Organisation: JGU > Faculty 08 > Institute of Physics > Group Experimental Particle & Astroparticle Physics (ETAP) > JUNO
Research: JGU > Faculty 08 > Physics > Astroparticle & Neutrino Physics > JUNO

The Jiangmen Underground Neutrino Observatory (JUNO), located in southern China, is the world’s largest liquid-scintillator neutrino detector, which began operation in August 2025. It uses antineutrinos emitted by nuclear power plants to study neutrino oscillations with unprecedented precision. With its 20-kiloton target mass and exceptional performance, JUNO also serves as a powerful astroparticle observatory, studying neutrinos from distant astrophysical sources and searching for rare processes that could reveal physics beyond the Standard Model.

The discovery of neutrino oscillations, whereby neutrinos change from one flavour to another, demonstrated that neutrinos have non-zero masses. However, their absolute mass scale and mass ordering remain unknown.

The main goal of JUNO is to determine the neutrino mass ordering—whether the third neutrino mass eigenstate, m3, is heavier or lighter than the other two. JUNO searches for subtle signatures of the mass ordering in the energy spectrum of antineutrinos emitted by two nuclear power plants at an average distance of 52.5 km. Its exceptional energy resolution and large mass are crucial for resolving these features.

Since the beginning of data taking in August 2025, JUNO has achieved world-leading measurements of the solar neutrino oscillation parameters. Combining its updated preliminary measurement with external constraints from the Daya Bay experiment and long-baseline accelerator-neutrino experiments, JUNO has also obtained its first result on the neutrino mass ordering, favouring normal ordering (m1<m2<m3).

JUNOs physics potential also encompasses neutrinos from many other sources. Of particular importance are geoneutrinos, which originate from radioactive decays inside the Earth and are measured using the same inverse-beta-decay data set as reactor antineutrinos. JUNO presented its first geoneutrino result at the Neutrino 2026 conference.

JUNO also strives towards the detection of the Diffuse Supernova Neutrino Background (DSNB), which consists of the neutrinos emited by all past supernova explosions in the Universe. So far neutrino experiments have not been able to discover the DSNB due to its extremely faint signal. However, discovery may be right around the corner, as Super-Kamiokande reported first hints of a signal at the recent Neutrino26 conference.

In addition, JUNO studies neutrinos from the Sun, the atmosphere, and transient astrophysical sources as supernovae, providing information about neutrino properties and the physical processes occurring in these sources.

  • Precision Neutrino Oscillations: High-precision measurements of reactor neutrinos to determine the neutrino mass ordering and test the three-flavour oscillation framework.
  • Astrophysical Neutrinos: Searches for rare signals such as the Diffuse Supernova Neutrino Background and neutrinos from stellar explosions.
  • Neutrinos from Natural Sources: Studies of geo- and solar neutrinos to probe the Earth and Sun.
  • Detector Technology: Development of ultra-low-background liquid-scintillator detectors, calibration systems, and analysis techniques.

The group works across the full JUNO analysis chain, from detector calibration and background modelling to precision measurements of reactor neutrino oscillations. Research also includes geo- and solar neutrinos.

The Neutrino Group of Prof. Dr. Dr. Livia Ludhova was established in November 2015 through funding she secured from the Helmholtz Association’s recruitment initiative. This programme remains the group’s principal source of funding, complemented by support from the German Research Foundation (DFG) and the PRISMA ++ Cluster of Excellence. The group has since grown significantly and now typically comprises around ten members.   

On 15 September 2024, the group was transferred from Forschungszentrum Jülich to the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, while Prof. Dr. Dr. Livia Ludhova’s professorship moved from RWTH Aachen University to Johannes Gutenberg University Mainz. The group physically relocated to Mainz in April 2025 and is now based there.  

The group is fully dedicated to the JUNO experiment, with its members contributing across the entire analysis chain—from detector simulation, calibration, data quality and detector monitoring to event reconstruction, event selection and high-level physics analysis. Its current research focuses primarily on oscillation studies using reactor antineutrinos and on geoneutrinos. The group is also preparing to expand its activities to solar neutrinos and the Diffuse Supernova Neutrino Background (DSNB).

For more information about Prof. Ludhova’s Neutrino Group, please visit the group’s website.

The group develops detector technologies for rare neutrino signals and leads efforts toward detecting the Diffuse Supernova Neutrino Background. It also contributes to the analysis of the background formed by cosmogenic isotopes.

  • The research group of Prof. Michael Wurm was founded in 2014 and currently consists of around 15-20 people including postdoctoral fellows, PhD, master and bachelor students.
  • It investigates astrophysical neutrinos and develops detector technologies for rare-event neutrino experiments. Our work combines neutrino data analysis with detector development within the JUNO collaboration.
  • A central focus is the search for the yet undiscovered Diffuse Supernova Neutrino Background (DSNB) with JUNO.
  • Prof. Wurm is L2 manager for liquid scintillator/OSIRIS for the JUNO experiment with his group being responsible for the pre-detector OSIRIS that ensured the radiopurity of the liquid scintillator for JUNO, crucial to detection of rare neutrino events.
  • The group is working on R&D projects like the MANGO setup for invetsigation of liquid scintillator properties and the development of a Cherenkov calibration source for JUNO.
  • It also participates in the neutrino oscillation analysis by investigating cosmogenic isotopes which induce backgrounds but can also be used to calibrate the detector.
  • AURORA, a laser calibration system for JUNO, has also been developed by the group.
  • The group is also part of other collaborations like ANNIE and works on R&D projects all around liquid scintillator and neutrino experiments.