The Directional Dependence of Apertures, Limits and Sensitivity of the Lunar Cherenkov Technique to a UHE Neutrino Flux

TL;DR

This paper uses simulations to analyze how the lunar Cherenkov technique's sensitivity to ultra-high energy neutrinos varies with direction, impacting current and future experiment limits and exposures.

Contribution

It provides a detailed analysis of the directional dependence of the lunar Cherenkov technique for UHE neutrino detection, including current and future experiments.

Findings

Effective area varies with neutrino arrival direction.

Current experiments impose direction-dependent limits.

Future experiments' exposure depends on celestial position.

Abstract

We use computer simulations to obtain the directional-dependence of the lunar Cherenkov technique for ultra-high energy (UHE) neutrino detection. We calculate the instantaneous effective area of past lunar Cherenkov experiments as a function of neutrino arrival direction, and hence the directional-dependence of the combined limit imposed by GLUE and the experiment at Parkes. We also determine the directional dependence of the aperture of future planned experiments with ATCA, ASKAP and the SKA to a UHE neutrino flux, and calculate the potential annual exposure to astronomical objects as a function of angular distance from the lunar trajectory through celestial coordinates.