Relic neutrinos at accelerator experiments

TL;DR

This paper proposes a novel method using ion storage rings to detect cosmic neutrino background by exploiting resonant neutrino capture, but current technology is insufficient for discovery.

Contribution

It introduces a new technique utilizing ion storage rings and resonant processes to enhance low-energy neutrino detection capabilities.

Findings

Resonant neutrino capture can increase cross sections at lower energies.

Optimal experimental parameters are calculated for various ion systems.

Current technology cannot achieve sufficient detection statistics.

Abstract

We present a new technique for observing low energy neutrinos with the aim of detecting the cosmic neutrino background using ion storage rings. Utilising high energy targets exploits the quadratic increase in the neutrino capture cross section with beam energy, and with sufficient beam energy, enables neutrino capture through inverse-beta decay processes from a stable initial state. We also show that there exist ion systems admitting resonant neutrino capture, capable of achieving larger capture cross sections at lower beam energies than their non-resonant counterparts. We calculate the neutrino capture rate and the optimal experimental runtime for a range of different resonant processes and target ions and we demonstrate that the resonant capture experiment can be performed with beam energies as low as $\mathcal{O}(10\,\mathrm{TeV})$ per target nucleon. Unfortunately, none of the ion systems discussed here can provide sufficient statistics to discover the cosmic neutrino background with current technology. We address the challenges associated with realising this experiment in the future, taking into account the uncertainty in the beam and neutrino momentum distributions, synchrotron radiation, as well as the beam stability.