Neutrinos are getting in the way of dark matter detection

These troublesome particles are difficult to detect, but they're starting to show up in places where they're not wanted

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As a physicist, I, of course, love all the little particles. Each particle species has a role to play in the Universe and studying them helps us better understand the laws of nature that govern our existence. But as a dark matter researcher, I have to admit that neutrinos are unique in their ability to make life difficult.

Neutrinos are slippery little beasts. From their very conception they were, by all accounts, problematic.

They were first hypothesised as a desperate attempt to explain why some radioactive decays seemed to break the conservation of energy principle. When the decay occurred, the total measured energy of the decay products wasn't enough to account for the energy that went in. Which seemed impossible.

The physicists were thus faced with two bad choices: either abandon conservation of energy, or assume that there's an invisible particle produced in the decay, unseen by the detectors. Reluctantly, they chose the latter, eventually dubbing the new particle “little neutral one” because whatever it was, it definitely had no electric charge and seemed to be massless.