Hyperonsönderfall inom BESIII och PANDA-experimenten – sällsamma nycklar till fundamentala krafter och symmetrier

Karin Schönning. Photo: Mats Kamsten.

The Swedish Research Council reached a decision on October 31, 2019 on project grants and starting grants for Natural and Engineering Sciences. The Department of Physics and Astronomy is granted 40 840 000 SEK for the period 2020-2023 for in total nine project grants and three starting grants. The projects will begin during 2020.

Project description

Project title: Hyperonsönderfall inom BESIII och PANDA-experimenten – sällsamma nycklar till fundamentala krafter och symmetrier
Main applicant: Karin Schönning, Division of Nuclear Physics
Grant amount: 3 825 000 SEK for the period 2020-2023
Funder: Project grant from the Swedish Research Council

This project aims to shed light on two of the most challenging questions in contemporary physics: confinement and the matter-antimatter asymmetry of the Universe. The first refers to why quarks always must be confined into hadrons, i.e. bound systems like protons and neutrons. The second refers to why our Universe is made almost entirely of matter, though an equal amount of matter and antimatter should have been created in the Big Bang. These two problems are connected in the sense that they can both be probed by hyperon decays. Hyperons are similar to the proton and the neutron, but contain at least one heavy quark, e.g. strange or charm.

The inner structure of hyperons can be probed by Dalitz decays, in which an electron-positron pair is emitted. Since the scale of this process coincides with the confinement domain, we can gain insight into why and how quarks form hadrons. I will carry out these pioneering measurements at the PANDA Phase 0 experiment in Germany, launching in 2020.

CP symmetry is when particles and antiparticles follow the same laws but with inverted spatial coordinates. CP violation is necessary to explain the enrichment of matter with respect to antimatter. It also offers a way to search for physics beyond the Standard Model. CP tests can be probed by hyperon decays using data from BESIII in China. A new method, developed in Uppsala, will be applied.

Both measurements are important milestones for the hyperon programme at the future PANDA experiment at FAIR.