East West Asymmetry of Cosmic Rays*

Cosmic rays are, in essence, streams of high energy protons traveling through space. Being positively charged particles, they experience eastward deflection by the Lorentz force when they pass through Earth’s magnetic field. When the protons interact with Earth’s atmosphere they decay into kaons, and pions, which further decay into muons that inherit this deflection as they reach Earth’s surface. According to a simple model, more muons would be traveling eastwards, rather than westward, creating an asymmetry in their flux at Earth’s surface.  One of the purposes of this experiment was to observe and investigate this asymmetry using muon telescopes. As each of the telescopes have a unique setting for optimal efficiency, we needed to point them in both east and west directions to measure the asymmetry.  Our measurements from one telescope is inconclusive, and another suggests that the flux is greater from a westwards direction. We discuss our results.