报告人：郭奉坤 研究员 （中科院理论所）
报告时间：2021年5月13日 （周四）15:30-16:30
报告地点：32教256室（腾讯会议ID：375 3347 0839）
报告题目：Towards a general understanding of near-threshold structures in heavy-hadron spectrum
报告摘要：
Tremendous progress has been made experimentally in the hadron spectrum containing heavy quarks in the last two decades. It is surprising that many resonant structures are around thresholds of a pair of heavy hadrons. By constructing a nonrelativistic effective field theory with open channels, we discuss the generalities of threshold behavior, and offer an explanation of the abundance of near-threshold peaks in the heavy quarkonium regime. We show that the threshold cusp can show up as a peak only for channels with attractive interaction, and the width of the cusp is inversely proportional to the reduced mass relevant for the threshold. We argue that there should be threshold structures at any threshold of a pair of heavy-quark and heavy-antiquark hadrons, which have attractive interaction at threshold, in the invariant mass distribution of a heavy quarkonium and light hadrons that couple to that open-flavor hadron pair. The structure becomes more pronounced if there is a near-threshold pole. Then, to get an overall feature of the spectrum of hadronic molecules composed of a pair of heavy-antiheavy hadrons, namely, which pairs are possible to form molecular states, we approximate the near-threshold interaction by the resonance saturation with the light-vector exchanges. In total, 229 molecular states are predicted. The observed near-threshold structures with hidden-charm, like the famous X(3872) and Pc states, fit into the spectrum we obtain. Lots of the predicted states are to be explored experimentally.
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年博士毕业于中国科学院高能物理研究所。2007-2010在德国于利希研究中心做博士后，2010-2015在波恩大学做博士后，期间担任中德国际合作项目 CRC110中两个子项目的德方PI。2015年获国家人才计划资助回国，任中科院理论所副研究员，2019年1月任研究员。郭奉坤研究员主要从事粒子物理理论研究，研究方向涉及强子谱学、与格点QCD计算相关的有效场论、强CP破坏与theta真空、电弱对称破坏的有效场论等。共发表SCI论文120余篇，其中包含12篇PRL文章，1篇RMP综述，1篇PPNP综述，总引用近7000次，h指数44。曾于2019年获得“胡济民教育与科学奖”。
视频链接：
https://www.bilibili.com/video/BV1mB4y1F71w
