摘要：

The spectrum of hadrons is the manifestation of color confinement of quantum chromodynamics. Hadronic resonances correspond to poles of the S-matrix. Since 2003, lots of new hadron resonant structures were discovered in the mass regions from light mesons to hadrons containing a pair of a heavy quark and an antiquark. Many of them are candidates of exotic hadrons, and they are usually observed as peaks in invariant mass distributions. However, the S-matrix also has kinematical singularities due to the on-shellness of intermediate particles for a process, such as two-body thresholds and triangle singularities, and they can produce peaks as well. On the one hand, such singularities may be misidentified as resonances; on the other hand, they can be used as tools for precision measurements. In this talk, I will the threshold cusps and triangle singularities in hadronic reactions, paying attention to their manifestations in phenomena related to exotic hadron candidates.
Ref: Feng-Kun Guo, Xiao-Hai Liu, Shuntaro Sakai, Prog. Part. Nucl. Phys. 112 (2020) 103757 [arXiv:1912.07030]

报告人简介：

郭奉坤，中国科学院理论物理研究所研究员。2002年本科毕业于山东大学，2007年在中科院高能物理研究所获得博士学位，随后在德国于利希研究中心以及波恩大学从事博士后研究工作，并担任德国DFG项目负责人。2015年加入理论物理研究所。主要从事强子谱、有效场论等方面的研究工作。

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