Periodic Reporting for period 1 - XXQCD (Excited and exotic hadron resonances from Quantum Chromodynamics)
Reporting period: 2017-06-30 to 2019-06-29
The new ideas developed by this project will improve calculations in lattice QCD that investigate how particles interact as they collide in experiments and form short-lived excitations. The overall objective is to investigate recently discovered short-lived excitations seen in experiments creating a pairing of a charm quark and anti-quark known as charmonium. These new excitations, labelled the X, Y and Zs do not fit into the simplest models which described how a charm quark and anti-quark should interact. This inability to accommodate these new discoveries in a simplified approach suggests the quark and gluon fields inside these states exhibit more complex, exotic behaviour. This behaviour should however be predicted by a full treatment of the strong interactions using QCD and the project objective is to develop the necessary techniques to perform these calculations using lattice QCD.
The action terminated early as the research fellow takes up a new role. During the project, significant progress towards the goals and objectives were made and the research and collaboration developed during the span of the project will continue beyond the lifetime of the action."
The project then moved on to investigating how mesons made of both a heavy charm quark and light anti-quark interact. The relevant lattice QCD calculation probed how the D and D_s meson interact with the pions and kaons studied in the earlier phase. This work is on-going and experience gained over the duration of this project is proving invaluable to future progress. New ideas for investigating the spectrum of states formed by bottom quarks are being developed, again with the work carried out in this project being exploited to guide future research directions.
The knowledge exchange between the incoming fellow and the host institution has been substantial given the shortened duration of the project. The fellow has made significant contribution in training postgraduate early-stage researchers as they develop their projects and this transfer of knowledge directly illustrates one wider societal benefit of basic research of this type.