The charge ratio of the atmospheric muons at low energy

Abstract

From the nature of the muon production processes, it can be seen that the ratio of positive to negative cosmic muons has important information in both ``the atmospheric neutrino problem,'' and ``the hadronic interactions.'' We have carried out an experiment for the measurement of the muon charge ratio in the cosmic ray flux in momentum range $0.112--0.178\text{ }\text{ }\mathrm{GeV}/\mathrm{c}$. The muon charge ratio is found to be $1.21\ifmmode\pm\else\textpm\fi{}0.01$ with a mean zenith angle of $32\ifmmode^\circ\else\textdegree\fi{}\ifmmode\pm\else\textpm\fi{}5\ifmmode^\circ\else\textdegree\fi{}$. From the measurements it has been obtained a zenithal angle distribution of muons as $I(\ensuremath{\theta})=I(0){cos}^{n}\ensuremath{\theta}$ with $n=1.95\ifmmode\pm\else\textpm\fi{}0.13$. An asymmetry has been observed in East-West directions because of the geomagnetic field. Meanwhile, in about the same momentum range, positive and negative muons have been studied on the basis of Monte Carlo simulations of the extensive air shower developement (Cosmic Ray Simulations for Kascade), using the Quark Gluon String model with JETs model as generator.