An overview of $XYZ$ new particles

Abstract

In the past decade, more and more charmoniumlike and bottomoniumlike states have been reported in experiments, which have led us to extensive discussions on the underlying structure of these states. In this review paper, we briefly summarize the experimental and theoretical status of these observed states.

Comments: Invited review for Chinese Science Bulletin. 14 pages, 4 tables, 3 figures. More reference added