How CERN’s Discovery of Exotic Particles May Affect Astrophysics

universetoday.com ^ | April 10, 2014 | Brian Koberlein on

[BenLurkin]

Very simply, the traditional model of a neutron star is that it is made of neutrons. Neutrons consist of three quarks (two down and one up), but it is generally thought that particle interactions within a neutron star are interactions between neutrons. With the existence of tetraquarks, it is possible for neutrons within the core to interact strongly enough to create tetraquarks. This could even lead to the production of pentaquarks and hexaquarks, or even that quarks could interact individually without being bound into color neutral particles. This would produce a hypothetical object known as a quark star.

[Telepathic Intruder]

Unconfined quarks, typically referred to quark-gluon plasma, or quark soup, has not officially been created in colliders yet, but they’re close. It only needs about 4 trillion degrees. It’s been theorized to exist in the cores of neutron stars for several years, though.

[Pox]

How matter interacts in such a dense environment will likely always be an exercise in theoretical physics.

I’m much more interested in how that environment continues to resist collapsing into a singularity.

[Telepathic Intruder]

You need a certain mass/density threshold for a black hole to form. Neutron stars are the very next thing below that. For something like the Earth, crushing it to about 0.7 inches in diameter would just do it. No such force exists in the universe, though. It requires something the mass of a few suns.

[Pox]

Although I understand the mass needed to supposedly create a singularity, I'm interested in the actual forces keeping a Neutron star from collapsing. What exactly is going on in there? Is it simply not enough mass/gravity to complete the collapse, or is there enough energy being generated (by what, who knows, perhaps just the energy of the quarks themselves) to counteract the gravitational forces?

Just pondering...

[dr_lew]

This could even lead to the production of pentaquarks and hexaquarks, or even that quarks could interact individually without being bound into color neutral particles.

That's Rockin' Good News !

[dr_lew]

Well, what is it that prevents the earth or the sun from collapsing into a black hole? Same question. Maybe an easier answer, but it’s not trivial, and no different in kind from any such answer, I would say.

[Telepathic Intruder]

In a neutron star, the only force preventing further collapse is the Pauli exclusion principle, which basically means that two fermions (normal matter including quarks) cannot share the same quantum state. That is, they cannot be in the same place while sharing the same momentum. So the closer they get together, the faster they must move, which creates pressure to balance gravity.

If neutron stars are made of neutrons, it’s called neutron degeneracy. With quark soup it would be called something else. But in the case where the mass/density becomes high enough for an event horizon to form (now referring to general relativity instead of quantum mechanics), not even that can prevent further collapse to the hypothetical singularity.

[itsahoot]

pentaquarks and hexaquarks

Those two rock bands have been performing down the street from me for a couple years.

[waredbird]

Hank Aaron is unimpressed.