The Cosmic Antimatter Puzzle

Moments after the Big Bang, matter and antimatter were created in equal amounts and mostly destroyed each other. Yet a small surplus of matter remained. This leftover matter forms the universe we know today, with its stars, planets, and galaxies. What caused this imbalance is one of the biggest mysteries in physics. In search of an explanation, scientists carefully compare the properties of matter and antimatter, such as the mass and magnetic properties of electrons, protons, and their antiparticles. Using precision experiments with trapped and cooled ions, they study these differences in detail, searching for tiny asymmetries that could explain why matter still exists.

Physicist Klaus Blaum heads the Stored and Cooled Ions department for Nuclear Physics in Heidelberg. The experiments he's talking about are being conducted at CERN, Geneva, Switzerland. In this Hendrik de Waard lecture, he presents precision experiments with stored and cooled ions in so-called Penning traps and asks whether protons and antiprotons truly have identical mass. Could tiny differences explain why anything exists at all?

Klaus Blaum is an experimental physicist known for developing high-precision Penning-trap methods to study exotic nuclei, enabling stringent tests of the Standard Model and advancing our understanding of nuclear structure and astrophysical processes. He studied physics at Johannes Gutenberg University Mainz, completed his PhD in 2000, and then worked at CERN in Geneva. After leading a Helmholtz research group (2004–2007), he became director of the “Stored and Cooled Ions” department at the Max Planck Institute for Nuclear Physics and professor at Heidelberg University. Among many honors, he received the Stern Gerlach Medal in 2025 and the Gottfried Wilhelm Leibniz Prize in 2026.

This lecture is organised by the Hendrik de Waard Foundation in collaboration with Studium Generale Groningen. The Hendrik de Waard Foundation was founded after the retirement of the late professor of physics Hendrik de Waard in 1987. Annually, the foundation organises a lecture to inform and intrigue the general public about recent developments in science.