Question

Do neutrinos have mass?

Answer 1

Nuclear reactions such as those that create heavy elements also create vast numbers of ghostly subatomic bits known as neutrinos. These belong to a group of particles called leptons, such as the familiar electron and the muon and tau particles. Because neutrinos barely interact with ordinary matter, they can allow a direct look into the heart of a star. This works only if we are able to capture and study them, something physicists are just now learning to do. 

Not long ago, physicists thought neutrinos were massless, but recent advances indicate that these particles may have a small mass. Any such evidence would also help validate theories that seek to find a common description of three of the four natural forces—electromagnetism, strong force, and weak force. Even a tiny bit of heft would add up because a staggering number of neutrinos are left over from the Big Bang. 

Answer 2

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HERE'S YOUR ANSWER

:-Neutrinos are considered massless, because no mass was observed. The way we know, now, that neutrinos have masses, is through the mixing between the different neutrino types.

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