NEUTRINOS: The Ghost Particles

Neutrinos are the most common matter particle in the universe. Trillions of them move through our bodies every second without ever interacting with us. It is said that the sun itself produces enough neutrinos to send 60 billion of them through your thumbnail every second.

The current best estimate says that the sum of the masses of three neutrinos is about below one electronvolt. For comparison, one electron has a mass of 511,000 electronvolts. Put another way, a neutrino is 10 billion, billion, billion times smaller than a grain of sand.

Why are they so important?

Neutrinos can easily fly through matter unaffected by magnetic fields. This means that they can travel across the universe in a straight line for billions of years, carrying information about where they came from. The highest energy neutrinos are born in the part of the universe that we know very little about. Something out there-maybe a super massive blackhole or a cosmic dynamo -accelerates cosmic rays a million times more than anything human built. These cosmic rays interact violently with matter and radiation around them, to produce neutrinos, which can tell us about the location and interior of the most powerful cosmic engines.

Neutrinos and Anti-Neutrinos?

Every particle has an antiparticle. Antiparticles have the same mass and rest energy but are oppositely charged. An antineutrino is thus simply an “opposite version” of a neutrino. But if one of the main ways matter and antimatter are opposites is charge, then what does it mean that neutrinos are neutral? Does that mean neutrinos and antineutrinos are the same thing? These are questions scientists are unsure of, however it is said that neutrinos have an anti-clockwise spin whereas antineutrinos spin clockwise.

How is that important?

If we reverse the spin of an anti-neutrino we would simply get a neutrino and vise versa. We all know that the universe started from nothing. This should mean that there used to exist equal amounts of matter and anti-matter in order to add up to nothing. Fortunately for us, something must have happened that somehow flipped a small amount of anti-matter to matter to stop the nothingness. So maybe neutrinos hold the key to understanding how it all happened! Understanding their properties and interactions could lead to breakthroughs in our understanding of the early universe and the fundamental forces at play during its formation.

Detection:

Neutrinos have a huge range of energies and also come in three different types, called flavors. Scientists have learned how to build detectors suited for each type of neutrino and their huge range of energies.

Scientists can tell these particles apart because each type leaves a different pattern in the detector. For example, muons leave straight tracks, electrons look like showers, and tau particles decay quickly to produce multiple straight tracks. Using the different patterns, scientists can decode the neutrino flavors and the hidden message carried by each ghostlike particle.