Studies of discrete symmetries in eta' meson decays and the electromagnetic form factors of hyperons at BESIII

  • Date: –11:30
  • Location: Zoom
  • Lecturer: Viktor Thorén (Uppsala University)
  • Contact person: Rebeca Gonzalez Suarez
  • Seminarium

This will be a virtual seminar, and will be hosted in Zoom


Meeting ID: 666 6207 4599

Half-time PhD seminar

At the precision frontier of particle physics, much can be learnt from studying hadrons and their decays. They offer a window into many of the as yet unanswered questions of fundamental physics; Why is there more matter than antimatter in the universe? And how do the properties of the fundamental constituents of matter come about?

To this end, the BESIII (Beijing Spectrometer) experiment in Beijing, China has been collecting large and diverse data samples from e+e- collisions since 2008 with the world's largest sample at the J/psi mass as its crowning achievement. In this talk, I will present two analyses of data from the BESIII experiment conducted as part of my PhD.

The first deals with the rare decay of the pseudoscalar meson eta' into pi+pi-e+e-. This decay may exhibit a contribution from a non-standard model CP-violation which would manifest itself as an asymmetry in the angle between the decay planes of the e+e- and pi+pi- pairs. Using data at the J/psi mass we measure this CP-asymmetry for the first time.

The second analysis concerns the electromagnetic structure of hadrons as described by electromagnetic form factors. The electromagnetic form factors of nucleons have already been studied extensively, but by investigating their strange relatives, the hyperons, we can gain new and complementary information. Using a method that combines fully and partially reconstructed events, we measure the electromagnetic form factors of the Lambda hyperon at several center-of-mass energies between 2.3864 and 2.9 GeV.