Measuring neutrino mass with radioactive ions in a storage ring

TL;DR

This paper proposes a novel method to measure neutrino mass by analyzing beta decay electrons from radioactive ions in a storage ring, requiring precise control of ion momentum and high decay counts.

Contribution

It introduces a kinematic measurement technique for neutrino mass using ion beams and backward electron detection near the beta decay endpoint.

Findings

Requires ion momentum control better than 10^{-5}

Identifies low Q-value nuclei suitable for measurement

Needs at least 10^{18} decays for sensitivity

Abstract

We propose a method to measure the neutrino mass kinematically using beams of ions which undergo beta decay. The idea is to tune the ion beam momentum so that in most decays, the electron is forward moving with respect to the beam, and only in decays near the endpoint is the electron moving backwards. Then, by counting the backward moving electrons one can observe the effect of neutrino mass on the beta spectrum close to the endpoint. In order to reach sensitivities for $m_\nu < 0.2$ eV, it is necessary to control the ion momentum with a precision better than $\delta p/p < 10^{-5}$, identify suitable nuclei with low Q-values (in the few to ten keV range), and one must be able to observe at least O($10^{18}$) decays.