It appears we might have the first genuine detection candidate for a DM particle in one of our liquid xenon detectors:

Berkeley Lab News Center

LZ Sees Surprising Result in Search for Dark Matter

Of course, a single detection event - if it is confirmed to be real - does not yet constitute a discovery, but it is interesting.

3 hours ago, Markus Hanke said:

It appears we might have the first genuine detection candidate for a DM particle in one of our liquid xenon detectors:

Berkeley Lab News Center

LZ Sees Surprising Result in Search for Dark Matter

Of course, a single detection event - if it is confirmed to be real - does not yet constitute a discovery, but it is interesting.

I know next to nothing about the physics proposed for WIMPs (if they exist). But if they are not subject to the EM interaction, in what sense can a WIMP "collide" with an atom of Xe? Something to do with the Strong Force? Or something else? And why would this create a cascade of electrons?

4 hours ago, exchemist said:

I know next to nothing about the physics proposed for WIMPs (if they exist). But if they are not subject to the EM interaction, in what sense can a WIMP "collide" with an atom of Xe? Something to do with the Strong Force? Or something else? And why would this create a cascade of electrons?

The weak interaction, perhaps.

If there is momentum transfer to the nucleus, you can leave electrons behind.

The process of detection is based on the direct hit and recoil of a WIMP with the Xenon atomic nucleus.
These events are exceedingly rare, and so, require very large amounts of pure liquified Xenon.
IOW, what Swansont said.

1 hour ago, MigL said:

The process of detection is based on the direct hit and recoil of a WIMP with the Xenon atomic nucleus.
These events are exceedingly rare, and so, require very large amounts of pure liquified Xenon.
IOW, what Swansont said.

Would the Weak interaction produce a force of mutual repulsion then?

I think I read that the new Nancy Grace telescope is hoped to be effective at studying Dark Matter.

So,fingers crossed.I think it will take a few months before it reaches its "mooring position"

3 hours ago, exchemist said:

Would the Weak interaction produce a force of mutual repulsion then?

Not as far as I know; it is more of a collision, producing a recoil of the xenon nucleus.

"WIMPs would be expected to interact exclusively with the liquid xenon nuclei, resulting in nuclear recoils that would appear very similar to neutron collisions. In order to single out WIMP interactions, neutron events must be minimized, through shielding and ultra-quiet building materials."

From Large Underground Xenon experiment - Wikipedia

Some excitement here - we live about 25 miles from the detector, located at the SURF Lab, in the old Homestake Gold Mine in Lead, SD. DK if they still have Neutrino Days*, but that was an annual weekend up there when you could visit the lab. Possibly the only nerd tourist attraction in the Black Hills. OK, there's a geology museum in Rapid City, too. Sort of.

* WIMP Days was also considered but for some odd reason didn't make the final cut.

1 hour ago, MigL said:

Not as far as I know; it is more of a collision, producing a recoil of the xenon nucleus.

"WIMPs would be expected to interact exclusively with the liquid xenon nuclei, resulting in nuclear recoils that would appear very similar to neutron collisions. In order to single out WIMP interactions, neutron events must be minimized, through shielding and ultra-quiet building materials."

From Large Underground Xenon experiment - Wikipedia

A collision must imply a force of repulsion, surely? These are QM entities, after all, not billiard balls.

1 minute ago, exchemist said:

A collision must imply a force of repulsion, surely? These are QM entities, after all, not billiard balls.

Or attraction. Celestial bits and bodies can impart momentum to each other without actually touching.

In QM it’s an exchange of a virtual particle, and that can be attractive or repulsive

1 hour ago, exchemist said:

A collision must imply a force of repulsion, surely? These are QM entities, after all, not billiard balls.

Sorry @exchemist
Didn't really clue in as to what you were asking.
As far as I know there is no repulsion or attraction, as with EM forces, and I would assume the interaction involved is the weak, as WIMPs must interact via the weak interaction.
There is obviously an 'exchange force' because momentum is transferred ( similarly to a collision of billiard balls ).
It is this momentum transfer, and resultant recoil of the nucleus, which leads to the electron effects and their electroluminescence ( which is detected )