Chair of Prof. Ulmer/Dr. Smorra – Quantum Technologies and Fundamental Symmetries

Why does our universe contain more matter than antimatter? At the BASE collaboration, led by our laboratory at CERN’s Antiproton Decelerator and ELENA facility, we’re tackling this fundamental mystery through some of the most precise experiments ever performed.

By comparing the fundamental properties of protons and antiprotons with record-breaking accuracy, we put the very foundations of physics—such as charge, parity, and time-reversal (CPT) symmetry—to the test. Our measurement of the proton-to-antiproton charge-to-mass ratio, accurate to 16 parts per trillion (Nature, 2022), is the most sensitive test of CPT symmetry in the baryon sector to date. We’ve also compared their magnetic moments at 1.5 parts per billion precision (Nature, 2017), pushing the boundaries of matter-antimatter symmetry tests.

These breakthroughs are powered by world-leading innovations: ultra-stable cryogenic Penning trap systems, antiproton reservoirs that can store particles for years (Nature), and detection technologies operating at the quantum limit. Our traps achieve the lowest known quantum heating rates (PhyRevLett,2019) and the highest magnetic gradients ever used—enabling us to search for physics beyond the Standard Model. For example, we’ve placed some of the tightest constraints yet on exotic phenomena like millicharged dark matter (PRXQuantum, 2022) and asymmetric matter-dark matter couplings(Nature, 2019).

Now, we're going one step further. With our new BASE-STEP project, we’ve successfully transported protons out of CERN’s antimatter factory—paving the way for precision antimatter studies in quiet, low-noise labs far from the accelerator. At Heinrich Heine University Düsseldorf, we're building such a laboratory now, aiming to push the accuracy of our measurements even further.

This isn’t just particle physics—it’s a journey into the deep structure of reality.