Search for Majorana neutrinos exploiting millikelvin cryogenics with CUORE

TL;DR

This paper reports on the CUORE experiment's search for neutrinoless double beta decay of tellurium-130 at millikelvin temperatures, setting new lower bounds on decay half-life and demonstrating advanced cryogenic techniques.

Contribution

The study introduces innovative cryogenic calorimeters operating at millikelvin temperatures for large-scale neutrino decay searches, enhancing sensitivity and operational longevity.

Findings

No evidence for neutrinoless double beta decay was observed.

Set a lower bound on decay half-life at >2.2×10^{25} years.

Demonstrated advanced cryogenic technology with applications beyond neutrino physics.

Abstract

The possibility that neutrinos may be their own antiparticles, unique among the known fundamental particles, arises from the symmetric theory of fermions proposed by Ettore Majorana in 1937. Given the profound consequences of such Majorana neutrinos, among which is a potential explanation for the matter-antimatter asymmetry of the universe via leptogenesis, the Majorana nature of neutrinos commands intense experimental scrutiny globally; one of the primary experimental probes is neutrinoless double beta ($0 \nu \beta \beta$) decay. Here we show results from the search for $0 \nu \beta \beta$ decay of $^{130}$Te, using the latest advanced cryogenic calorimeters with the CUORE experiment. CUORE, operating just 10 millikelvin above absolute zero, has pushed the state of the art on three frontiers: the sheer mass held at such ultra-low temperatures, operational longevity, and the low levels of ionising radiation emanating from the cryogenic infrastructure. We find no evidence for $0 \nu \beta \beta$ decay and set a lower bound of $T_{1/2}^{0 \nu} > 2.2 \times 10^{25}$ years at a 90% credibility interval. We discuss potential applications of the advances made with CUORE to other fields such as direct dark matter, neutrino and nuclear physics searches and large-scale quantum computing, which can benefit from sustained operation of large payloads in a low-radioactivity, ultra-low temperature cryogenic environment.