To me this is the most important question in physics. Of course, interactions are exchanges of gauge bosons. But what is happening? How do the exchanges take place?
In the past weeks, I read everything I could find about this topic. A sobering experience that I can summarize thus: white, English-speaking men know nothing about the answer. And they are even afraid of speculating about it. Other humans do not write anything about it.
Wikipedia's article http://en.wikipedia.org/wiki/Fundamental_interaction is funny: "fundamental interactions are the ways that elementary particles interact with one another". One has to be drunk to write such a definition.
Most researchers only say that interactions are "particle exchanges described by a gauge group". They speculate about various gauge groups, or about supersymmetry, or about BRST. But no one speculates about how interactions appear in the first place.
Established researchers do not explore the question. But why? They do not even speculate about it. Are they afraid? I only found the spaghetti model as candidate proposal. What a poor harvest. And of course, it is written by a white, English-speaking man. What about black women speaking Swahili? Or South-American women speaking Quechua? And what shall we do before they come along?
One friend told me about a possible background. She said that white men are so nasty among each other that anybody daring to speculate is not invited any more to talks, to committees or to conferences. "Speculators" are discarded from the academic community. They know it and they fear it. They behave among themselves in the same way that they behave towards students in examinations.
Men have organized modern physics in a way that speculation has become impossible. Progress is impossible in modern theoretical physics. Dear sisters, please come along!