Can we use heavy nuclei to detect relic neutrinos?

TL;DR

This paper explores the potential of using heavy nuclei, specifically $^{171}$Tm and $^{151}$Sm, as targets for relic neutrino detection, proposing an experimental method to determine their neutrino capture cross-sections.

Contribution

It introduces a novel experimental approach to measure the neutrino capture cross-section from the beta spectrum of heavy isotopes, addressing a key missing piece for relic neutrino detection.

Findings

Identifies $^{171}$Tm and $^{151}$Sm as promising neutrino target isotopes.

Proposes a method to extract neutrino capture cross-section from beta spectra.

Addresses the challenge of linking isotope half-life to neutrino capture rate.

Abstract

Recent analysis of the viability of solid state-based relic neutrino detectors has revealed the fundamental necessity for the use of heavy, $A>100$, $\beta$-decayers as neutrino targets. Of all heavy isotopes, $^{171}$Tm and $^{151}$Sm stand out for their sufficiently low decay energies, reasonable half-life times and stable daughter nuclei. However, the crucial bit of information, that is the soft neutrino capture cross-section is missing for both isotopes. The main reason for that is a particular type of $\beta$-decay, which precludes a simple link between the isotope's half-life time and the neutrino capture rate. Here we propose an experimental method to bypass this difficulty and obtain the capture cross-section of a soft neutrino by a given isotope from the isotope's $\beta$-spectrum.