A Parametrization of Cosmic Ray Shower Profiles Based on Shower Width

Abstract

Cosmic ray (CR) air showers, detected via the air fluorescence technique, are reconstructed in part using functions that parameterize the longitudinal profile of each shower. The profile parameterization yields the position of shower maximum, X_max, which is sensitive to the incident CR particle type: e.g. p, C/N/O, Fe or photons. The integral of the profile is directly related to the shower energy. The Pierre Auger fluorescence reconstruction uses the Gaisser-Hillas 4-parameter form. The HiRes group has used both the Gaisser-Hillas form and a 3-parameter Gaussian in Age form. Historically analytic shower theory suggested yet other forms; the best known is a 3-parameter form popularized by Greisen. Our work now uses the shower full width half-maximum, "fwhm", and shower asymmetry parameter, "f", to unify the parameterization of all three profile functions. Furthermore shower profiles expressed in terms of the new parameters: (fwhm, f) have correlations greatly reduced over Gaisser-Hillas parameters (X_0, lambda). This allows shower profile reconstructions to add constraints (if needed) on the mostly uncorrelated parameters (fwhm, f).

12 pages, 6 figures, to be published in J. Phys G: Nucl. & Part. Phys

References in corpus (2)

• Reconstruction of Longitudinal Profiles of Ultra-High Energy Cosmic Ray Showers from Fluorescence and Cherenkov Light Measurements
• First Results of Fast One-dimensional Hybrid Simulation of EAS Using CONEX

Cited by in corpus (7)

• Ultrahigh Energy Cosmic Rays
• Measurement of the average shape of longitudinal profiles of cosmic-ray air showers at the Pierre Auger Observatory
• Intermediate models for longitudinal profiles of cosmic showers
• A LOFAR-style reconstruction of cosmic-ray air showers with SKA-Low
• Macroscopic approach to the radar echo scatter from high-energy particle cascades
• Alternative description of particle shower longitudinal profile
• Air shower universality from 10^14 to 10^22 eV