# Decay of K+ Meson

In Griffiths Introduction to Elementary Particles we are asked to draw the Feynman diagram for The decay of The $K^{+}$ Meson into a photon, antimuon and muon-neutrino. I am confused by the Diagram in the solution which seems to be completely false as the photon is just a virtual particle and the K Meson is nowhere to be found. Am i missing something here?

The Solution from the Solution Manual:

The solutions manual seems to have an error, you can check on the author's page if this has been corrected. The correct diagram for $K^+ \to \mu^+ \nu_\mu$ is:
In order to get the diagrams for $K^+ \to \mu^+ \nu_\mu+\gamma$, you can take this diagram and attach a photon to any charged line (any line except the neutrino).
• There's a line that says: Corrections to the ISM have been incorporated into the current electronic version, here I believe ISM refers to "Instructor's Solution Manual." The online version of the instructor's manual should have this incorporated. – Henry Deith Aug 24 '17 at 20:34