The Physics
Hypertextbook
Opus in profectus

# Quantum Chromodynamics

## Problems

### practice

1. The mass of the top quark is 173.21 GeV/c2 — heavier than some atoms. Identify the heaviest element that is lighter than the top quark.
2. What fraction of the mass of you and me, the air, earth, oceans, and everything else we deal with in our ordinary lives is due to the strong force?
3. Write something.
4. Write something.

### combinatorics

1. A quark-antiquark pair is called a meson. For example, a positive pion is an up-antidown quark pair (π+ = ud̅).
1. How many mesons can be made from the first generation quarks only?
2. How many mesons can be made from all six flavors of quark?
3. What charges are possible?
2. A triplet of quarks is called a baryon. For example, a proton is two up quarks and one down quark (p+ = uud) while a neutron is one up quark and two down quarks (n0 = udd). Permutations of quarks are considered identical (for example, uds = usd = sud =…).
1. How many baryons can be made from the first generation quarks only?
2. How many baryons can be made from all six flavors of quark?
3. What charges are possible?
3. According to some theoreticians, groups of six quarks may be moderately stable.
1. How many six-quark particles can be made from the first generation quarks only?
2. How many six-quark particles can be made from all six flavors of quark?
3. What charges are possible?
4. Invent an appropriate name for this class of particles.

### investigative

1. top-quark.pdf
The purpose of this activity is to determine the mass of the top quark from proton-antiproton collision data gathered at Fermilab in 1995.