Oleg Zabluda's blog
Thursday, August 09, 2018
 
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In one set of experiments, we have determined that the half-life of a lonely neutron is 879.6s. But, in another set of experiments, we’ve found that the neutron has a half-life of 888s (these numbers might be slightly out of date now). The chance of these two being different by accident is now about one in 100,000.

One possible explanation for the difference is that a subset of neutrons decays to a relatively light particle of dark matter. Now, a pair of papers has punctured that proposal.
[...]
The method that finds the shorter half-life counts the number of neutrons in a bottle after an elapsed time. The second experiment counts the number of protons emitted by a beam of neutrons. The beam method would not count neutrons that did not decay to a proton. [...] One possibility is that sometimes neutrons decay into a baryonic dark matter particle. [...] electrically neutral and weakly interacting, we wouldn’t detect it by accident in either experiment.
[...]
To fit this idea into the world around us, we know that the new dark matter particle has to be heavy enough to cope with the observed stability of isotopes [...] and the stability of the proton. [...] Under reasonable circumstances, we might expect neutrons decaying to dark matter to affect the properties of neutron stars. [...] Adding dark matter with mass up to 1.2GeV renders neutron star models incompatible with observations
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https://arstechnica.com/science/2018/08/neutron-stars-are-probably-not-hiding-dark-matter-under-their-skirts/
https://arstechnica.com/science/2018/08/neutron-stars-are-probably-not-hiding-dark-matter-under-their-skirts/

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