Name the two main families of matter particles in the Standard Model.

What is a hadron?

State the quark content of a baryon and of a meson.

Why is an electron classified as a lepton rather than a hadron?

What is an antiparticle?

Find the charge of a proton from its quark content \(uud\).

Find the charge of a neutron from its quark content \(udd\).

Why does a meson have baryon number zero?

Classify a pion as a baryon, meson, lepton, or exchange boson.

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

Explain why charge conservation alone is not enough to decide whether a particle reaction is allowed.

A particle has baryon number \(+1\) and is made of quarks. What family is it in?

A particle has lepton number \(+1\) and no quark content. What broad classification is most likely?

Why do antiparticles have the same rest mass as their particles?

Use baryon number to explain why a proton cannot simply decay into a positron and a photon in the Standard Model.

A reaction has one proton initially and only mesons finally. What baryon-number issue arises?

Find the charge and baryon number of an antibaryon made from \(\bar u\bar u\bar d\).

Why are neutrinos placed with leptons even though they are neutral?

A final state contains a baryon-antibaryon pair. What is the net baryon number of the pair?

Explain why particle families are useful in predicting unknown particles.