Further backing secured for German role in Mu3e particle physics project

Further backing secured for German role in Mu3e particle physics project
by Robert Schreiber
Berlin, Germany (SPX) Apr 10, 2025

Scientists at Johannes Gutenberg University Mainz (JGU) will continue their involvement in the cutting-edge Mu3e experiment thanks to renewed financial support from the German Research Foundation (DFG), which has pledged an additional EUR 5.6 million in funding starting May 2025. This grant extends the Research Unit 5199 for another four years, allowing the collaboration to push further in its investigation of lepton family number violation.

The Mu3e experiment is hosted at the Paul Scherrer Institute (PSI) in Villigen, Switzerland, and brings together an international consortium of researchers from Germany, Switzerland, and the United Kingdom. The central objective is to detect a rare and theoretically forbidden decay of a positively charged muon into two positrons and one electron. Such an observation would defy the predictions of the Standard Model and point toward new physics.

Currently, the experiment is undergoing commissioning following the initial funding phase. The team is implementing high-precision detection technologies, including ultrathin HV-MAPS pixel sensors, along with scintillating fibers and tiles, to enable detection of rapid decay events. In its first operational stage, the Mu3e setup will handle a beam intensity of up to 100 million muons per second. A planned upgrade by 2027 will introduce a High-Intensity Muon Beamline, dramatically boosting the decay observation rate to a staggering 10 quadrillion events.

The DFG's decision to extend support for the Research Unit "Searching for charged lepton flavor violation with the Mu3e experiment" (FOR 5199), which unites teams from Mainz, Heidelberg, and Karlsruhe, follows a positive evaluation of the unit's performance. The renewed funding ensures the continuation of the experiment through its initial data collection, commissioning phase, and preparations for future experimental enhancements.

At Mainz, the group led by Professor Niklaus Berger, part of the PRISMA+ Cluster of Excellence, has taken the lead in developing the experiment's power distribution and data acquisition systems. The team is actively preparing the apparatus for operation and has started analyzing preliminary datasets. Looking ahead, they are also designing methods to accommodate data volumes expected to be up to 20 times higher in the next experimental stages.