Inverse Tritium Beta Decay with Relic Neutrinos, Solar Neutrinos, and a 51Cr Source

TL;DR

This paper explores the potential of using an intense $^{51}$Cr neutrino source and solar neutrinos to observe inverse tritium beta decay, aiming to detect relic neutrinos and analyze their properties.

Contribution

It proposes using a $^{51}$Cr radioactive source for the first time to observe ITBD and examines the reaction rate from solar and relic neutrinos considering neutrino properties.

Findings

$^{51}$Cr source can induce observable ITBD reactions.

Reaction rates depend on neutrino mass hierarchy and nature.

Relic neutrino capture rates vary with neutrino properties.

Abstract

The inverse tritium beta decay (ITBD) reaction, $\nu_e + ^3$H $\to e^- + ^3$He, is a promising experimental tool for observing relic neutrinos created in the early Universe. This reaction has been selected by the PTOLEMY experiment for the search of relic neutrinos. Despite its potential, the ITBD reaction induced by any sources of neutrinos has yet to be observed. We show that an intense $^{51}$Cr radioactive neutrino source is suitable for observing the ITBD reaction for the first time. As the Sun is another source of intense electron neutrinos, we also examine the ITBD reaction rate from solar neutrinos. Based on our recent studies on the evolution of the helicity of relic neutrinos, we further present the ITBD rate for capturing relic neutrinos as a function of neutrino mass hierarchy, the Dirac versus Majorana nature of neutrino, and the mass of the lightest neutrino.