Organisation: Johannes Gutenberg University > Faculty 08 > Institute of Physics > Experimental Particle & Astroparticle Physics (ETAP) > AG Böser
Research: J ohannes Gutenberg University > Faculty 08 > Physics > Astro-, Astroparticle & Neutrino Physics > AG Böser

Our research and teaching center on astroparticle and low-energy neutrino physics, focusing on the properties of neutrinos and their role in the universe. Neutrinos offer insights into some of the most profound questions in physics and cosmology, such as the origin of mass, the matter-antimatter imbalance, the engines behind cosmic phenomena like supernovae, and possible physics beyond the Standard Model.

With the IceCube Neutrino Observatory we focus on precision measurements of neutrino oscillations as well as neutrino astronomy and the experimental search for supernova neutrinos. In addition, we contribute to the development of photosensor technologies essential for next-generation neutrino detectors. Our concept, which is based on wavelength-shifting and light-conducting materials, promises a significant increase in detection efficiency and, in particular, a significant reduction in noise.

The same technology can also be applied to readout scintillation light in the NuDoubt⁺⁺ experiment to improve the light collection and thus energy resolution -- an important feature of any neutrino-less double beta experiment. Advancing the reconstruction and background rejection will allow to measure double-positron decays at an unprecedented precision and help answering the question wether neutrinos are of Majorana type.

Project 8 aims to measure the absolute values of the neutrino masses in tritium beta decay. Using the novel CRES technology enables unprecedented energy resolution -- if combined with a source of atomic tritium. This requires to dissociate tritium molecules at temperatures beyond 2000K, before they are cooled to be trapped at millikelvin temperatures. A non-trivial task as the atoms readily recombine into molecules on any physical surface and therefore must be trapped by magnetic fields.

IceCube, located at the South Pole, is the world's largest neutrino detector and plays a central role in exploring the high-energy neutrinos from the universe as well as fundamental neutrino properties. It enables the detection of neutrinos from astrophysical sources as well as those produced in Earth’s atmosphere.

Our group is engaged in both the analysis of neutrino data and the development of experimental hardware, with the goal of advancing the scientific reach of the IceCube Neutrino Observatory and its planned upgrades.

On the analysis side, we focus on atmospheric neutrino oscillations. These measurements are sensitive to the neutrino mass ordering—one of the remaining unknowns in the Standard Model—and also offer a unique window into potential non-standard neutrino interactions, which could signal new physics.

In parallel, we contribute to the design and development of next-generation detector technologies, particularly in the area of low-noise, high-efficiency photosensors. Our group contributes to the design and implementation of Wavelength-shifting Optical Modules (WOMs)—a novel class of photosensors that combine wavelength-shifting materials and light-guiding geometries. WOMs offer significantly improved light collection efficiency and drastically reduced noise rates, making them ideal for low-energy neutrino detection.

Within the group, we are also developing the Neutron Echo technique to improve event classification of high-energy events, which will provide a deeper understanding of the production mechanisms in astrophysical sources. This novel approach has the potential to enhance flavor discrimination between electron and tau neutrino showers beyond what is achievable using shower topology alone.

There have been significant gains in characterizing neutrino properties in recent years, however the absolute neutrino mass scale continues to be elusive. The Project 8 collaboration seeks to probe this quantity directly via kinematic analysis of tritium beta decay, using the cyclotron radiation emission spectroscopy (CRES) technique. In order to make neutrino mass measurements with a design sensitivity of 40meV, the Project 8 experiment must use atomic tritium. Our working group together with AG Fertl are performing critical R&D for atomic tritium production. In the lab, a Mainz Atomic Test Stand dissociates hydrogen (a safe substitute for tritium) at temperatures in excess of 2000K, while diagnostic tools (calorimetry and spectrometry) are being developed to characterize the atomic beam. Future versions of the test stand will include a beam-cooling element, prototyping of which is underway.

The NuDoubt⁺⁺ experiment is focused on detecting the rare nuclear process of double beta plus decay, which involves the emission of two positrons. Measuring this decay is challenging due to its low probability, difficult-to-detect signatures, and the scarcity of suitable candidate nuclei. To address these challenges, we have developed an innovative detector concept that combines hybrid and opaque scintillation detector technologies with new light read-out techniques using novel wavelength shifting fibers. This combination is particularly effective for identifying positrons, for which we are developing novel background rejection techniques.

