Cosmic Ray Muons in the Standard Model of Fundamental Particles

Muons are one of the twelve fundamental particle types of matter, having relatively long free-particle lifetime. A muon decays into three other light particles (leptons) through action of the “weak” force, transmitted by the so-called “heavy photons” - bosons W+/W-. Muons are present in the secondary cosmic ray showers in the atmosphere and reach the sea level. By detecting the delay time between arrival of the muon and an appearance of the decay electron in our single scintillation detector, we measured the muon’s average lifetime at rest in the material of our detector. This compares well with the established value. From the lifetime, using the Standard Model of Fundamental Particles’ (SM) relations and an experimental value for masses of W boson MW and of the muon mμ, we calculated the universal weak and electric charges and the vacuum expectation value of the Higgs field. We measured the sea-level fluxes of both low-energy (below 140 MeV) and high-energy muons and found that they must be energy-independent in the lower part of their spectrum. We also found the shapes of the energy spectra of low-energy muons and of their decay electrons. We were unsuccessful in our attempt to measure the stopping power of muons in lead shielding