In this talk, we will study minimal versions of Higgs inflation in the presence of a massless QCD axion. While the inflationary energy scale of the metric variant is too high to accommodate isocurvature bounds, it was argued that Palatini Higgs inflation could evade these constraints. We show, however, that an energy-dependent decay constant enhances isocurvature perturbations, implying that...
NA64 is a fixed target experiment at the CERN Super Proton Synchrotron accelerator searching for Dark Sectors employing high-energy electron, positron, hadron, and muon beams. This talk reports the latest results on sub-GeV Dark Matter searches with the 2016-2022 statistics. With the new data, NA64 is starting to probe for the first time the very interesting region of parameter space motivated...
At DESY in Hamburg, the ALPS group is developing detection systems for rare event searches based on superconducting Transition Edge Sensors (TES) together with international partners. In addition to the activities regarding an application within the ALPS II experiment, the TES platform at DESY has been adapted for direct detection of sub-MeV dark matter (DM) particles. Profiting from their low...
We explore the prospects for indirect dark-matter (DM) detection through gamma-ray emission from the annihilation of weakly interacting massive particles (WIMPs). Within the ΛCDM cosmological framework, hierarchical structure formation predicts the existence of DM halos and subhalos. If WIMPs constitute DM, they are expected to annihilate within subhalos, emitting gamma rays detectable by...
Axions and Axion-Like-Particles (ALPs) are theoretically well-motivated candidates for dark matter that, due to their large occupation number, can be described as oscillating classical fields. These particles may feature a quadratic interaction with ordinary matter which can modify the field's dynamics in the vicinity of such objects, inducing a very interesting phenomenology. In this talk, I...
In this talk I will do three things. First, I will outline the conditions under which the interaction rate of inelastic processes with a system consisting of N targets scales as N^2. Second, I will present computations of interaction rates for several weakly interacting particles, including the Cosmic Neutrino Background and Axion Dark Matter, and will explain the underlying physics. Third, I...
