Searches for Dark Matter and Axion-Like Particles at Belle II

Helmholtz Young Investigator Group of Torben Ferber

Research Activities

Fig.: Dark Photon production and decay into (invisible) Dark Matter at Belle II (MC simulation).

The Young Investigators Group is situated at DESY. It is part of the existing DESY Belle II group and is linked to the University of Hamburg. We participate in the Belle II experiment being run at the SuperKEKB collider at KEK in Tsukuba, Japan.

We focus on Dark Matter searches at the intensity frontier. This includes searches for Dark Photons decaying into light Dark Matter and Axion-Like Particles (ALPs) at Belle II. These searches are competitive even with small datasets that can be acquired in several months of data taking at Belle II.

Our activities are closely related to the reconstruction of photons in the electromagnetic calorimeter (ECL) of Belle II. We are leading the development of ECL reconstruction software with a strong focus on Machine Learning to improve calibration, photon detection and reconstruction. Members of the YIG are convenors of the Belle II Analysis Software, Belle II Event Generators Software, Belle II ECL software, Belle II Dark Sector Physics, and Belle II Neutrals Physics working groups.

We collaborate with the DESY Theory group and explore new directions of Dark Matter searches at the intensity frontier with neutral and displaced signatures.


Torben Ferber (group leader,
Homepage:, Short biography

Nataliia Kovalchuk (postdoc,
Sam Cunliffe (postdoc,
Yu Hu (postdoc,
Michael De Nuccio (PhD student,


"Search for Dark Matter and ALPs at Belle II" (Sam Cunliffe)
( Flavour and Dark Matter 2018 , KIT (Karlsruhe), 24-26.09.2018)

"Axion/Dark photon: Collider" (Torben Ferber)
(The Puzzle of Dark Matter Symposium, DESY, 30.10.2018)

"Belle II: Lessons learned from Phase 2" (Torben Ferber)
(Belle II Physics Week, KEK, 22-26.10.2018)

"Flavour Physics" (Sam Cunliffe)
(Summer Student Lectures, DESY, 24.08.2018)

"Search for Dark Matter at Belle II" (Torben Ferber) (slides)
(Physikalisches Kolloquium, Karlsruhe, 11.05.2018)

"Searches for Dark Matter and Axion-Like Particles at Belle II" (Torben Ferber) (slides)
(SFB 676 Colloquium, Hamburg, 25.04.2018)

"Search for Dark Matter at Belle II" (Torben Ferber) (slides)
(Particle Physics Seminar, Mainz, 23.04.2018)

"Probing dark photons and ALPs at B-factories" (Torben Ferber)
(DM@LHC, Heidelberg, 03.-06.04.2018)

"Searches for Dark Matter at Belle II" (Torben Ferber) (slides)
(DPG, Wuerzburg, 19.-23.03.2018)


Opportunities for students
We are looking for undergraduate (bachelor, master/diploma) and graduate (Ph.D.) students who would like to become a part of our growing group. If you are interested please contact Dr. Torben Ferber.

Available master theses (in German):
"Softwareentwicklung fuer Belle II"
"Suche nach Dunkler Materie bei Belle II"

Opportunities for postdoctoral fellows
We encourage interested physicists who have completed their Ph.D. within the last 4 years, to apply for DESY fellowships in experimental particle physics. Please contact Dr.
Torben Ferber
for additional information.