Studies of Direct Cherenkov Emission with VERITAS

Ground-based composition measurements of high-energy cosmic rays can be significantly improved by using the direct Cherenkov method. This technique targets the Cherenkov light produced by the primary particle prior to its production of an extensive air shower. With the appropriate time and angular resolution, the direct Cherenkov photons can be separated from those produced in the extensiveair shower. By utilizing the 0.15 degree angular and 2 nanosecond timing resolution of the very high energy gamma-ray telescope system, VERITAS, the charge and energy of cosmic rays at TeV energies can be identified on an event-by-event basis. Results from a preliminary search for direct Cherenkov events are discussed.