A method to calibrate the absolute energy scale of air showers with ultra-high energy photons

Abstract

Calibrating the absolute energy scale of air showers initiated by ultra-high energy cosmic rays is an important experimental issue. Currently, the corresponding systematic uncertainty amounts to 14-21% using the fluorescence technique. Here we describe a new, independent method which can be applied if ultra-high energy photons are observed. While such photon-initiated showers have not yet been identified, the capabilities of present and future cosmic-ray detectors may allow their discovery. The method makes use of the geomagnetic conversion of UHE photons (preshower effect), which significantly affects the subsequent longitudinal shower development. The conversion probability depends on photon energy and can be calculated accurately by QED. The comparison of the observed fraction of converted photon events to the expected one allows the determination of the absolute energy scale of the observed photon air showers and, thus, an energy calibration of the air shower experiment. We provide details of the method and estimate the accuracy that can be reached as a function of the number of observed photon showers. Already a very small number of UHE photons may help to test and fix the absolute energy scale.

arXiv commentaccepted for publication in Phys. Rev. Lett

References in corpus (21)

• Monte Carlo treatment of hadronic interactions in enhanced Pomeron scheme: I. QGSJET-II model
• First Observation of the Greisen-Zatsepin-Kuzmin Suppression
• Observation of the suppression of the flux of cosmic rays above 4x10^19eV
• Measurement of the Depth of Maximum of Extensive Air Showers above 10^18 eV
• On astrophysical solution to ultra high energy cosmic rays
• Parton Ladder Splitting and the Rapidity Dependence of Transverse Momentum Spectra in Deuteron-Gold Collisions at RHIC
• One-dimensional Hybrid Approach to Extensive Air Shower Simulation
• Indications of Proton-Dominated Cosmic Ray Composition above 1.6 EeV
• The Cosmic Ray Energy Spectrum Observed with the Surface Detector of the Telescope Array Experiment
• Upper limit on the cosmic-ray photon flux above 10^19 eV using the surface detector of the Pierre Auger Observatory
• New facts about muon production in Extended Air Shower simulations
• Extragalactic propagation of ultrahigh energy cosmic-rays
• The Tunka-133 EAS Cherenkov light array: status of 2011
• Search for ultra-high energy photons using air showers
• Simulation of Ultra-High Energy Photon Propagation in the Geomagnetic Field
• Constraints on the flux of primary cosmic-ray photons at energies E > 10^18 eV from Yakutsk muon data
• Underground Muon Counters as a Tool for Composition Analyses
• Measurement of the cosmic ray energy spectrum using hybrid events of the Pierre Auger Observatory
• Estimate of the fraction of primary photons in the cosmic-ray flux at energies ~10^17 eV from the EAS-MSU experiment data
• Review of the Multimessenger Working Group at UHECR-2012
• Ultra High Energy Cosmic Rays Propagation and Spectrum