SNOLAB hosts 2nd International Summit on the Future of Neutrinoless Double Beta Decay

May 02, 2023 — Events

Emerging field of study could bring major new physics experiments to SNOLAB

SUDBURY: A select group of more than 60 of the world’s leading particle physicists and representatives from science funding bodies gathered at SNOLAB last week to map out the future of an emerging field of study that could revise the Standard Model of Physics and dramatically advance our understanding of physics and the cosmos.

“The search for neutrinoless double beta decay is one of the most compelling and exciting challenges in contemporary physics”, says SNOLAB Executive Director Dr. Jodi Cooley. It is a hypothetical radioactive process which, if observed, would prove the neutrino to be a Majorana fermion: a particle that is its own antiparticle.

The purpose of the 2nd International Summit on the Future of Neutrinoless Double Beta Decay, hosted by SNOLAB on April 27 and 28, was to bring together stakeholders in the international particle physics community to continue discussions on the strategy and a path to progress in this scientific priority.

“Tonne-scale neutrinoless double beta decay experiments have been a priority of the international particle physics community for several years,” Dr. Cooley said.

“With this two-day summit completed, we have agreed to continue our efforts to pursue this exciting field of study, and SNOLAB is well positioned to play a significant role,” Cooley said.

Two large international collaborations proposing tonne-scale experiments—nEXO and LEGEND- 1000—presented to the summit. Both promise unprecedented sensitivity to neutrinoless double beta decays, and both are looking for a home.

SNOLAB has been identified by both collaborations as their baseline location and, provided the commitment of the international particle physics community continues apace, SNOLAB will almost certainly host at least one of them, Cooley said.

A third experiment, CUPID, is already being planned for Laboratori Nazionali del Gran Sasso in Italy.

“SNOLAB’s low background environment is ideal for the study of extremely rare physical interactions. And SNOLAB’s experience hosting and supporting large-scale experiments make us a location of choice for projects such as these,” Cooley said.

Both collaborations would involve hundreds of scientists, technologists, and engineers from dozens of institutions around the world. And either large-scale experiment would mean a $400-million-plus investment at SNOLAB.

“A decision on how to proceed with these large experiments—and where—is still a year or more away,” Cooley said, “while commissioning of these experiments would be several years away”.

About neutrinoless double beta decay:

Neutrinos—tiny, nearly massless particles with no charge—are difficult to detect and measure, but they may hold the answers to unanswered cosmic questions. To understand more about the neutrino, particle physicists are searching for an extremely rare (and still hypothesized) version of double beta decay.

Double beta decay is a process whereby a nucleus decays into another one and emits two electrons and two antineutrinos. A special version of double beta decay—the “neutrinoless” version—emits only two electrons and no antineutrinos.

Neutrinoless double beta decay is at the boundary of human knowledge since it has not yet been observed and cannot occur according to the laws of physics as we know them. Detecting this process would thus revise the Standard Model of Physics and dramatically advance our understanding of physics and the cosmos.


SNOLAB is Canada’s deep underground research laboratory, located in Vale’s Creighton mine near Sudbury, Ontario Canada. It provides an ideal low background environment for the study of extremely rare physical interactions. SNOLAB’s science program focuses on astroparticle physics, specifically neutrino and dark matter studies, though its unique location is also well-suited to biology and geology experiments. SNOLAB facilitates world-class research, trains highly qualified personnel, and inspires the next generation of scientists.

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