What's the current state of Yang Mills Mass Gap question, is there any place that does this problem? Especially I want to know if there is any progress (out of that mentioned in the introduction article by Witten and Jaffe). Is it too hard for a mathematician? Thanks!
There's some guidelines about open problems in the FAQ that you might want to read, but there was a good article by Faddeev last November that you should know about:
There is a rather strange situation here because a russian mathematician, Alexander Dynin, is claiming to have solved it. Please, refer to this question of mine or this paper published in a reputable journal. Till now I have not seen any reaction from the community but I think that an analysis of the work of this author is overdue. Indeed, he has worked on this since 2009 as I can see from arxiv.
 Dimitra Karabali and V. P. Nair, Int. J. Mod. Phys. A 12, 1161 (1997) http://arxiv.org/abs/hep-th/9610002
See eqn (20), (21) and the following paragraph.