Yang–Mills theory and mass gap

Question

I am interested in widening my knowledge into the formal aspects of Yang–Mills theory. In particular, I would like to study the current mathematical and physical research literature about this argument and about the 'Yang–Mills existence and mass gap' problem which is phrased as follows:

Prove that for any compact simple gauge group $\rm G$, a non-trivial quantum Yang–Mills theory exists on $\mathbb {R} ^{4}$ and has a mass gap $\Delta > 0$.

The literature about this argument is wide and complex. Is there anyone who may suggest me some introductory paper? Maybe a review of the state of art. Consider that I have quite good basis in functional analysis and about quantum field theories from a point of view of mathematical physics (as regard the latest point). I would thank you if you can indicate me also more advanced papers so that I can have an idea of the current state of the art about this topic once I will have finished the introductory review(s).

Thank you in advance if you can help me,

Kel

Answer 1

I don't know whether you've done this already, but the natural thing to do seems to be to read the official statement of the problem and its status.

Answer 2

You can find a useful survey in these recent talk slides by Sourav Chatterjee.