State the charge of an up quark in units of \(e\).

State the charge of a down quark in units of \(e\).

What particle mediates the strong interaction between quarks?

Find the charge of \(uud\).

Find the charge of \(udd\).

What is colour charge?

Why are free isolated quarks not observed?

Find the charge of a \(u\bar s\) meson.

What is the baryon number of one quark and one antiquark?

Why must observable hadrons be colour neutral?

Find the charge and baryon number of \(sss\).

Find the charge of \(d\bar u\).

Explain why a proton and neutron have similar masses despite different charge.

Why are gluons different from photons in the way they interact with their own field?

A hadron has baryon number \(+1\), charge \(0\), and contains only up and down quarks. Identify a likely quark content.

Use quark content to explain the charge conservation in \(n\to p+e^-+\bar\nu_e\).

A meson has quark content \(s\bar u\). Find its charge and baryon number.

Why does adding energy to separate quarks produce jets of hadrons in high-energy collisions?

Explain why a \(qq\) two-quark state is not an ordinary observed meson or baryon.

How do fractional quark charges still produce integer hadron charges in common hadrons?