Upper limit on the photon fraction in highest-energy cosmic rays from AGASA data

Abstract

A new method to derive an upper limit on photon primaries from small data sets of air showers is developed which accounts for shower properties varying with the primary energy and arrival direction. Applying this method to the highest-energy showers recorded by the AGASA experiment, an upper limit on the photon fraction of 51% (67%) at a confidence level of 90% (95%) for primary energies above 1.25 * 10^20 eV is set. This new limit on the photon fraction above the GZK cutoff energy constrains the Z-burst model of the origin of highest-energy cosmic rays.

arXiv comment4 pages, 3 figures. Analysis extended to account for primary energy resolution; conclusions unchanged. Accepted by Phys. Rev. Lett

References in corpus (26)

• Big Bang Nucleosynthesis (in "The Review of Particle Properties" 2004)
• Cosmic strings
• EGRET Observations of the Extragalactic Gamma Ray Emission
• Extension of the Cosmic-Ray Energy Spectrum Beyond the Predicted Greisen-Zatsepin-Kuz'min Cutoff
• Origin and Propagation of Extremely High Energy Cosmic Rays
• Detection of a Cosmic Ray with Measured Energy Well Beyond the Expected Spectral Cutoff due to Cosmic Microwave Radiation
• Small-scale anisotropy of cosmic rays above 10^19eV observed with the Akeno Giant Air Shower Array
• Ultra-high energy cosmic rays without GZK cutoff
• Energy determination in the Akeno Giant Air Shower Array experiment
• A new determination of the extragalactic diffuse gamma-ray background from EGRET data
• Measurement of the Flux of Ultrahigh Energy Cosmic Rays from Monocular Observations by the High Resolution Fly's Eye Experiment
• Extremely high energy cosmic rays from relic particle decays
• New constraints from Haverah Park data on the photon and iron fluxes of UHE cosmic rays
• The high energy cosmic ray spectrum from relic particle decay
• Hadronic scattering amplitudes: medium-energy constraints on asymptotic behaviour
• Ultra-High Energy Neutrino Fluxes: New Constraints and Implications
• Caltech Faint Galaxy Redshift Survey XIV: Galaxy Morphology in the HDF (North) and its Flanking Fields to z=1.2
• Fragmentation functions in SUSY QCD and UHECR spectra produced in top-down models
• Constraints on the Ultra High Energy Photon flux using inclined showers from the Haverah Park array
• New data and the hard pomeron
• The spectrum features of UHECRs below and surrounding GZK
• Ultra-High Energy Cosmic Rays: A Probe of Physics and Astrophysics at Extreme Energies
• Detailed analysis of the decay spectrum of a super-heavy X particle
• Grand Unification Signal from Ultra High Energy Cosmic Rays?
• The highest-energy cosmic rays
• Primary Particle Type of the Most Energetic Fly's Eye Air Shower

Cited by in corpus (37)

• Cosmic Rays from the Knee to the Highest Energies
• Upper limit on the cosmic-ray photon flux above 10^19 eV using the surface detector of the Pierre Auger Observatory
• Upper limit on the cosmic-ray photon fraction at EeV energies from the Pierre Auger Observatory
• Lorentz Violation for Photons and Ultra-High Energy Cosmic Rays
• An upper limit to the photon fraction in cosmic rays above 10^19 eV from the Pierre Auger Observatory
• Search for ultra-high energy photons using air showers
• Constraints on the diffuse photon flux with energies above $10^{18}$ eV using the surface detector of the Telescope Array experiment
• Upper limit on the ultra-high-energy photon flux from AGASA and Yakutsk data
• Upper limit on the flux of photons with energies above 10^19 eV using the Telescope Array surface detector
• Constraints on the flux of primary cosmic-ray photons at energies E > 10^18 eV from Yakutsk muon data
• Cosmic Ray Astronomy
• On the status of superheavy dark matter
• UHECR Particle Spectra from Crypton Decays
• Constraining the fraction of primary gamma rays at ultra-high energies from the muon data of the Yakutsk extensive-air-shower array
• Sensitivity of cosmic-ray experiments to ultra-high-energy photons: reconstruction of the spectrum and limits on the superheavy dark matter
• Prospective constraints on Lorentz violation from ultrahigh-energy photon detection
• Limits on Neutron Lorentz Violation from the Stability of Primary Cosmic Ray Protons
• GZK Photons Above 10 EeV
• Super Heavy Dark Matter and UHECR Anisotropy at Low Energy
• Non-Universal Spectra of Ultra-High Energy Cosmic Ray Primaries and Secondaries in a Structured Universe
• Characteristics of geomagnetic cascading of ultra-high energy photons at the southern and northern sites 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
• Photon air showers at ultra-high energy and the photonuclear cross-section
• A Faraway Quasar in the Direction of the Highest Energy Auger Event
• Towards event-by-event studies of the ultrahigh-energy cosmic-ray composition
• Review of the Multimessenger Working Group at UHECR-2012
• Search for point sources of ultra-high energy photons with the Telescope Array surface detector
• Pierre Auger Data, Photons, and Top-Down Cosmic Ray Models
• Acceptance of fluorescence detectors and its implication in energy spectrum inference at the highest energies
• Deep shower interpretation of the cosmic ray events observed in excess of the Greisen-Zatsepin-Kuzmin energy
• Search for cosmic gamma rays with the Carpet-2 extensive air shower array
• Observations of Ultra-High Energy Cosmic Rays
• Astronomy with ultra high-energy particles
• Energy reconstruction of hadron-initiated showers of ultra-high energy cosmic rays
• Extreme high energy proton-gamma discrimination from space observations
• GZK photons as UHECR above 10${}^{19}$ eV
• Cosmic Rays at the Highest Energies -- First Data from the Pierre Auger Observatory --