Seminar Announcement Date: Thursday, 14 December 2023 Time: 11:30 AM Venue: Lecture Hall 01 Born-Oppenheimer Effective Theory for Exotic Quarkonium Hybrids (Exotic XYZ mesons) Abhishek Mohapatra Technical University, Munich, Germany. 14-12-23 Abstract Over the past two decades, numerous exotic XYZ mesons (around 30 of them) have been discovered, which poses a major challenge to the understanding of the spectrum of Quantum Chromodynamics (QCD). These states are bound states involving heavy quark-antiquark or heavy quark quark pairs. There are multiple interpretations for these XYZ mesons. However, none of these models provide a clear understanding of the nature and pattern of these states based on QCD. One of the many interpretations of these XYZ exotic mesons is Quarkonium hybrids. In my talk, I will discuss how the quarkonium hybrid states can be addressed in the nonrelativistic effective theory (EFT) framework: Born-Oppenheimer effective theory with inputs from lattice QCD. Based on this EFT framework, I will discuss the computation of the semi-inclusive decay rates of heavy quarkonium hybrids into conventional heavy quarkonia. The decay rates are computed at leading and subleading power in the inverse of the heavy-quark mass. Based on the decay rates, we will rule some of the XYZ mesons as hybrid candidates. Towards the end, I will briefly discuss the future plan which includes the BOEFT formalism extension for tetraquarks and pentaquarks as well as computing hybrid decays to meson pair thresholds
|