A recent theoretical study conducted by the Tata Institute of Fundamental Research (TIFR) suggests that fast neutrino oscillations may be the catalyst for supernova explosions. This raises our understanding to a new level about these subatomic particles and their role in the universe.
Breaking Down Neutrinos and Their Properties
Neutrinos are subatomic particles that share similarities with an electron but are distinct due to their lack of electrical charge and extremely small mass – which could potentially be zero. Known as one of the most abundant particles in the universe, their limited interaction with matter makes them difficult to detect.
Electrons and Neutrinos receive identical treatment from nuclear forces; they neither participate in the strong nuclear force, nor the weak nuclear force. The commonality between these particles led to the term “Leptons”.
Natural Sources of Neutrinos: From Earth to Sky
Neutrinos are naturally emitted from a variety of sources. This includes the radioactive decay of primordial elements within the Earth, radioactivity in the Sun, and cosmic interactions happening in the atmosphere amongst other occurrences.
Different Flavours of Neutrinos
There are three ‘flavours’ of neutrinos – electron neutrino, muon neutrino, and tau neutrino. They are named after the corresponding leptons they are associated with, namely electron, muon, and tau.
Unpacking Fast Neutrino Oscillations
Fast neutrino oscillations occur when the different flavours of neutrinos are emitted slightly differently in various directions (anisotropy) in the presence of many other neutrinos, causing a higher frequency of oscillations from one flavour to another. The frequency is proportional to the density of neutrinos, not their masses.
A Brief Glimpse at Supernovas
A star that implodes due to its own gravity after depleting its fusion fuel is termed a supernova. Usually, stars more massive than eight times the mass of our Sun undergo this explosive phase.
A Leap in Understanding Fast Neutrino Oscillations
| Star Mass Required for Supernova | Eight Times the Sun’s Mass |
|---|---|
| Density Required for Fast Neutrino Oscillations | High Density |
| Condition Required for Fast Neutrino Oscillations | Anisotropy |
The Outcome of TIFR’s Study and Its Implications
The breakthrough from this research lies in treating neutrino collisions and oscillations together in one calculation. Prior assumptions suggested that under high-density and anisotropy conditions, neutrinos would travel in straight lines without colliding. The study has shown, however, that collisions can lead to high anisotropy conditions and, consequently, induce fast oscillations under appropriate circumstances. The property of anisotropy refers to observable differences in physical properties along different molecular axes and is notable in crystals, liquid crystals and, less commonly, liquids.