Momentum Spectrum of Cosmic Muons at a Depth of 320 Mwe

Since their discovery, great progress has been achieved in the field of cosmic ray physics particularly towards the understanding of the origin, transport and acceleration mechanisms of the high energy particles that constitute primary cosmic rays, their interaction processes in the galactic and extra galactic media, and also in the Earth's atmosphere. The interaction of primary cosmic ray particles in the Earth's atmosphere leads to the production of a cascade of secondary particles or Extensive Air Showers (EAS) with various components - electromagnetic, hadronic, muon and neutrino components. There is a large number of models to describe these interactions. Many cosmic ray experiments have used a variety of observables in EAS that provide an understanding of the hadronic interactions and also shed some light on the chemical composition of the primary particles. The muon flux at the surface provides a useful tool for the calculations of neutrino fluxes, the reconstruction of EAS and it can serve as a test of various interaction models. The CosmoALEPH detector, whichwas one of the experiments in CosmoLEP used the ALEPH detector at the European Laboratory for Particle Physics, CERN, to measure the muonic component of EAS. Preliminary results have recently shown that the momentum spectrum and charge ratio for cosmic muons measured by CosmoALEPH are well within the world average. This work reports on further improvements in the reconstruction of the cosmic muon events and data analysis. Cosmic muons are produced through interactions of primary cosmic radiation in the atmosphere. They are a component of extensive air showers which can also be measured underground. The CosmoALEPH experiment used the ALEPH detector at the European Laboratory for Particle Physics, CERN, to measure cosmic muon events at a depth of 320 mwe underground. The momentum spectrum and charge ratio of the cosmic muons are measured. The results are compared with the expectations from MC simulations based on different hadronic interaction models.