Improved flux limits for neutrinos with energies above 10$^{22}$ eV from observations with the Westerbork Synthesis Radio Telescope

TL;DR

This study used the Westerbork Synthesis Radio Telescope to observe lunar particle cascades caused by ultra-high energy neutrinos, setting new flux limits above 4×10^{22} eV.

Contribution

First to utilize the Westerbork Synthesis Radio Telescope for setting flux limits on ultra-high energy neutrinos via lunar Askaryan effect observations.

Findings

Set new upper limits on neutrino flux above 4×10^{22} eV

Demonstrated effectiveness of radio telescopes in UHE neutrino detection

Extended constraints on UHE neutrino models

Abstract

Particle cascades initiated by ultra-high energy (UHE) neutrinos in the lunar regolith will emit an electromagnetic pulse with a time duration of the order of nano seconds through a process known as the Askaryan effect. It has been shown that in an observing window around 150 MHz there is a maximum chance for detecting this radiation with radio telescopes commonly used in astronomy. In 50 hours of observation time with the Westerbork Synthesis Radio Telescope array we have set a new limit on the flux of neutrinos, summed over all flavors, with energies in excess of $4\times10^{22}$ eV.