Great article. I hope your students liked it. As usual, some comments from me, but they always come later relatively to the posting date... ;)
This is a good thing, as it allows research to continue seeking for answers and it promises some physics beyond the standard model, that will allows us to grasp even deeper intricacies of reality.
The only question being: will we discover it soon, later or much later :)
Combining 5 quarks together might form pentaquarks. However, scientist are not sure yet that these are effectively 5 quarks tied by the strong force, or if this object results of a baryon and a meson bound together like in an atomic nuclei. [Source]
Actually, pentaquarks have been discovered too, by the LHCb experiment at CERN. See here.
Many other baryons exists, the Sigma, the Xi, the Omega etc… all coming in various flavors depending on their quark composition. Check this list for a more extensive view.
For the list of all known particles (inclusding baryons and mesons), I would refer to the Particle Data Group.
Ah yes, that is a question I discuss with my students when we approach particle physics, It's a great way to show them that science is always a work in progress...
Thank your for the link. I was not writing that the pentaquark has not been discovered yet, but that we still are not sure about its configuration: it is a real pentaquark or a combination of a baryon and a meson? In the link, the same question appears:
"the LHCb researchers conjecture that the pentaquark could be a tightly bound (spherical) system of all five quarks , or a “molecular” system consisting of a weakly bound baryon and a meson " (source:https://physics.aps.org/articles/v8/77)
Wow, I checked it out, this is pretty extensive! Thanks you!
Sorry, I read too fast. Shame on me ;)