Key Stage 5
Meaning
Antiparticles are small units of antimatter.
About Antiparticles
- Many particles of matter have antimatter counterparts which have the same mass but opposite electrical charge.
- During pair-production a particle and its antiparticle appear.
- When a particle meets its antiparticle they annihilate one another producing a pair of photons.
- Most antiparticles are given the name of their counterpart particle with the addition of the prefix anti. However, the antiparticle counterpart of the electron is known as the positron.
| Antiparticle | Composition | Charge/e | Strangeness | Baryon Number | Lepton Number |
| \(\bar{u}\bar{u}\bar{d}\) | \(Q=-1\) | \(S=0\) | \(B=-1\) | \(L=0\) | |
| \(\bar{u}\bar{d}\bar{d}\) | \(Q=0\) | \(S=0\) | \(B=-1\) | \(L=0\) | |
| Fundamental | \(Q=+1\) | \(S=0\) | \(B=0\) | \(L=-1\) | |
| Fundamental | \(Q=0\) | \(S=0\) | \(B=0\) | \(L=-1\) |