Neutrinos, once considered ordinary particles, have now become the subject of extensive research requiring multi-billion dollar investments in scientific laboratories. These small particles are shrouded in secrets that have the potential to revolutionize our understanding of fundamental physics.
The story of neutrinos began with beta-decay, a process where heavy atomic nuclei spontaneously transform, emitting electrons or positrons. However, the energies of the emitted electrons did not align with the laws of conservation of energy. Physicists proposed the existence of a hidden particle that could account for this discrepancy, giving rise to the neutrino, which translates to “small neutral” in Italian.
After 25 years, the first neutrino was successfully detected. Initially thought to be just another particle, scientists later discovered three distinct types of neutrinos. These neutrinos belong to three different generations, each with its own counterparts of greater mass – electron with Muon and Tau-neutrino. These interactions are named electronic, muon, and tau-neutrinos.
Initially, neutrinos were considered massless, but further research revealed otherwise. An early challenge arose when studying neutrinos emitted by the sun, as detectors recorded only half of the expected number. This discrepancy suggested that neutrinos could change their “flavors” en route to Earth, explaining the deviation from theoretical predictions.
Experiments confirmed that neutrinos exist in three mixed masses (M1, M2, and M3), giving rise to the observed flavors. While the combined mass of all three neutrinos is known to be less than 0.1 EV/s², the exact masses of individual neutrinos remain elusive.
Traditionally, particles acquire mass through The Higgs mechanism. However, neutrinos possess only left chirality, raising questions about their interaction with the Higgs Boson. The possibility of a fourth neutrino responsible for this interaction or alternate mechanisms for neutrino mass remain enigmatic to current physics.
The study of neutrinos involves significant costs, with projects like the Ice