Project Details
Projekt
The confined gluon: radiative decays of charmonium
Applicant
Professorin Dr. Sara Collins, Ph.D.
Subject Area
Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields
Term
since 2026
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 451886959
In the last twenty years, an impressive array of hadrons have been discovered in experiments worldwide, a number of which do not fit into a simple quark model picture in terms of their quark and gluon constituents. The masses and structure of hadrons arise from quantum chromodynamics~(QCD) and many configurations of quarks and gluons are possible, including meson-meson molecules and states with a significant gluonic component, such as glueball-like mesons. A prime production mechanism for glue-rich states is through the radiative decays of charmonia. Glueball candidates with scalar and pseudoscalar quantum numbers have been observed in such decays. The masses of these states lie close to predictions from lattice QCD for the pure gauge theory, however, in nature, the presence of sea quarks means there is mixing between glueball and quark-antiquark configurations, complicating the interpretation of experimentally observed structures. Rigorous theory predictions of the radiative decay rates are needed to compare with experiment. However, this is only possible through advances in calculational methods. The main objectives of this project are to investigate radiative decays of charmonia to light flavour-singlet mesons, including glueball-like resonances using lattice QCD. We will also compute the radiative transition form factors between different narrow charmonia, which will provide insight into the internal structure of these mesons. The correlation functions associated with many of these radiative decays suffer from a poor signal to noise ratio as the time separations increase. Novel features of the project include the implementation and further development of multi-level noise reduction techniques and tuning the pion mass of the theory to reduce the number of strong decay modes that are open for glueball-like resonances.
DFG Programme
Research Units
International Connection
Ireland
Cooperation Partner
Professor Dr. Michael Peardon
