A neutral pion can decay into two photons. It is therefore not unreasonable to ask the question whether the reverse process – the creation of a neutral pion by colliding two photons – is physically possible and, if not, why not? It is perhaps less reasonable to ask an AI bot these questions. One of my colleagues did just that and found it said “no”, giving the following three answers to the “why not?” question:
I particularly like the second one.
Would anyone like to offer a correct answer through the comments box?
In the Dark 