Project Details
Projekt
Charmonium Physics Experiments with the BESIII Detector
Applicant
Professor Dr. Ulrich Wiedner
Subject Area
Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields
Term
from 2015 to 2019
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 271236083
The interaction of gluons is a central part of the accepted theory of the strong interaction Quantum Chromo Dynamics (QCD). The self interaction of gluons should lead to the existence of states containing only gluons as constituents, glueballs. From a theoretical point-of-view they are well motivated and e.g. lattice calculations predict a whole spectrum of them with different quantum numbers and masses. Experimentally it is much more difficult to pin down the spectroscopic observation of a resonance as glueball. This is owed to the fact that hadronic resonances often overlap in their widths and mix with each other making the assignment as glueball ambiguous. The situation can be improved by observing resonances in reactions believed to involve mainly gluons. The radiative decay of charmonia into light quarks belongs to this class. The observation of new resonances here and the non-observation in gluon-poor reactions like two-photon processes (see TP Heinsius) would be a strong hint for the gluonic character of the resonance. The high-statistics data from BESIII then allow for a detailed study of glueball decays and investigating them seems currently the only experimental way promising progress. This way, theories dealing with the so far speculative structure of glueballs or describing the hadronization of mesons proceeding via intermediate gluon states could be checked and refined. In order to clearly classify unknown resonances among the always present hadronic background a detailed partial-wave analysis is required. The achievements of the best possible results asks for a close collaboration within the Forschergruppe.
DFG Programme
Research Units
