Title: Threshold effects as the origin of several newly observed exotic hadrons  

Speaker: Dr. LIU Xiaohai 

Time: 10:00am, Mar.24 (Wednesday), 2021 

Place: Room 1006, Building 5 

Abstract:  

There have been many theoretical interpretations concerning the nature of those exotic hadron candidates observed in recent years, such as molecular states, multiquark states, or hybrid. Apart from these genuine resonances interpretations, some non-resonance interpretations were also proposed in the literature. The threshold effects, such as the threshold cusp and triangle singularity of the amplitude, can also result in some resonance-like structures in the pertinent invariant mass spectrum, therefore sometimes it is not necessary to introduce a genuine particle to describe a resonance-like peak. The kinematic singularities may simulate genuine resonances, which will bring ambiguities to our understanding of the nature of exotic states. Before claiming that one resonance-like peak corresponds to one genuine particle, it is also necessary to exclude or confirm these possibilities.