Improved statistical determination of absolute neutrino masses via radiative emission of neutrino pairs from atoms

Abstract

The atomic transition from an excited state |e to the ground state |g by emitting a neutrino pair and a photon, i.e., |e → |g + |γ + |ν i + |ν j 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 et al., Phys. Rev. D 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 3σ determination of m 0 ∼ 0.01 eV with an accuracy better than 10%. Such an improvement is very encouraging for further investigations on measuring absolute neutrino masses through atomic processes.

Testing unitarity of the 3 × 3 neutrino mixing matrix in an atomic system

“…It is clear that the emissions of ν 1 + ν 2 , ν 2 + ν 1 and ν 3 + ν 3 dominate the total spectrum, and this observation has already been noticed in Ref. [35]. Such a result can be obtained for two simple reasons: (i) the contributions from ν 1 + ν 3 (or ν 3 + ν 1 ) and ν 2 + ν 3 (or ν 3 + ν 2 ) are suppressed by the smallness of |V e3 |, as shown in Eq.…”

“…(3). An external laser with the frequency ω can be used to trigger the transition, and the result for its rate can be factorized into the expression [33][34][35]…”

“…After m 1 is measured, all the thresholds ω ij can then be located in the photon spectrum by inputting the known values of ∆m 2 21 and ∆m 2 31 . On the other hand, the approximate locations of the thresholds might be directly determined by a rough scanning of the kink structure of the photon spectrum [35]. To resolve the gap between any two different categories of ω ij , the precision of the laser frequency should be better than the energy gap ∼ 10 −3 eV.…”

“…The vertical dash-dotted lines signify all the thresholds in the spectrum function. and [35] to define the rate normalization factor…”

Probing cosmic axions through resonant emission and absorption in atomic systems with superradiance

“…Compared to the intensity of photons from stochastic emission, the SR intensity will be proportional to the square of the radiant number N 2 rather than N ∼ O(10 23 ), due to the interference among different radiants. The idea of using SR to magnify the atomic transition rate was originally introduced to determine neutrino properties with the radiative emission of a neutrino pair [39][40][41][42][43][44][45][46][47]. The emission rate of neutrino pairs can reach O(1) s −1 by using the trigger laser to irradiate the signal mode in a cm-scale atomic target, which should be very challenging for a realistic detection.…”