Mu3e Experiment

Search for the forbidden decay
\mu^+ \to e^+ e^+ e^-

The Mu3e experiment is a new search for the lepton-flavour violating decay of a positive muon into two positrons and one electron.

Current news

27. October 2017


Dorothea vom Bruch successfully defends her Ph.D. thesis on the Mu3e filter farm and MuPix timing behaviour

Dorothea vom Bruch 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.

3. October 2017


First MuPix8 beam test at DESY

We are testing our new large sensor chip, the MuPix8, in the electron beam at DESY, Hamburg. One of the high resolution EUDET telescopes serves as a reference for efficiency and resolution measurements. Have a look at the picture gallery.

27. September 2017


Collaboration meeting in Mainz and new collaborators

In a two day meeting in Mainz we had the pleasure of welcoming four new institutes, namely the universities of Liverpool, Oxford and Bristol as well as University College London to the collaboration. We also discussed progress on all subdetectors and a variety of integration issues.

1. September 2017


MuPix8, our first large sensor, has arrived

We have just received first samples of the MuPix8 chip from the foundry. This is our first large (20mm x 10mm) pixel sensor prototype and a big step on the way to building the Mu3e tracking detector. The prototype will now be thoroughly tested in the labs in Karlsruhe and Heidelberg and will also soon see first beam at DESY in Hamburg, PSI and MAMI in Mainz.

13. February 2017


Meeting on future directions with Mu3e in Wengen

We spent four days in Wengen, Switzerland, discussing ideas for physics with the Mu3e apparatus beyond the search for the lepton-flavour violating decay of the muon to three electrons. Collaboration members and theorists presented new ideas for future measurements with the high acceptance, high resolution Mu3e spectrometer using high intensity muon and pion beams at PSI. Technical challenges and promising R&D directions related to high-intensity data taking were also discussed in detail. Picture gallery.

6. February 2017

Mu3e review at the PSI user meeting

In the context of the annual PSI user meeting, the Mu3e experiment underwent a detailed review by the research committee for particle physics at the ring cyclotron, discussing the preliminary version of the phase I Mu3e technical design report.

3. November 2016


Roman Gredig successfully defends Ph.D. thesis on the fibre tracker for Mu3e

Roman Gredig was the first Ph.D. student working on the Mu3e fibre tracker. He has now successfully defended his thesis at the University of Zürich. The thesis is available here.

10. October 2016

Mu3e contributions to PIXEL2016

The Mu3e collaboration has presented the latest state of the pixel detector development at the PIXEL2016 conference. The proceedings on the sensor and the mechanics and cooling are now available on the arXiv. You can also find the presentation slides on the talks page.

1. July 2016


Test beams at PSI and MAMI

We spent a week testing our MuPix prototypes and scintillating fibres at PSI with a mixed pion, muon and electron beam. This was followed by a beam time with the high intensity electron beam at MAMI in Mainz. The data obtained will help us to further optimise the sensor performance and check the correct working of the readout architecture even at rates beyond what is expected in the Mu3e experiment. Pictures can be found in the PSI gallery and the MAMI gallery.

15. June 2016

A New Three-Dimensional Track Fit with Multiple Scattering

The paper describing the track fit especially developed for the Mu3e experiment is available on the arxiv. Taking the multiple Coulomb scattering in the detector material as the dominant uncertainty, we were able do develop a a very fast and robust track fitting algorithm, that now lies at the heart of the Mu3e track reconstruction.

30. March 2016

The MuPix System-on-Chip for the Mu3e Experiment

Our paper describing the latest version of our high-voltage monolithic active pixel sensor, the MuPix7, has just appeared on the arxiv. It describes the inner workings of the chip as well as the results of a very intense campaign of beam tests at PSI, DESY in Hamburg, CERN in Geneva and MAMI in Mainz.

3. February 2016


Moritz Kiehn successfully defends Ph.D. thesis on tracking algorithms for Mu3e

Tests of MuPix chips with electron beams as well as tracking algorithms suited for the multiple scattering dominated environment at Mu3e were the topics of Moritz Kiehn's thesis. He successfully defended the thesis at Heidelberg University. The thesis will be available here soon.
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