Telescope Array Experiment

Cosmic rays of energies 10$^{\mathrm{15}}$ to 10$^{\mathrm{20}}$ eV and beyond are believed to be charged nuclei of galactic and extragalactic origins that are accelerated by violent events in the Universe and which propagate through the galactic and extragalactic fields and photon backgrounds before they finally reach the Earth, where they can be observed using very large cosmic ray detectors. To understand cosmic ray origin and propagation mechanisms, physicists study cosmic ray energy spectrum, mass composition, and anisotropies of their arrival directions. In this presentation, we report on the recent progress of these measurements by the Telescope Array Experiment, the largest cosmic ray detector in the Northern hemisphere, that was built in Utah, which consists of large ground arrays of plastic scintillator counters overlooked by the fluorescence detectors.