Improved Statistical Determination of Absolute Neutrino Masses via Radiative Emission of Neutrino Pairs from Atoms

Understand

The atomic transition from an excited state $|{\rm e}\rangle$ to the ground state $|{\rm g}\rangle$ by emitting a neutrino pair and a photon, i.e., $|{\rm e}\rangle \to |{\rm g}\rangle + |\gamma\rangle + |\nu^{}_i\rangle + |\bar{\nu}^{}_j\rangle$ with $i, j = 1, 2, 3$, has been proposed by Yoshimura and his collaborators as an alternative way to determine the absolute scale $m^{}_0$ of neutrino masses.

• More recently, a statistical analysis of the fine structure of the photon spectrum from this atomic process has been performed [N.
• Song {\it et al.}, Phys.\ Rev.\ D {\bf 93}, 013020 (2016)] to quantitatively examine the experimental requirements for a realistic determination of absolute neutrino masses.
• In this paper, we show how to improve the statistical analysis and demonstrate that the previously required detection time can be reduced by one order of magnitude for the case of a $3\sigma$ determination of $m_0^{} \sim 0.01~\text{eV}$ with an accuracy better than $10\%$.