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20 May 2024

The NOvA Experiment

Leading Efforts to Discover the Neutrino Mass Hierarchy

Neutrino physics has made great strides in the past twenty years. It seems the new and startling discoveries never stop where this tiny elusive particle is concerned. Today, we know that there are three types of active neutrino, the electron, muon, and tau neutrino, and that they oscillate between three mass states. This is an important definite signal of physics beyond the Standard Model of particle physics and measuring the neutrino's properties could help explain the matter/anti-matter asymmetry of the Universe, provide hints about why we have three generations of particles and possibly open the door to even more strange findings. One very important fact that we currently do not know is which neutrino mass state is heaviest? Is it the third (normal mass hierarchy)? Or is it the second (inverted mass hierarchy)? This is one of the most important questions NOvA is attempting to answer. Neutrinos interact only weakly and so rarely that experiments with giant detectors are needed in order to make the all-important new measurements and discoveries. NOvA is such an experiment and uses a muon neutrino beam, the NuMI beam, as its source of neutrinos, observes the neutrinos before they have oscillated (changed into electron and tau neutrinos) in a Near detector at Fermilab, and then observes the same beam again after the neutrinos have oscillated in the NOvA Far detector 810km away in Ash River in Minnesota. NOvA is currently taking data and has a real chance of making the next big discovery in neutrino physics.


The UCL HEP physics group joined the NOvA experiment in 2015 and is only the second institution in the UK to collaborate on NOvA, after Sussex University. Our group is already relatively large and is now very active on the experiment. We are involved in a variety of topics including detector calibration, understanding the neutrino beam flux, and understanding analysis backgrounds. We also actively participate in the neutrino oscillations analyses themselves.

If you would like more information about NOvA at UCL, please contact Dr. Anna Holin