Analysis Tools for the Dark Matter Interpretation of Recent Experiments and Cosmological Observations (ADMIRE & CO)

• Applicant: Professor Dr. Felix Kahlhoefer
• Subject Area: Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields ; Astrophysics and Astronomy
• Term: from 2017 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 359879810

The overwhelming evidence that visible matter constitutes only a small fraction of the universe is at the same time humbling and exciting. The nature of the dominant form of matter, called dark matter, is still unknown, but thanks to huge improvements in experimental sensitivity, the coming years offer many opportunities for discovering dark matter particles and determining their fundamental properties. At the same time, the fact that no conclusive dark matter signal has yet been observed implies that we need to re-examine the assumptions made about dark matter and broaden our search programme.This proposal aims to extend the range of analysis tools available to probe dark matter and use them to explore new classes of dark matter models, in which the dark matter particles have much smaller masses or couplings than commonly assumed. Such dark matter particles are challenging to detect in the laboratory, but they predict a range of interesting effects in early universe cosmology. The proposed analysis tools will enable a detailed interpretation of cosmological data in the context of dark matter models and thereby build a bridge between the fields of cosmology and particle physics.This objective can be divided into three tasks. The first is to develop a framework for translating the fundamental parameters of dark matter models to an effective description suitable for calculating cosmological observables. The second is to publish a code to calculate constraints on the energy injection from annihilations or decays of dark matter particles across the entire cosmological history. The third task is to explore how the high temperatures in the early universe give rise to unique effects such as phase transitions and gravitational waves connected to dark matter. Once these tasks have been completed, the final goal will be to carry out global analyses of non-standard dark matter models by bringing together all available information from laboratory experiments and cosmology.Funding is requested for the salary and travel expenses of the Junior Research Group leader and of a postdoctoral research assistant focusing on the topic of phase transitions and gravitational waves. This project will be carried out in close collaboration with particle physicists and cosmologists in order to maximize the impact on both communities. Moreover, all developed code will be made publicly available in order to enable others to perform similar analyses and prepare for exciting dark matter signals in the near future. By exploring wide ranges of dark matter models with complementary information from different branches of physics, we have a unique chance to solve one of the great puzzles of the universe.

• DFG Programme: Independent Junior Research Groups