Speaker
Description
The progress on the so-called proton radius puzzle has been impressive in recent years. Corresponding advances for unstable baryons such as hyperons are more challenging to achieve, but are eagerly awaited: they would reveal the role of flavour in the strong interaction dynamics governing the femtometer structure of hadrons. Due to the short hyperon life-time, most methods that have been developed and utilized successfully for structure studies of nucleons, are not applicable. However, hyperons being unstable is not only a challenge but also a blessing: in weak, parity violating decays, features such as spin polarization and quantum correlations become experimentally accessible. This is in contrast to nucleons, for which dedicated polarimeter detectors are needed for this purpose. From the experimentally accessible spin properties, the full, complex time-like form factors can be extracted, which in turn give information about space-like quantities such as the charge radius.
The BESIII experiment at the electron-positron collider BEPC-II in Beijing, China, has performed a series of pioneering hyperon structure measurements through dedicated energy-scan campaigns. In my talk, I will present the results that have emerged from BESIII in the recent years, and discuss the next steps in our journey towards a more coherent understanding of hadron structure.
