# Tag Info

### Why are all quarks and leptons of this universe the same?

Fairy Physics It is entirely possible to construct a theory of the universe which states: "All effects are caused by fairies. Each effect has its own fairy, and every fairy is unique. When two ...
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• 24.8k

### Is there a quark conservation law?

Yes, there are the quantum numbers Charm, Strangeness, Topness and Bottomness, which are conserved by strong and electromagnetic interactions, but not by weak interactions. Upness and Downness are ...
• 3,362
Accepted

### $SU(3)_F$ flavour symmetry and $SU(2)$ isospin symmetry

Both SU(3) flavor and SU(2) isospin are approximate symmetries of the Standard Model at low energies. Consider physics below the proton mass, where we can talk about the pions and kaons that are the ...
• 976
Accepted

### Can muons decay into quarks?

No, muons can't decay into quarks because quarks are confined; the final product cannot be quarks, but rather composite particles made of quarks, such as mesons and baryons. The lightest mesons are ...
• 94.9k
Accepted

### Why is the mass of the proton such a precise value?

You say: a zillion gluons and quarks and anti-quarks self annihilating and popping into existence and while this is a very common way to describe the interior of a hadron like a proton it is ...
• 329k
Accepted

### What are Quarks made of and will they ever decay to this?

Quarks as we know them are fundamental particles, which means that they do not have smaller constituents. This however does not imply that they cannot decay. A particle in quantum field theory does ...
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### How (or when) do gluons change the color of a quark?

The model you are thinking about is really rudimentary and cannot explain the dynamics of Quantum ChromoDynamics, QCD . In this link there is a better exposition of what a proton is, within QCD. ...
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### How can $\Lambda^0$ and $\Sigma^0$ both have $uds$ quark content?
The isospin is different. $I=0$ for the $\Lambda^0$ and $I=1$ for the $\Sigma^{0}$. This makes the $\Lambda^0$ an isospin singlet state but the $\Sigma^0$ is part of an isospin triplet. There are ...