Sombra

The antineutron is the antiparticle of the neutron. It was discovered by Bruce Cork in the year 1956, a year after the antiproton was discovered. An antineutron has the same mass as a neutron, and no net electric charge. However, it is different from a neutron by being composed of antiquarks, rather than quarks. In particular, the antineutron consists of two anti-down quarks and one anti-up quark.

The magnetic moment of the antineutron is the opposite of that of the neutron. It is +1.91 µN for the antineutron but -1.91 µN for the neutron (relative to the direction of the spin). Here µN is the nuclear magneton.

Since the antineutron is electrically neutral, it cannot easily be observed directly. Instead, the products of its annihilation with ordinary matter are observed.

gunnut

Wow, very interesting. I didn't know neutrons are just clumps of quarks.

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ArmchairGeneral

Yep, same as protons. Only protons are composed of different kinds of quarks than neutrons. And electrons don't have any smaller components. Except for strings... maybe.

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dalem

Hmm. Are photons not just photons?

-dale

ArmchairGeneral

The way I understand it, yeah, photons have no component parts. None of the force carrier particles have sub-components or antiparticles, they simply are what they are.

hello

Neutrons and protons are not just clumps of quarks by themselves. They're a trio of quarks held together by even smaller gluons(The name gives it away.). There are also things called muons, tau leptons and bosons, which are also subatomic particles of various kinds.

HistoricalDavid

The W and Z Bosons are transmitters of the strong and weak nuclear force, specifically, like the photon for the electromagnetic. The graviton might also exist, but because of the pathetically weak nature of gravity in comparison to the other forces, it's unlikely ever to be detected.

The Chap

Sorry to be a pedant, but we cannot say "they" DO exist, only that the experimental evidence fits a (or the, for there are many variations) model. At best all are not merely approximate but indeed utterly contingent.

Upon what you may ask? Well there in lies the rub ...

Being proven wrong is the ongoing bug-bear of the scientist.

The methological charybdis is when the boys ignore the inconvenient ...

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highsea

Not different "kinds" (technically flavors), but a different combination of the same kind. Protons being 2 "up quarks" and 1 "down", neutrons being 2 "downs" and 1 "up".

Gunnut- the Standard Model provides 12 fundamental particles- 6 quarks and 6 leptons. All matter is some combination of these 12 particles. Each particle has an associated anti-particle, and all anti-matter is some combination of the 12 anti-particles.

Quarks are social and only exist in combinations with other quarks. Leptons exist as weak doublets, and do not combine into groups. There are 3 flavors of lepton- electron, muon, and tau. Each one has it's associated neutrino, and that makes up the 6 leptons in the Standard Model.

Quarks combine in 2 different ways- there are 3-quark combinations that make up baryons (protons and neutrons) and 2-quark combinations (quark and anti-quark) that make up the mesons. The combinations are always color-neutral. There is no such thing as a 4-quark combination, since it wouldn't be color-neutral. This family of particles is known as Hadrons.

For Bosons (the force carriers) like Photons and Gluons, there is no distinction between antimatter and normal matter, since they are charge-neutral. Also, the Pauli Exclusionary Principle doesn't apply to Bosons.

One must keep in mind that these are mathematical constructs, and not actually particles per se.

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