Energy Source of E Field in Decay of Neutral Pi Mesons?

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cragar
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Suppose I have a large wall of neutral pi mesons, a lot of particles in a plane . And they decay into electron positron pairs and move in opposite directions to conserve momentum.
Now we have created an E field in between the particles going from plus to minus. Now we have a parallel plate capacitor . As the particle move apart we are creating E fields in space were they didn't use to be and this takes work. Where is this energy coming from. Does all this energy just come from the pi meson?
 
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Er... I'm not sure why you have to invoke such exotic process. How about electrons emitted from a metallic surface in a photoelectric effect? When it is emitted, there's an image charge on the surface that has an opposite charge to the electron. Same thing.

Zz.
 
Thanks for your response, So all the energy comes from the incoming photon that ejected the electron .
 
cragar said:
Where is this energy coming from.

As the electrons and positrons move apart, their speed decreases because they are attracting each other. They lose kinetic energy, which gets converted to potential energy stored in the field.