Why Do Matter-Antimatter Pairs Annihilate Instead of Sticking Together?

[quantumkiko]

Why does an matter-antimatter pair annihilate each other instead of "sticking" together (i.e. like ordinary matter with opposite charges do)?

 

[Physics Monkey]

In fact, they don't always annihilate right away. For example, an electron and a positron may form a bound state called positronium. Positronium doesn't live forever, but a certain form of it can live for a relatively long amount of time, more than 100 nanoseconds! That may not sound like much, but it does show that matter and anti matter don't have to immediately annihilate.

http://prl.aps.org/abstract/PRL/v90/i20/e203402
http://physicsworld.com/cws/article/news/17559
http://en.wikipedia.org/wiki/Positronium

Hope this helps.

 

[Bob S]

A relativistic positron can annihilate in flight with an atomic electron in matter. The integrated probability for a 50-MeV stopping positron is ~ 15%. See pages 384-6 in Heitler "The Quantum Theory of Radiation" Fourth Edition.
Bob S

 

[quantumkiko]

Thank you very much for the feedbacks! I appreciate it. =)