# Can a gamma initiate weak decay of a proton?

1. ### Philip Wood

1,099
Does this ever happen?

p + $\gamma$ $\rightarrow$ n + e+ + $\nu_e$

It seems possible, if the $\gamma$ has enough energy, but I wonder if anyone can confirm that it happens.

Last edited: Sep 22, 2011
2. ### PAllen

5,425
While I have no idea of whether this could happen in practice, or what the cross section would be, I don't see anything to fundamentally prohibit it. In fact, it strikes me you could look at this as combining two well known interactions that do occur:

p + gamma -> p + e+ + e-

then, electron capture. Combine, and you get the proposed reaction. This supports the view that there shouldn't be anything fundamental prohibiting this.

3. ### Philip Wood

1,099
Thank you. This does indeed make it seem even more plausible.