Related papers: Cold Dark Matter from the Hidden Sector
Very weakly interacting slim particles (WISPs), such as axion-like particles (ALPs) or hidden photons (HPs), may be non-thermally produced via the misalignment mechanism in the early universe and survive as a cold dark matter population…
Axions and other very weakly interacting slim particles (WISPs) may be non-thermally produced in the early universe and survive as constituents of the dark universe. We describe their theoretical motivation and their phenomenology. A huge…
Dark matter made from non-thermally produced bosons can have very low, possibly sub-eV masses. Axions and hidden photons are prominent examples of such "dark" very weakly interacting light (slim) particles (WISPs). A suitable mechanism for…
Weakly interactive slim particles (WISPs), including the QCD axion, axion-like particles (ALPs), and hidden photons, are considered to be strong candidates for the dark matter carrier particle. The microwave cavity experiment WISPDMX is the…
Several stellar systems (white dwarfs, red giants, horizontal branch stars and possibly the neutron star in the supernova remnant Cassiopeia A) show a mild preference for a non-standard cooling mechanism when compared with theoretical…
One of the major challenges of modern physics is to decipher the nature of dark matter. Astrophysical observations provide ample evidence for the existence of an invisible and dominant mass component in the observable universe, from the…
Light cold dark matter consisting of weakly interacting slim (or sub-eV) particles (WISPs) has been in the focus of a large number of studies made over the past two decades. The QCD axion and axion-like particles with masses in the…
We review the physics case for very weakly coupled ultralight particles beyond the Standard Model, in particular for axions and axion-like particles (ALPs): (i) the axionic solution of the strong CP problem and its embedding in well…
Physics beyond the Standard Model naturally gives rise to very light and weakly interacting particles, dubbed WISPs (Weakly Interacting Slim Particles). A prime example is the axion, that has eluded experimental detection for more than…
During the last decades, experimental advances have significantly constrained the standard electroweak-scale WIMP produced via thermal freeze-out, leading to a shift away from this standard paradigm. Here we explore the possibility of an…
Increasingly stringent limits from LHC searches for new physics, coupled with lack of convincing signals of weakly interacting massive particle (WIMP) in dark matter searches, have tightly constrained many realizations of the standard…
We show that very compact axion mini-clusters can form in models where axion-like-particle (ALP) dark matter is produced via the kinetic misalignment mechanism, which is well-motivated in pre-inflationary $U(1)$ symmetry breaking scenarios.…
Non-thermalized dark matter is a cosmologically valid alternative to the paradigm of weakly interacting massive particles. For dark matter belonging to a $Z_2$-odd sector that contains in addition a thermalized mediator particle, dark…
We consider dark matter as Strongly Interacting Massive Particles (SIMPs) in a hidden sector, thermally decoupled from the Standard Model heat bath. Due to its strong interactions, the number-changing processes of the SIMP lead to its…
The cold dark matter of the Universe may be comprised of very light and very weakly interacting particles, so-called WISPs. Two prominent examples are hidden photons and axion-like particles. In this note we propose a new technique to…
While the paradigm of a weakly interacting massive particle (WIMP) has guided our search strategies for dark matter in the past decades, their null-results have stimulated growing interest in alternative explanations pointing towards…
Several ideas for new physics beyond the standard model may provide particle candidates for the dark matter in the Galactic halo. The two leading candidates are an axion and a weakly-interacting massive particle (WIMP), such as the…
We investigate the production of dark radiation (DR) from axions and axion-like particles (ALPs) as potential origins of dark matter. Focusing on the dark matter misalignment mechanism, we examine non-thermal, pre-inflationary scenarios…
Dark matter could be a thermal relic comprised of strongly interacting massive particles (SIMPs), where $3 \rightarrow 2$ interactions set the relic abundance. Such interactions generically arise in theories of chiral symmetry breaking via…
One of the most puzzling problems of modern physics is the identification of the nature a non-relativistic matter component present in the universe, contributing to more than 25$\%$ of the total energy budget, known as Dark Matter. Weakly…