Physicists confirm 67-year-old prediction of massless neutral composite particle

Praise the church of experts and their sanctioned interpretations of divine esoteric measurements

Can someone give me a TL;DR on how they detected these things, if they don't interact with light and have no electric charge? Do they only exist temporarily or something?

I'm sure it'll grow on me, but "Demon" sounds like a dumb name. Then again, so is "neutrino" if you know why it's called that.