Towards understanding broad degeneracy in non-strange mesons
arXiv:hep-ph/0701089 · doi:10.1142/S0217732307024024
Abstract
The spectroscopic regularities of modern empirical data on the non-strange mesons up to 2.4 GeV can be summarized as a systematic clustering of states near certain values of energy. It is getting evident that some unknown X-symmetry triggers the phenomenon. We review the experimental status of this symmetry and recent theoretical attempts put forward for explanation of broad degeneracy.
Brief review, 16 pages, 1 figure