Cherenkov radio pulses from EeV neutrino interactions: the LPM effect

Abstract

We study the implications of the LPM effect for the Cherenkov radiation of EeV electromagnetic showers in the coherent radiowave regime for ice. We show that for showers above 100~PeV the electric field scales with shower energy but has a markedly narrower angular distribution than for lower energy showers. We give an electric field frequency and angular spectrum parameterization valid for showers having energy up to the EeV regime and discuss the implications for neutrino detectors based on arrays of radio antennas. Implications of the LPM effect for under water neutrino detectors in project are also briefly addressed.