# M2: Milestones second funding period

• Analysis of the various data sets of BESIII above 4.1 GeV/c2 center of mass energy by one simultaneous fit to the data. This will be performed for the two reaction channels Y →  J/ψπ+π- and Y → DD̅*. In order to achieve this goal, the Common Partial Wave Analysis Framework ComPWA, developed and maintained by the Helmholtz Institute Mainz, will be extended to allow for these simultaneous fits.
• A search for the isospin singlet states decaying to J/ψη and ηcη will be performed.
• A detailed investigation of the structures in the D recoil spectrum will be performed.
• The full BESIII data sets taken on the \jpsi and \psip resonances will be analyzed to derive input data for an amplitude analysis of the decays to \pions. Starting from a simple isobar analysis, we will test more advanced models involving e.g. rescattering effects.
• Analysis of ω → \piz \epem, ω → ηγ with A2 data.
• Dalitz plot analysis of $\etapr \to 3 \piz$ with A2 data.
• Consistent quantum-field theoretical description of the PVγ system. By extending Dirac's Hamiltonian method to also include interactions with pseudoscalars and by combining it with renormalizability in the sense of effective field theory, we will derive constraints for the coupling constants of the most general Lagrangian. The unstable nature of vector mesons will be treated in the framework of the complex-mass scheme.
• Quantum corrections to the chiral anomaly in the processes η' → π+π-γ and η'→ ππγ, making use of the recently developed ηη' mixing scheme.
• We will organize a workshop together with project S3 in which common partial wave analysis techniques will be discussed.