# Anti-matter and matter annihilation

## Summary:

Does anti-matter and matter annihilate each other even if they are not same "type" (eg. neutron and positron) and they meet each other?

## Main Question or Discussion Point

Does anti-matter and matter annihilate each other even if they are not same "type" (eg. neutron and positron) and they meet each other?

## Answers and Replies

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Orodruin
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No.

However, that does not mean other reactions are not possible. In your particular case you can have $n + e^+ \to p + \bar\nu_e$.

mfb
Mentor
It depends on what meets what. Both antiprotons and antineutrons will react with both protons and neutrons in any combination, individually or in nuclei doesn't matter. The most likely result of that reaction is a couple of pions.

Orodruin
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There is also the issue of what is meant by ”annihilation”. A common misconception from popular literature seems to be that particle-antiparticle pairs somehow annihilate ”to energy”. However, energy is not a thing in itself but a property of physical objects such as particles. In the most publicized case of electron-positron annihilation, the energy is converted to photons, but generally this is not the only possibility.