HOLMES - The Electron Capture Decay of 163Ho to Measure the Electron Neutrino Mass with sub-eV sensitivity

TL;DR

HOLMES is a calorimetric experiment designed to measure the electron neutrino mass with sub-eV sensitivity by analyzing the decay of 163Ho, representing a significant advancement in direct neutrino mass measurement techniques.

Contribution

The paper introduces the HOLMES experiment, utilizing advanced microcalorimeters for direct neutrino mass measurement, achieving unprecedented sensitivity and demonstrating the potential of calorimetric methods.

Findings

Mass sensitivity as low as 0.4 eV

Potential to extend sensitivity down to 0.1 eV

First implementation of large array low-temperature microcalorimeters for neutrino mass measurement

Abstract

The European Research Council has recently funded HOLMES, a new experiment to directly measure the neutrino mass. HOLMES will perform a calorimetric measurement of the energy released in the decay of 163Ho. The calorimetric measurement eliminates systematic uncertainties arising from the use of external beta sources, as in experiments with beta spectrometers. This measurement was proposed in 1982 by A. De Rujula and M. Lusignoli, but only recently the detector technological progress allowed to design a sensitive experiment. HOLMES will deploy a large array of low temperature microcalorimeters with implanted 163Ho nuclei. The resulting mass sensitivity will be as low as 0.4 eV. HOLMES will be an important step forward in the direct neutrino mass measurement with a calorimetric approach as an alternative to spectrometry. It will also establish the potential of this approach to extend the sensitivity down to 0.1 eV. We outline here the project with its technical challenges and perspectives.