Particle–Antiparticle Pair Calculator
Look up rest mass, charge, and annihilation products of particle–antiparticle pairs. See the energy released per pair.
Choose Pair
Symbol:e⁻ / e⁺
Rest mass:0.511 MeV/c²
Charge:∓1 e
Spin:½
Total annihilation energy
0.000 J
1.022 MeV
Annihilation Details
Energy per pair1.022 MeV
Mass converted (total)1.822e-30 kg
Primary products2 photons (γ-rays @ 511 keV each)
Reference Table — Common Particle–Antiparticle Pairs
| Pair | Rest mass (MeV/c²) | Charge | Energy per pair |
|---|---|---|---|
| Electron / Positron (e⁻ / e⁺) | 0.511 | ∓1 e | 1.022 MeV |
| Proton / Antiproton (p / p̄) | 938.272 | ±1 e | 1,876.544 MeV |
| Neutron / Antineutron (n / n̄) | 939.565 | 0 e | 1,879.13 MeV |
| Muon / Antimuon (μ⁻ / μ⁺) | 105.66 | ∓1 e | 211.32 MeV |
| Tau / Antitau (τ⁻ / τ⁺) | 1,776.86 | ∓1 e | 3,553.72 MeV |
| Neutrino / Antineutrino (νₑ) (νₑ / ν̄ₑ) | 0 | 0 e | 0 MeV |
About Pair Annihilation
When a particle meets its corresponding antiparticle, the two are completely converted into other particles — typically photons (gamma rays) for leptons, or showers of pions for baryons. Conservation laws ensure that the total energy, momentum, charge, and lepton/baryon number of the products equal those of the incoming pair.
Common annihilation channels
- e⁻ + e⁺ → 2γ — each photon carries 511 keV. This is the basis of PET (positron emission tomography) imaging.
- p + p̄ → mesons — typically several pions, which decay into muons, electrons, neutrinos, and gamma rays.
- n + n̄ → mesons — similar to p + p̄, with charged and neutral pions dominating.
- ν + ν̄ — extremely rare via Z boson exchange; cross-section is tiny.