Thanks, those are really informative.

Anyone know what the typical lag is between measurement and discovery for these kind of experiments? From reading between the lines, it seems to me that this discovery is based on re-analysis of the 2016 measurement data, but they don't mention the dates when the data was collected. I had expected the turnaround time to be in the order of months rather than years, e.g. 6-9 months to analyze experimental data, 6 months to prepare for publication, so let's say 1.5 years between experiment and claimed discovery. But this may be hopelessly naive, I don't have any comparable experience to rely on.

Also, what's the typical lifetime of these tetraquarks? None of these configurations are stable, so is it even accurate to call them "particles"?

Yeah, don't know much more about them than that. The post is a pretty short breakdown of the Standard Model and LHC's contribution to it.

The Earth is not large enough to build a particle collider big enough to test if String Theory describes the most elemental particles or if there is something smaller. We might be only a handful of generations of particle accelerators until spaced based colliders. All of this is to say, you’re going to need to be okay with you personally never knowing this answer. It’s all theoretical.

I cannot comprehend what would be inside a particle that would be a smallest possible one. Division to infinity feels calming.

Seems to me that the way the universe prevents naked quarks from existing blocks particles from getting any smaller.