Question Video: Recalling the Symbols Used to Represent Neutrinos Physics

Video Transcript

Which of the following symbols does not represent a real neutrino?

So here we have a list of four answer options, and each one consists of a lowercase Greek letter 𝜈. This is a character that looks kind of like a curly letter V, and each one is followed by a different letter written in subscript. This first one is the Greek letter 𝜇. This one of course we know as the letter 𝑒. This character looks like an E, but it’s actually a lowercase Greek letter 𝜖. And finally, this is the Greek letter 𝜏. What we need to do is determine which of these does not represent a real neutrino.

We can recall that all neutrinos are represented by the Greek letter 𝜈. We can also recall that there are three varieties of neutrino: the electron neutrino, the mu neutrino, and the tau neutrino. Each of these also has its own antiparticle. These are the electron antineutrino, the mu antineutrino, and the tau antineutrino. As we can see, these particles are named after the negatively charged leptons: the electron, muon, and tauon. And these negatively charged leptons are represented by the symbols 𝑒 minus, 𝜇 minus, and 𝜏 minus. Because the neutrinos are named after these three leptons, they also make use of the symbols 𝑒, 𝜇, and 𝜏. So we represent an electron neutrino with a letter 𝜈 to signify that it’s a neutrino, followed by a subscript 𝑒 to signify that it is an electron neutrino.

Similarly, the muon neutrino is represented by a 𝜈 followed by a subscript 𝜇. And the tau neutrino is represented by a 𝜈 followed by a subscript 𝜏. The antineutrinos follow the same pattern, but with a bar over the top to signify that they are antineutrinos. So looking again at our answer options, we can see that option (A) corresponds to a mu neutrino, option (B) corresponds to an electron neutrino, and option (D) corresponds to a tau neutrino. So we can see that it’s option (C), 𝜈 sub 𝜖, which does not represent a real neutrino.