Mass gap in Yang-Mills theories

[Chronos]

Is there actually any missing mass? I don't think so. Yang-Mills suggests a slight CPT violation, but no missing energy [mass] that I can see. No matter how much you twist and turn space time around, mass does not go away. The observational evidence for its existence is fairly solid.

 

[ohwilleke]

Is there actually any missing mass? I don't think so. Yang-Mills suggests a slight CPT violation, but no missing energy [mass] that I can see. No matter how much you twist and turn space time around, mass does not go away. The observational evidence for its existence is fairly solid.

The mass isn't missing from the observational universe. The mass is missing from the theory. The gap is between the presence of mass in the observational world, and the absence of mass in the theory, not the other way around. The issue is how to get mass into the theory (with a Higgs like mechanism a possible solution) so that it can fit what we observe, because expect for the mass problem Y-M does a good job of giving us to QCD that we observe.

 

[Lester]

You can find a simple definition of http://en.wikipedia.org/wiki/Mass_gap" . A Yang-Mills theory, in the limit of the coupling gauge going to infinity, displays at the classical level a mass gap. This because there is a theorem proved in

http://arxiv.org/abs/0709.2042 (appeared in Physics Letters B)

http://arxiv.org/abs/0903.2357 (appeared in Modern Physics Letters A)

that maps classical solutions of a massless quartic scalar field on the Yang-Mills field. These solutions appear to describe free massive fields notwithstanding we started from massless theories. One can use these solutions to build a quantum field theory and obtain an identical situation once is proved that quantum corrections do not modify it.