Torsten Bringmann
First-order phase transitions in a dark sector have been invoked as an intriguing possibility to explain the observed stochastic gravitational wave background at nanohertz frequencies. Here we perform a comprehensive study of the generic…
Dark matter is a fundamental constituent of the universe, which is needed to explain a wide variety of astrophysical and cosmological observations. Although the existence of dark matter was first postulated nearly a century ago and its…
Strong first-order phase transitions in a dark sector offer a compelling explanation for the stochastic gravitational wave background in the nano-Hertz range recently detected by pulsar timing arrays (PTAs). We explore the possibility that…
The primordial power spectrum of matter density perturbations contains highly valuable information about new fundamental physics, in particular cosmological inflation, but is only very weakly constrained observationally for small…
The standard model of cosmology has provided a good phenomenological description of a wide range of observations both at astrophysical and cosmological scales for several decades. This concordance model is constructed by a universal…
Sub-GeV dark matter (DM) particles produced via thermal freeze-out evade many of the strong constraints on heavier DM candidates but at the same time face a multitude of new constraints from laboratory experiments, astrophysical…
The thermal freeze-out mechanism in its classical form is tightly connected to physics beyond the Standard Model around the electroweak scale, which has been the target of enormous experimental efforts. In this work we study a dark matter…
High-frequency gravitational waves can be detected by observing the frequency modulation they impart on photons. We discuss fundamental limitations to this method related to the fact that it is impossible to construct a perfectly rigid…
Gravitational waves from a first-order cosmological phase transition, at temperatures at the MeV-scale, would arguably be the most exciting explanation of the common red spectrum reported by the NANOGrav collaboration, not the least because…
We propose a novel mechanism to generate sterile neutrinos $\nu_s$ in the early Universe, by converting ordinary neutrinos $\nu_\alpha$ in scattering processes $\nu_s\nu_\alpha\to\nu_s\nu_s$. After initial production by oscillations, this…
The irreducible upscattering of cold dark matter by cosmic rays opens up the intriguing possibility of detecting even light dark matter in conventional direct detection experiments or underground neutrino detectors. The mechanism also…
Cosmological and astrophysical observations currently provide the only robust, positive evidence for dark matter. Cosmic probes of dark matter, which seek to determine the fundamental properties of dark matter through observations of the…
This report summarizes the findings of the CF1 Topical Subgroup to Snowmass 2021, which was focused on particle dark matter. One of the most important scientific goals of the next decade is to reveal the nature of dark matter (DM). To…
We assess the status of a wide class of WIMP dark matter (DM) models in light of the latest experimental results using the global fitting framework $\textsf{GAMBIT}$. We perform a global analysis of effective field theory (EFT) operators…
Physical theories that depend on many parameters or are tested against data from many different experiments pose unique challenges to statistical inference. Many models in particle physics, astrophysics and cosmology fall into one or both…
DarkSUSY is a versatile tool for precision calculations of a large variety of dark matter-related signals, ranging from predictions for the dark matter relic density to dark matter self-interactions and rates relevant for direct and…
Relic density calculations of dark matter freezing out from the primordial plasma have reached a high level of sophistication, with several numerical tools readily available that match the observationally required accuracy. Dark matter…
We propose a novel mechanism for the production of dark matter (DM) from a thermal bath, based on the idea that DM particles $\chi$ can transform heat bath particles $\psi$: $\chi \psi \rightarrow \chi \chi$. For a small initial abundance…
We introduce DRAKE, a numerical precision tool for predicting the dark matter relic abundance also in situations where the standard assumption of kinetic equilibrium during the freeze-out process may not be satisfied. DRAKE comes with a set…
We determine the upper limit on the mass of the lightest neutrino from the most robust recent cosmological and terrestrial data. Marginalizing over possible effective relativistic degrees of freedom at early times ($N_\mathrm{eff}$) and…