Neutrinos, the puzzling elementary particles with neutral electric charge and tiny mass, are among the most abundant particles in the Universe, a billion times more than the matter particles that make up stars and galaxies. However, they interact with matter very rarely, and as such they are very difficult to detect and study. We know today that there are 3 different types of neutrinos and they can transform into one another via the quantum process of "neutrino oscillations", only possible if neutrinos have a non-zero mass. This was observed by the Sudbury Neutrino Observatory (SNO) and the Super-Kamiokande experiments, solving the problems of the "missing solar neutrinos" and the "missing atmospheric neutrinos", and leading to the 2015 Nobel Prize in Physics. Since then, other experiments have confirmed the effect with neutrinos created by particle accelerators and nuclear reactors. Besides this unique behavior, it is possible that neutrinos are Majorana particles, i.e. that a neutrino is its own anti-particle, with potential implications on the explanation of the matter/anti-matter asymmetry in the universe.

The LIP Neutrino Physics group is involved in the currently operating SNO+ experiment, and in DUNE, one of the leading neutrino physics experiment for the next decade. The group activities thus combine data analysis with R&D on future detectors.

The LIP group joined the SNO experiment in 2005 and is a founding member of the SNO+ collaboration. The main goal of SNO+ is the search for the neutrinoless double-beta decay of Tellurium-130, but several other physics topics are part of its program: antineutrinos from nuclear reactors and the Earth's natural radioactivity, solar and supernova neutrinos, and searches for new physics. SNO+ reuses the SNO detector located 2 km underground, replacing the 1 kton of heavy water with liquid scintillator, and observing the tiny flashes of scintillation light with an array of 9300 light sensors. The group has participated in the construction of calibration systems, and is currently very active in the analysis of the water phase data, with leadership or strong contributions to physics analyses (backgrounds and antineutrino studies), calibrations, and data quality. The scintillator fill is currently underway, and so the group's efforts will gradually shift from water phase to scintillator phase data analysis.

In 2018, the group joined the DUNE collaboration, that aims to measure one of the missing parameters of neutrino oscillations, the "CP violation phase". This will tells us how different is the behavior of neutrinos and anti-neutrinos and also has strong implications on the explanation of the matter/anti-matter asymmetry in the universe. For that, neutrino and anti-neutrino beams will be produced at Fermilab and detected both near the origin and 1300 km away at an underground laboratory in South Dakota, in large high precision detectors using liquid argon. DUNE also has additional physics goals, such as the measurement of supernova neutrino bursts and the search for proton decay. The beam is expected in 2026, and the first detector installation in 2025 but R&D with large detector prototypes (ProtoDune) is ongoing at CERN. Our activities will initially focus on design of the far detector calibration systems and operation/data analysis of the ProtoDUNE detectors at CERN.

 

Photos

Contacts

Group Leader:  

José Maneira

maneira@lip.pt