Neutrinos are ghost particles. They pass through Earth as if it weren't there. To catch even one, physicists build enormous detectors. In the NOvA experiment, such a detector sits in Minnesota. Over years of operation, it has accumulated about a million muon antineutrino interactions. That's like catching a million grains of sand flying through a house-sized sieve.
Scientists measured three properties of each collision: the energy of the outgoing particle, its scattering angle, and the energy available for the reaction. This three-way split lets them separate different types of interactions. Previously, these were mixed together in a single signal, like voices in a choir. Now each voice can be heard individually.
Comparing the data with theoretical models revealed discrepancies that depend on energy and angle. This means the models need refinement. The new data will serve as a benchmark for future neutrino experiments.
Neutrinos interact so weakly with matter that a lead plate a light-year thick would stop only half of them.
In Stanisław Lem's novel "Solaris," neutrinos are mentioned as elusive particles that are difficult to detect.