Search for non-conventional hadron states is one of major physics goals in many experiments in the past 40 years. The claims of penta-quark Theta+ by many experiments around year of 2004 drew great attention but later results with high statistics data didn’t support those claims. In recently, charmonium-like states Zc(3900)/ Zc(4020) observated by BESIII were claimed to be tetra-quark states，Pc(4380)/ Pc(4450) observated by LHCb were claimed to be penta-quark ) states. In addition, WASA also claimed the discovery of d*(2380) as a dibaryon state (hex-quark state). I would like to give a global review and discussion on those discoveries and also a bit more details on the observation of charmonium-like neutral Zc via open DD* and D*D*.

Yajun Mao, Professor of Physics at School of Physics in Peking University. He has been the Head of Department of Technical Physics since 2016 and was former cospokesperson and IB chair of BESIII Collaboration. His main research interests are hadron spectroscopy physics in BESIII experiment and Electro-Weak physics in CMS experiment.