The Status of the MARE Experiment with 187Re and 163Ho Isotopes

Abstract

Neutrino oscillation experiments have proved that neutrinos are massive particles but the assessment of their absolute\ud mass scale is still an outstanding challenge in today particle physics and cosmology. The laboratory experiments dedicated\ud to effective electron-neutrino mass determination are the ones based on the study of single beta decay or electron\ud capture (EC) decay. Exploiting only on energy-momentum conservation, this kinematic measurement is the only one\ud which permits to estimate neutrino masses without theoretical assumptions on neutrino nature and it is truly modelindependent.\ud To date the most competitive isotopes for a calorimetric measurement of the neutrino mass are 187Re and 163Ho. While the first decays beta, the latter decays via electron capture, and both have a Q-value around 2.5 keV.\ud The measurement of 163Ho EC is an appealing alternative to the 187Re beta decay measurement because few nuclei are\ud needed and it is a self-calibrating measurement. In this context the MARE project, based on rhenium thermal detectors\ud has been born.\ud We report here the status of MARE in Milan with Rhenium and the activity concerning the production of radioactive\ud 163Ho isotope in the framework of MARE

Global Bayesian analysis of neutrino mass data

“…(24) is really nothing more than an effective quantity, however, an observable one 16. Alternative isotopes, such as rhenium as used by MARE[36], do not seem to be competitive.…”

Direct measurement of the mass difference of As72−Ge72 rules out AsZhuang1, Eronen2, Roubin3 et al. 2021Phys. Rev. C180601View full textAdd to dashboardCite

“…For β decays, the fraction of decay events that fall into an energy interval just below the end-point energy (Q β ) is proportional to Q −3 β ; while for electron capture (EC), the event rate proportionality is even steeper. This implies that isotopes with the lowest Q value are desirable [12]. 187 Re has been considered for its low Q value of 2.492 (30) stat (15) syst keV [13,14] and because it can be used as a bolometric detector [12,15].…”

“…This implies that isotopes with the lowest Q value are desirable [12]. 187 Re has been considered for its low Q value of 2.492 (30) stat (15) syst keV [13,14] and because it can be used as a bolometric detector [12,15]. MARE (Microcalorimeter Arrays for a Rhenium Experiment) is the corresponding long-term project carrying the expectations for the future direct neutrino mass measurements [12,15].…”

Constraints on the Active and Sterile Neutrino Masses from Beta-Ray Spectra: Past, Present and Future1

“…where is the mass-difference of the mother and daughter atoms and is the calorimetric energy [148] . The status of the MARE experiment with 187 Re and 163 Ho isotopes was reported at the TAUP 2013 conference [147]. The first array of MARE-1, containing 31 thermistors equipped with AgReO 4 , was assembled.…”