# Why doesnt neutron scattering violate charge conservation?

1. May 19, 2014

### rwooduk

p + n -> p + n + ∏^-

check charge conservation:

+ 1 + 0 = +1 + 0 -1

it doesn't equal so it wouldn't be possible? please could someone suggest why this is, or if i'm doing something wrong?

edit is it because the pion is the force carrier therefore should not be included in the reaction and check above?

2. May 19, 2014

### kjhskj75

No it's because the pion is absorbed on the right hand side and is not part of the final configuration.

You just have p + n -> n + p which conserves charge

Or you can split it into two interactions:

n -> p + $\pi$- and then p + $\pi$- -> n

both of which conserve charge

3. May 19, 2014

### rwooduk

explains it perfectly, many thanks!