Baryon number

Definition

Baryon number is a quantum number representing the difference between the number of baryons and antibaryons in a system. It is conserved in most particle interactions, meaning the total baryon number remains constant.

5 Must Know Facts For Your Next Test

1. Baryon number is defined as $B = \frac{1}{3}(n_q - n_{\bar{q}})$, where $n_q$ is the number of quarks and $n_{\bar{q}}$ is the number of antiquarks.
2. Protons and neutrons each have a baryon number of +1.
3. Antiprotons and antineutrons each have a baryon number of -1.
4. In any nuclear reaction or particle decay, the total baryon number before and after the process must be equal.
5. Leptons have a baryon number of 0.

Review Questions

• What is the baryon number for a proton?
• How does baryon number conservation apply to nuclear reactions?
• What would be the baryon number of an atom with one proton, one neutron, and no antibaryons?

Related terms

Quark:

A fundamental constituent of matter that combines to form hadrons such as protons and neutrons.

Lepton:

A type of elementary particle that does not experience strong interactions, examples include electrons and neutrinos.

Antibaryon: A particle composed of three antiquarks, having a baryon number of -1.