Researchers Find Possible Key To The Theory Of Everything

Ninety years after its prediction and 25 years since the Nobel Prize was awarded for its discovery, the neutrino particle is still surprising us. It may, in fact, be the key to understanding everything. Physicists are homing in on the mass of the neutrino, nature’s most elusive subatomic particle. The latest super-accurate measurement, made by an experiment in Germany, shows that the neutrino is around half a million times less massive than the electron, the lightest particle of normal atomic matter.

According to the Standard Model, the high point of 300 years of physics which describes the fundamental building blocks of matter and three non-gravitational forces that glue them together, the neutrino should be massless.

So why should we care about a mass measurement (no matter how tiny) of a neutrino? Well, it may provide vital clues to the fabled ‘theory of everything’ – a deeper, more fundamental theory of physics of which the Standard Model is believed to be but an approximation. The latest neutrino measurement was made in Karlsruhe, Germany, where physicists exploited the ‘beta decay’ of tritium. Tritium is a heavy type – or ‘isotope’ – of hydrogen. In beta decay, the unstable core – the ‘nucleus’ – of an atom sheds surplus energy by spitting out an electron and an antineutrino (the neutrino and its ‘antimatter’ twin have the same mass).

Neutrinos are fantastically antisocial, interacting so rarely with normal matter that they could pass unhindered through several light-years of lead. Consequently, the physicists at the Karlsruhe Tritium Experiment, or KATRIN, must infer the neutrino mass from measurements made on their electrons. 

Looking inside the large electrostatic spectrometer, the heart of the Karlsruhe Tritium Neutrino Experiment, KATRIN ? Michael Zacher

They can do this because the amount of energy emitted by the tritium nuclei is always the same. The energy is divided between the electron and the neutrino – if an electron has lots of energy, then it must mean that its associated neutrino only has a little bit. So if the physicists only allow the most energetic electrons to reach their detector, it ensures that their associated neutrinos will have very little energy – this allows them to make a more accurate reading of the neutrinos’ mass.

Knobull suggests the review of added details at: 

Read in BBC Science Focus Magazine: https://apple.news/AKolj0MEVSouNyODd_ZvCeQ