We anticipate that with just one tonne-week of exposure, our detector will be capable of discovering two-neutrino double beta plus decay modes. Furthermore, it has the potential to significantly improve the detection limits for neutrinoless double beta plus decays compared to current experiments.

Authors: Project 8 Collaboration

2025

Authors: Manuel Böhles, Sebastian Böser, Magdalena Eisenhuth, Cloé Girard-Carillo, Kitzia M. Hernandez Curiel, Bastian Keßler, Kyra Mossel, Veronika Palušová, Stefan Schoppmann, Alfons Weber, Michael Wurm

2024

Authors: Philipp Eller, Aaron T. Fienberg, Jan Weldert, Garrett Wendel, Sebastian Böser, D.F. Cowen

2023

Authors: Benjamin Bastian-Querner, Lucas Binn, Sebastian Böser, Jannes Brostean-Kaiser, Dustin Hebecker, Klaus Helbing, Timo Karg, Lutz Köpke, Marek Kowalski, Peter Peiffer, Anna Pollmann, John Rack-Helleis, Martin Rongen, Lea Schlickmann, Florian Thomas, Anna Vocke

2022

Authors: IceCube Collaboration

2021

Authors: JUNO Collaboration Members, IceCube Gen2 Collaboration

2020

Authors: Sebastian Böser, Christian Buck, Carlo Giunti, Julien Lesgourgues, Livia Ludhova, Susanne Mertens, Anne Schukraft, Michael Wurm

2020

Authors: IceCube Collaboration

2020

Authors: Project 8 Collaboration

2017

Authors: Sebastian Böser, Marek Kowalski, Lukas Schulte, Nora Linn Strotjohann, Markus Voge

2015

Authors: IceCube Collaboration

2011

Authors: IceCube Collaboration

2010

Aktuelle Themen aus der Teilchen- und Astroteilchenphysik
Dozent:in: Univ.-Prof. Dr. Sebastian Böser; Univ.-Prof. Dr. Volker Büscher; apl. Prof. Dr. Frank Fiedler; Univ.-Prof. Dr. Lucia Masetti; Univ.-Prof. Dr. Uwe Gerd Oberlack; Dr. Christian Schmitt; Dr. Ulrich Schäfer; Dr. Duc Bao Ta; Univ.-Prof. Dr. Stefan Tapprogge; Dr. Rainer Wanke; Univ.-Prof. Dr. Michael Wurm
Arbeitsgruppenseminar Detektorentwicklung seltene Zerfälle
Dozent:in: Univ.-Prof. Dr. Sebastian Böser; Stefan Schoppmann; Prof. Dr. Alfons Weber; Univ.-Prof. Dr. Michael Wurm
Arbeitsgruppenseminar über das IceCube Neutrinoteleskop am Südpol
Dozent:in: Univ.-Prof. Dr. Sebastian Böser
Arbeitsgruppenseminar zur Neutrinomassenmessung
Dozent:in: Univ.-Prof. Dr. Sebastian Böser; Univ.-Prof. Dr. Martin Fertl
Hochempfindliche Optische Sensoren für die Neutrinophysik
Dozent:in: Univ.-Prof. Dr. Sebastian Böser
Vertiefende Kapitel der Astroteilchen- und Astrophysik
Dozent:in: Univ.-Prof. Dr. Sebastian Böser; Savitri Gallego

WiSe 2025/26

PhD and postdoctoral positions are regularly available in the listed research areas, subject to funding availability. For inquiries regarding open research positions please consult MPA PhD fellowship or IPH career opportunities webpages. In case of questions contact us at sboeser@uni-mainz.de.

We offer a wide range of thesis topics for students interested in astroparticle and neutrino physics that provide opportunities to contribute to internationally recognized projects such as IceCube, Project 8, and NuDoubt⁺⁺. Whether you're drawn to hands-on work in the lab or data analysis and simulation, we will find a topic that matches your interests.

If you're curious to see how we work at the intersection of fundamental physics and advanced technology, please contact sboeser@uni-mainz.de to learn more and discuss available topics.

We welcome students who are interested in internships within our group, with stays ranging from a few weeks to several months. Financial support is available, for example, through the PRISMA⁺⁺ internship program.

We maintain a list of past Bachelor's, Master's, and doctoral theses completed within our group:

Arbeitsgruppenseminar Detektorentwicklung seltene Zerfälle