What are neutrinos?

Physicists working with the Kamioka Liquid Scintillator Antineutrino Detector (KamLAND) in Japan recently reported that after analyzing two years’ worth of data, they were unable to discover any indications that neutrinos could be their own antiparticles. What does it mean?

What exactly is an antiparticle? Every form of particle has an antiparticle with the same mass but opposite physical charges, according to quantum theory. If the two meet, they will destroy each other, producing light.

For example, the positron is the antiparticle of the electron. Neutrinos have particles called anti-neutrinos. But you can tell the difference between an electron and a positron because they have different charges. Neutrinos and anti-neutrinos aren’t really different from each other because neither has an electric charge or any other real difference. Neutrinos don’t have a clear answer to the question of whether or not they are their own antiparticles. If they were, physicists could explain why there is more matter than antimatter in the universe. But an experiment in Japan recently failed to find “strong evidence” that this is the case, ruling out certain—but not all—theories.

Why we exist?

When the Universe was made, the Big Bang theory says, there would have been the same amount of matter and antimatter. As the Universe got cooler, matter and antimatter would destroy each other, leaving only light. But since we are here, that didn’t happen. So, something stopped matter and antimatter from cancelling each other out. We don’t know what caused that imbalance, and if we did, we’d know why we exist. One of the largest open questions now is whether or not neutrinos violate some theory. A matter-dominated Universe suggests this. The only place we have not yet looked to answer this question is neutrinos.

About Neutrinos:

• Neutrinos are mysterious particles generated in abundance by nuclear reactions in the Sun, stars, and elsewhere. Neutrinos are made by different kinds of radioactive decay, like when cosmic rays hit atoms or during a supernova.
• After photons (light particles), neutrinos are the second most prevalent particles in the universe.
• Despite their abundance, our knowledge of neutrinos is limited as their minimal interactions with matter make them very difficult to detect.
• They also “oscillate,” which means that various neutrino types transform into one another.
• Neutrino oscillations and how they relate to mass are very important for studying how the universe began. 
• Neutrinos are excellent carriers of information from parts of the universe that we don’t have access to, like bursting stars and black holes.