Time, Place:

11:00 ,Central seminar room, library building

Speaker:

Philipp Mertsch

Title:

Galactic cosmic rays as an interstellar laboratory

Cosmic rays are a fundamental component of the Galactic ecosystem and offer insights that reach beyond the Milky Way, including how galaxies form and evolve. They also serve as probes for new physics, such as dark matter and primordial antimatter. However, all such investigations hinge on resolving the century-old question of cosmic-ray origin. Over the last decade and a half, space-based missions like AMS-02, CALET, and DAMPE have delivered a wealth of data; more recently, the ground-based LHAASO has provided high-precision measurements of protons and helium. Modeling these observations enables inferences about the classes of cosmic-ray sources and the conditions that govern their propagation -- for example, transport through turbulent magnetic fields. The emerging picture is quite intricate, suggesting that prevailing models must be revised, if not completely reworked. I will highlight recent advances in modelling Galactic cosmic rays from stochastic source populations and explore the implications for diffuse emission. A specific class of such models are motivated by evidence for inhibited diffusion around Galactic cosmic-ray sources. If time permits, I will also review recent findings on the transport of magnetic field lines and particles in synthetic turbulence.

Time, Place:

09:30 ,Central seminar room, library building

Speaker:

Dr. Marta Murillo Sanchez; Ultrafast Liquid Crystal Dynamics

Title:

High-harmonic spectroscopy in liquid crystals: Tracking the nematic–isotropic phase transition

Time, Place:

11:15 ,Central seminar room, library building

Speaker:

Dr. Alex Kavner (University of Zurich)

Title:

Super Lindhard ionization from sub-keV nuclear recoils: implications for CEvNS and dark matter searches

Germanium is an essential element for the advancement of nuclear and particle physics. High purity germanium detectors are utilized across diverse experiments including: neutrino-less double beta decay, coherent elastic neutrino nuclear scattering (CEvNS), dark matter searches, nuclear decay experiments, and many others. Full understanding of detector response to low energy nuclear recoils is of high importance being primary signature of both CEvNS and dark matter. Several recent measurements have probed the ionization produced by 254 eVnr nuclear recoils and found a significant enhancement over the theoretical prediction. These results will be discussed as well as their relevance for existing CEvNS experiments and the upcoming TESSERACT dark matter experiment.

Time, Place:

15:00 ,Central seminar room, library building

Speaker:

Prof. Agapi Emmanouilidou; University College London

Title:

Delay times and Coulomb explosion imaging in interaction of small molecules with XFEL pulses

Time, Place:

11:15 ,Central seminar room, library building

Speaker:

Till Jahnke

Title:

Molecular Ground-State Fluctuations: Subtle Feature, Large Impact

Time, Place:

11:15 ,Seminar Room 242, Bothe Lab

Speaker:

Robert Horn, MPIK

Title:

X-ray quantum optics using periodically structured cavities

Time, Place:

09:30 ,Central seminar room, library building

Speaker:

Sebastian Davidson; Highly charged ion dynamics

Title:

Resolved sideband cooling of mixed-ion Coulomb crystals

Time, Place:

11:15 ,Central seminar room, library building

Speaker:

Dr. Elisabetta Bossio (CEA Saclay, Paris-Saclay University)

Title:

Advancing Neutrino Detection with Cryogenic Calorimeters: NUCLEUS at Chooz and CRAB

Cryogenic detectors are opening new opportunities for neutrino physics and rare-event searches thanks to their exceptionally low energy thresholds. In this seminar, I will present recent progress in two complementary efforts: the NUCLEUS and CRAB experiments.The NUCLEUS experiment aims to detect O(10) eV nuclear recoils induced by coherent elastic neutrino–nucleus scattering using CaWO4 gram-scale cryogenic calorimeters. Following a successful commissioning campaign at TUM in summer 2024, the experiment is currently being installed and commissioned at the Chooz nuclear power plant in France, where it will be exposed to an intense reactor neutrino flux. I will discuss the current status of this commissioning phase, including the main challenges and first performance results, and present the expected physics reach for the upcoming data-taking phases. In parallel, the CRAB experiment uses neutron capture to study the nuclear recoil response of cryogenic detectors with high precision, a key ingredient for the interpretation of CEνNS measurements and dark-matter searches. I will present our latest results obtained with CaWO₄ and Al₂O₃ detectors. In addition to determining the nuclear energy scale with %-level accuracy in the few 100 eV energy range, I will discuss a systematic comparison with the electronic recoil response.