Research Group Berger

High rate precision experiments in particle and hadron physics

We are designing and building high rate experiments to test the Standard Model of elementary particle physics in precision experiments and analysing the resulting data.


  • We are just back from the annual practical course in particle physics, where twelve students from ETH Zürich, Heidelberg and Mainz built and operated their own detector at the worl's most intense proton accelerator at PSI. Have a look at the picture gallery.
  • In a beam time at the MAMI accelerator we are testing MuPix8 sensors and our data acquisition system at very high rates. See the picture gallery.
  • The thermo-mechanical protype for the P2 tracking detector is slowly taking shape; see the picture gallery for the current status and impressions from the lab.
  • Our paper on the efficincy and timing performance of the MuPix7 HV-MAPS prototype was published in Nuclear Instrumentation and Methods. Also availabe on the arxiv.
  • The interdisciplinary symposium 2018 again brought together groups from all over the University of Mainz and presented the fascinating breadth of research at JGU and the many talented Ph.D. students. Have a look at the pictures.
  • We have just submitted our large review paper about the physics and detector of the P2 experiment, see the arXiv.
  • Dorothea vom Bruch from our group has developed and implemented the algorithms for the Mu3e filter farm, showing that just 12 PCs with powerful GPUs are sufficient to reduce over 10 Gbyte/s of data to manageable levels. She also performed detailed studies of the position dependent timing behaviour of the MuPix7 HV-MAPS prototype. She has now successfully defended her thesis in Heidelberg. The thesis is available here.
  • The exhibition ZoomIn on the Mainz Campus shows how detectors are used to make tiny particles visible. It features the Mu3e experiment with a brand new MuPix8 chip.
  • The interdisciplinary symposium 2017 brought together groups from all over the University and presented the fascinating breadth of research at JGU. Have a look at the pictures.
  • Some of our students organised an interactive research symposium on flavour physics. Have a look at the picture gallery for this event, which brough Ph.D. and master students as well as a group of excellent lecturers from all areas of particle physics to Mainz.
  • Picture gallery of the practical course in particle physics we held at PSI in the first two weeks of September 2016.
  • Pictures from our June 2016 high intensity test beam with electrons at MAMI in Mainz.
  • In spring 2016, we met with working groups from all corners of the University for an interdisciplinary symposium - check out the picture gallery.
  • Pictures from our March 2016 test beam with photons at MAMI in Mainz.


Currently, we are involved in three experiments:

Logo P2The P2 experiment at the new electron accelerator MESA in Mainz aims to measure the weak mixing angle in electron-proton scattering with unprecedented precision. Our group is designing and building a fast pixel tracker for this experiment.

BES III LogoThe BES III experiment in Beijing studies electron-positron collisions in the energy range from 2.5 to 4.5 GeV. Our group analyses data from BES in order to understand the meson spectrum, i.e. how the strong nuclear force binds quarks and antiquarks.

Mu3e LogoThe Mu3e experiment searches for the lepton flavour violating decay of a muon to three electrons. For this high precision, high rate experiment we are developing the data acquisition and track reconstruction.


Our involvement in these experiments is based on a set of experimental techniques in which we are continuously developing our expertise:

MuPix ChipHigh Voltage Monolithic Active Pixel Sensors: A new silicon sensor technology allowing for fast and extremely thin pixellated sensors.

FPGA developmentFirmware for data transmission and event selection on Field Programmable Gate Arrays (FPGAs): Acquire, sort, transmit and process Gbits to Tbits of data per second using custom firmware on state of the art programmable electronics and connected multi-GBit/s optical links.

Track recosntructionReconstruction of charged particle tracks is a formidable pattern recognition task in modern high rate detectors. We develop and apply algorithms for fast and accurate track finding, track fitting and detector alignment, both on- and off-line.

GPU ComputoingMassively parallel computing on graphics cards (GPUs) can help solve the computational challenges of fast track and vertex reconstruction and also be used to speed up amplitude analyses.

MuPix TelescopeDetector tests using the MuPix telescope: We have built a four layer track telescope from MuPix pixel sensors which can be used for detector tests up to extremely high rates.

Amplitude AnalysisAmplitude analysis is a core technology to extract the hadron spectrum from collision data, e.g. form the BES III experiment. We are involved in implementing and optimizing novel models in the analysis and applying them to interesting channels in the BES III data.


Nuclear Physics Institue

We are located at the Institute of Nuclear Physics in Mainz, where we have the unique opportunity of using the MAMI electron accelerator for detector tests and will receive the new MESA accelerator driving the beam for P2.

We are part of the PRISMA+ cluster of excellence in Mainz and collaborate closely with the PRISMA detector lab in the design and construction of experiments.


The activities in P2 and BES III are supported by the DFG collaborative research centre (SFB) 1044.
Our Mu3e activities were funded by a DFG Emmy Noether grant until 2018.