Low-energy muons in extensive air showers at 800 g cm^-2

Abstract

The following results on the low-energy (> 0.6 GeV and > 1.0 GeV) muons in air showers of size 10⁵ to 2 × 10⁷ at Ootacamund (800 g cm^-2) are obtained: (1) The average total number of muons N μ varies as N_e^{0.32 ± 0.2} for 10⁵ < N_e < 10⁶, and as N_e ^{0.8 ± 0.15}for 10⁶ < N_e < 2 × 10⁷. (2) In showers showing flat electron lateral structure, the N μ variation with N_e is similar to (1). However, in steep showers, N μ varies as N_e ^{0.75 ± 0.15} in the whole size range 10⁵ to 2 × 10⁷. (3) "Muon-rich" showers of size < 10⁶ have less energy in the electron-photon component compared to "normal" showers. No such difference is found for showers of size > 10⁶. (4) There is a slight indication of a deficiency of muon-rich showers having a flat lateral distribution of electrons in the right ascension interval 15-21 hours for showers of size 10⁶-10⁷. A similar deficit of showers was observed by the Tokyo group for muon-rich showers in the same RA interval.