12-20 July 2017
Asia/Seoul timezone
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BEXCO - Room B(103/104/105)

[CRI263] CR Primary Mass Identification with Lateral Muon Profile of EAS


  • Moon Moon DEVI

Primary authors



The measurement of the individual charged particles in an extensive air shower (EAS), at a surface detector array, provides important distinguishing parameters to identify the cosmic primary mass spectrum. These will also contribute to the mapping of the very high energy interactions in the topmost layers of the atmosphere, i.e., beyond the reach of current accelerators, and to probe anomalies beyond QCD. The direct detectors placed in balloons or satellites and can probe the composition of cosmic primaries with energy up to about $10^{14.5}$ eV only. The ongoing attempts to study individual muons are limited in their expandability to larger arrays. New developments in detector technology allow for a realistic cost of large area detectors, however with limitations on energy resolutions, directional information and dynamic range. We performed a simulation study using CORSIKA to combine the lateral profile of the muons, characterized by their energy spectrum and lateral spread, with the depth at shower maximum (Xmax) of an EAS initiated by a primary at ultra high energies ($10^{16}$ eV -- $10^{19}$ eV). Using proton and iron as the shower primaries, we show that the muon observables and Xmax together can be used in a likelihood test to identify the primary. We further probe the effect of the hadronic uncertainties on the primary-separation potential of the observables in detail by testing it against different hadron interaction models. This study is then extended to three groups of primaries, light ($Z leq 2$), medium ($3 leq Z leq 11$) and heavy ($12 leq Z leq 26$). This study can be used to design a future muon detector for surface array, which will be able to enhance our knowledge of primaries and QCD interactions.