Hey @lemouth!
Even if it is very elusive, dark matter can be directly observed in a detector placed on Earth.
I must say I already learned something new in the first two lines. What kind of material is being used in such detectors and how do we explain the fact that dark matter particles only interact with the detector material once in a while?
The heart of the proposal consists in investigating how these stones could contain a persistent chemical or structural change caused by a dark matter particle hitting one of the atomic nuclei of the stones.
So they basically estimate the dark matter interaction relatively to the dark matter mass? Is that how dark matter models are created?
Thanks for another interesting read!
Thanks for those very nice questions!
Dark matter must be very weakly interacting with the Standard Model. Therefore, it must be very weakly interacting with normal matter (made of standard model particles). However, "very weakly" does not mean "not interacting". The interactions are super rare, but they happen. By constructing a super large detector, we hence multiply the chance to have such interactions.
The best current choices are detectors mande of xenon gas. You can for instance see here. The xenon-1T (1T stands for 1 ton) experiment has recently released its new results.
It works both ways. By the size of the limits for a given mass, we can have some idea about what makes a model viable. In the other way round, when starting from a model, we can predict the production rate. `the main dependence of the production rate comes from the dark matter mass, which explain the chosen representation for the results.
Is it clearer? :)
Thanks for another great article. We haven't observed any interactions between dark matter and normal matter, so I don't understand how we can be sure that interactions do in fact happen?
We construct models to explain the observations, and these models predict that to some extent, dark matter interact with normal matter. There is no way out if one wants to reproduce data. Those interactions are very weak, but they must be there.
I understand, thank you for the explanation
You are very welcome! :)
It is a lot clearer now, thanks for taking the time to provide detailed answers! Have a great day!
Thank you! I always take the time to answer, even if the answer may be delayed a little bit. Have a good "whatever" (it is night at the moment) as well :)