flux, nuclear composition and proton air cross section.
COBISS.SI-ID: 1144059
We report a measurement of the proton air cross section for particle production at the center of mass energy per nucleon of 57 TeV. This is derived from the distribution of the depths of shower maxima observed with the Pierre Auger Observatory: systematic uncertainties are studied in detail. Analyzing the tail of the distribution of the shower maxima, a protonair cross section of [505±22(stat)36+28(syst)] mb is found.
COBISS.SI-ID: 2468347
We describe the measurement of the depth of maximum of the longitudinal development of air showers induced by cosmic rays. Almost four thousand events above 10^18 eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The interpretation of the results in terms of the cosmic ray mass composition is briefly discussed.
COBISS.SI-ID: 1400315
We report the results of a high statistics search for H di-baryon production in inclusive Υ(1S) and Υ(2S) decays. No indication of an H di-baryon with a mass near the M_H=2m_Λ threshold is seen in either the H) Lambda p pi or Lambda-Lambda decay channels and 90% confidence level. Since Y(1,2S) decays produce flavor SU(3) symmetric final states, these results put stringent constraints on H di-baryon properties. The results are based on analyses of 102 million Y(1S) and 158 million Y(2S) events collected with the Belle detector at the KEKB electron-positron collider.
COBISS.SI-ID: 27039015
Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 510 improvement in sensitivity in the 100 GeV10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.
COBISS.SI-ID: 3234555