A deuteron d is a combination of two nucleons in an isospin-0 state. (Think: How is this different from saying that a deuteron is made up of one proton and one neutron?) Two deuterons collide with...

A deuteron d is a combination of two nucleons in an isospin-0 state. (Think: How is this different from saying that a deuteron is made up of one proton and one neutron?) Two deuterons collide with each other at high speed and interact via the strong nuclear force. Here is the net reaction:

d + d → d + d + pions.

The pions produced, of course, must have zero total electric charge.

(a) Is it possible to produce a single pion? Why or why not?

(b) The reaction might produce two π⁰s or a π⁺π− pair. Find the ratio of the probabilities for these two processes.