Bottomonium Particles

19 Jul 2019

One for the birds. At https://phys.org/news/2019-07-bottomonium-particles-dont.html ... a few millionths of a second after Big Bang the universe was so dense and hot that quarks and gluons (that make up protons, neutrons and other hadrons) existed freely in what is known as the quark-gluon plasma. All hypothetical of course. Apparently, they aim to recreate this situation at the Large Hadron Collider (and some early results are said to be promising) via high energy collisions of heavy ions of lead. The add on here is that they cannot actually observe what is going on - or the state of the matter inside the collider. The presence and property of the plasma can only be deduced via the signature it leaves on the particles that are produced in the collision. A paper was read out at the European Physical Society conference on high energy physics and reports on one signature currently identified (via elliptic flow), an upsilon particle produced in lead-lead. The signature is a bottomonium particle consisting of a bottom quark and its anti guark. Bottominium, and charm-quark counterparts, charmonium particles, are said to be excellent particles of the quark-gluon plasma. They are created in the initial stages of heavy-ion collision.

See also www.arxiv.org/abs/1907.03169

Meanwhile, back in daylight, at https://phys.org/news/2019-07-toughen-glass-nanoparticles.html ... a new use for nano-particles - toughening glass (making it stronger and less likely to crack).