Dynamical Correlations in Double-Photon Emission and Double-Beta Decay in Atomic Nuclei

• Applicant: Professor Dr. Horst Lenske
• Subject Area: Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields ; Theoretical Condensed Matter Physics
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 539381160

Theoretical investigations of dynamical correlations in higher order electro-weak and hadronic processes in nuclei and nuclear reactions are proposed. The scope of the project is to explore and develop theoretical methods for the improved description of many-body dynamics common to the nuclear matrix elements (NME) of higher order nuclear processes in electromagnetic and weak decays, and eventually in hadronic reactions. The investigations will be done in parallel for infinite matter and finite nuclei. The infinite matter studies will serve as reference to identify the universal features and global properties of polarization dynamics and the dependencies on density and charge asymmetry. The applications to finite nuclei will reveal size- and shape-dependent variations and dependencies on shell effects. In all (numerical) studies the microscopically derived Giessen energy density functional (GiEDF) will be used for mean-field and residual interactions in 1st and 2nd variation of the EDF with respect to densities and currents. The role of ground state correlations on the Hartree-Fock-Bogoliubov (HFB) mean-field, pairing field, single particle states, total nuclear binding energies and radii will be studied. The updated quasiparticle spectrum will be used in Quasiparticle Random Phase Approximation (QRPA) and in Extended Quasiparticle Phonon Model (EQPM) studies of polarization tensors and related NMEs of electromagnetic and weak processes, entering also into the theory of Double Charge Exchange (DCE) reactions. In perspective, the investigations are planned to be extended to the full polarization propagators playing a key role in the theory of DCE reactions with pion and heavy ion beams. The final goal is to clarify the largely unexplored effects of dynamical correlations in 2nd order nuclear processes with special attention on burning questions on the physics of double-gamma and double-beta decay.

• DFG Programme: Research Grants
• International Connection: Romania
• Cooperation Partner: Dr. Nadia Larionova-Tsoneva