http://arstechnica.com/science/2015/10/missing-glueballs-are-sticky-problem-for-particle-physics/
The discovery of the Higgs boson was rightfully heralded as a triumph of particle physics, one that brought completion to the Standard Model, the collection of theories that describes particles and their interactions. Lost in the excitement, however, was the fact that we're still missing a piece from the Standard Model—another type of particle that doesn't resemble any other we've yet seen.
The particle is a glueball, but its goofy name doesn't express how interesting it is. Glueballs are unique in that they don't contain any matter at all: they have no quarks or electrons or neutrinos. Instead, they are made entirely of gluons, which are the particles that bind quarks together inside protons, neutrons, and related objects.
Particle physicists are sure they exist, but everything else about them is complicated, to say the least. Like so many other exotic particles (including the Higgs), glueballs are very unstable, decaying quickly into other, less massive particles. We don't have any ideas about their masses, however, which is obviously kind of important to know if you want to find them. We also don't know exactly how they decay, making it hard to know exactly how we'll identify them in experiments.
If I may be so bold, what do fellow SNs think of modern particle physics, and do any of you have any crazy alternative non-particle-centric physical theories (for example, a model of reality that works using 7-dimensional strings as opposed to 1-dimensional strings from string theory?)
(Score: 2, Interesting) by pTamok on Monday October 26 2015, @10:33PM
This review paper looks at possible glueball candidates in existing particle accelerator data:
Wolfgang Ochs (2013). "The status of glueballs". Journal of Physics G 40 (4): 043001. arXiv:1301.5183. doi:10.1088/0954-3899/40/4/043001. http://arxiv.org/abs/1301.5183 [arxiv.org]
It's not that there are no candidates, but so far none of the candidates have reached the necessary level of significance.
There is also very recent news about a particular candidate: the f0(1710) meson
http://www.livescience.com/52558-glueballs-potentially-found-lhc.html [livescience.com] which references http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.115.131601 [aps.org]
Another report of the same item: http://www.gizmag.com/meson-f01710-glueball-particle/39866/ [gizmag.com]
...and another http://www.techtimes.com/articles/94845/20151013/glueball-particle-nuclear-force.htm [techtimes.com]