Far out cosmology: dark matter research goes nowhere (Introduction)

by David Turell , Monday, February 25, 2019, 17:19 (2096 days ago) @ David Turell

WIMPS, very weak particles which were supposed to be related have not been found:

https://www.forbes.com/sites/startswithabang/2019/02/22/the-wimp-miracle-is-dead-as-dar...

"As of 2019, we've met with tremendous success on those fronts that have confirmed the Standard Model in ways that both theorists and experimentalists could have only dreamed of half a century ago. Detectors at colliders and isolated, underground facilities have led the way forward.

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"We understand how the Standard Model particles behave. We have solid predictions for how they should interact through all of the fundamental forces, and experimental confirmation of those theories. We also have extraordinary constraints on how they're permitted to interact in a beyond-the-Standard-Model fashion. Because of our constraints from accelerators, cosmic rays, decay experiments, nuclear reactors and more, we've been able to rule out many possible ideas that have been theorized.

"When it comes to what might make up the dark matter, however, all we have are the astrophysical observations and our theoretical work, in tandem, to guide us. The possible theories that we've come up with include a huge number of dark matter candidates, but none that have garnered any experimental support.

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"The most sought-after dark matter candidate is the WIMP: the Weakly Interacting Massive Particle. In the early days — i.e., back in the 1970s — it was realized that some particle physics theories that predicted new particles beyond the Standard Model could eventually produce new types of stable, neutral particles if there were some new type of parity (a type of symmetry) that prevented them from decaying.

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"If there is WIMP dark matter, it must be weaker than the weak interaction permits to comprise 100% of the dark matter. Additionally, the LHC should not detectably produce it.

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"The WIMP miracle may be dead and gone, as particles interacting through the weak force at the electroweak scale have been disfavored by both colliders and direct detection. The idea of WIMP dark matter, however, lives on. We just have to remember, when you hear WIMP, we include dark matter that's weaker and wimpier than even the weak interactions will allow. There is undoubtedly something new out there in the Universe, waiting to be discovered.

"The WIMP miracle is over. But we still might get the best miracle of all: if these experiments turn up something beyond a null result. The only way to know is to look."

Comment: Something must cause dark matter. Keep looking.