Hadronic transition form factors from analyticity

B. Kubis (UBonn) / D. Van Dyk (TUM)

Hadronic transition form factors (TFFs) play a crucial role in the determination of Standard Model
parameters from data and for probing potential effects of physics beyond the Standard Model
(BSM). At the same time, they also contain dynamical information about the inner structure of the
hadrons in question. In principle, TFFs can be calculated ab initio and with great precision using
lattice QCD. However, presently and for the immediate future this is not the case for hadronic TFFs
of non-local operators, or when hadronic final-state interactions and rescattering effects are
important for TFFs of local operators. In such cases, we can use the analyticity properties of the
hadronic TFFs and relate them to other and simpler known hadronic matrix elements using
standard techniques, such as e.g. hadronic dispersion relations. In this project we aim to improve
the descriptions of hadronic TFFs arising in two distinct fields of particle physics: low-energy decay
and transition processes, and (semi)leptonic B meson decays.