CUORE

An observation of neutrinoless double beta decay would conclusively show that neutrinos are Majorana fermions; that is, they are their own antiparticles. This is relevant to many topics in particle physics, including lepton number conservation, nuclear structure, and neutrino masses and properties.
The CUORE collaboration involves physicists from several countries, primarily from the United States and Italy. CUORE is funded by the Istituto Nazionale di Fisica Nucleare of Italy, the United States Department of Energy, and the National Science Foundation of the United States.
In September 2014, as part of the testing of the CUORE dilution refrigerator, scientists in the CUORE collaboration cooled a copper vessel with a volume of one cubic meter to 6 mK (0.006 K, −273.144 °C) for 15 days, setting a record for the lowest temperature in the known natural universe over such a large contiguous volume. Provided by Wikipedia