# Tag Info

Accepted

### Why is the charmed eta meson its own antiparticle, but the neutral kaon is not?

Mesons are not elementary, they are composed of quarks. So take a look at their quark content. The charmed eta meson consists of a charm and an anti-charm quark, denoted $c\overline{c}$. An anti ...
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### Are there any Baryons that have quark-antiquark combinations?

No, a three-quark baryon can not be be made out of two quarks and one anti-quark (and vice versa) as this would necessarily give the particle color. Each quark carries one of three colors (red, blue, ...
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### Are there any Baryons that have quark-antiquark combinations?

Pentaquarks contain three quarks and a quark-antiquark pair, and they are baryons, since baryons are defined as having an odd number of valence quarks.
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### Why does charmonium (and phi mesons) not decay via quark and antiquark annihilation?

That is more or less what we do, except... Annihilation through a photon is electromagnetic rather than strong, so this is a suppression. Annihilation through a single gluon can't happen because the ...
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### Meson as hadron and boson

Since a meson is composed of two spin 1/2 particles, its total spin must be an integer, which makes it a boson.
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### Does the Pauli exclusion principle apply to mesons?

So I guess the answer here is both yes and no. The best example of this is probably the existence of bose einstein condensates in laboratories. These are (almost) always made up of atoms that exhibit ...
Accepted

### What's the difference between a meson and a glueball?

This is a good question, and the basic answer is "there is no rigorous difference" (which is the main problem with experimental efforts to identify glueballs). 1) Electrically charged states, or ...
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### What is a sigma meson?

For example: The existence and properties of the sigma meson have been controversial for almost six decades, despite playing a central role in the spontaneous chiral symmetry of QCD or in the ...
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### Does an Anti $\eta^0$ meson exist?

The antiparticle of eta meson is the eta meson itself. $$\eta = \dfrac{1}{\sqrt{6}}(u\bar{u} + d\bar{d} -2s\bar{s})$$ As you can see, since the eta is composed of the terms $q\bar{q}$, therefore ...
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