Conveners
Light and ultralight physics
- Giovanni Pierobon
Axions are an increasingly popular dark matter candidate with a flourishing experimental campaign now poised to discover them if they exist. However, there is a potential crisis lurking within this model which could make a discovery impossible, even if the axion does turn out to be the correct dark matter candidate. In one of the general classes of cosmological production scenarios—namely the...
As an elegant solution to the strong CP problem and promising dark matter candidate, the QCD axion is one of the best motivated particles beyond the SM. On the phenomenological side, it is extremely predictive as all its couplings to SM particles as well as its mass is determined by a single scale, the axion decay constant. The hunt for the QCD axion, both with terrestrial experiments as well...
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. At low energies, canonical QCD axions have a model-independent quadratic interaction with nucleons that can be extended to gluon-coupled ALPs. Nucleon densities modify the axion’s and ALP’s field...
Dark matter with mass in the crossover range between wave dark matter and particle dark matter, around $(10^{-3}, 10^3)$ eV, remains relatively unexplored by terrestrial experiments. In this mass regime, dark matter scatters coherently with macroscopic objects. The effect of the coherent scattering greatly enhances the accelerations of the targets that the dark matter collisions cause by a...
We explore the $511$~keV emission associated to sub-GeV dark matter (DM) particles that can produce electron-positron pairs and form positronium after thermalizing. We use $\sim16$~yr of SPI data from INTEGRAL to constrain DM properties, including the full positron propagation and losses, and the free electron density suppression away from the Galactic plane. We show that the predicted...
