Studying High pT Muons in Cosmic-Ray Air Showers

Most cosmic-ray air shower arrays have focused on detecting electromagnetic shower particles and low energy muons. A few groups (most notably MACRO + EASTOP and SPASE + AMANDA) have studied the high energy muon component of showers. However, these experiments had small solid angles, and did not study muons far from the core. The IceTop + IceCube combination, with its 1 km2 muon detection area can study muons far from the shower core. IceCube can measure their energy loss (dE/dx), and hence their energy. With the energy, and the known distribution of production heights, the transverse momentum (pT) spectrum of high pT muons can be determined. The production of these muons is calculable in perturbative QCD, so the measured muon spectra can be used to probe the composition of incident cosmic-rays.