Askaryan radiation from neutrino-induced showers in ice

Abstract

We present a semi-analytical method for the calculation of coherent Askaryan radiation in showers induced by neutrinos of any flavor in ice. We compare our results with those of a full Monte Carlo simulation based on the ZHAireS code. This approach is able to reproduce the vector potential and hence electric field at any experimentally relevant observer position in the time domain. This work extends published results only valid for electron-induced showers. We establish the validity of the semi-analytical calculation of the radio signal produced by all types of neutrino-induced showers in ice. The method is computationally efficient and only requires as inputs the longitudinal charge excess profile of the showers and a parameterization of the vector potential in the far-field region of the shower at the Cherenkov angle that we also provide. Our methodology avoids tracking the contributions to the electric field from millions of particles every time the radio pulse has to be calculated at a given observer position. These results can be readily used in the interpretation of the data taken by experiments, and in the planning and design of future initiatives based on the radio technique in ice.