Speaker
Description
Within the many different possible extensions of the Standard Model (SM) to describe dark matter, the addition of an extra U(1) gauge boson called dark photon is a particularly attractive possibility because of it predictivity and simplicity. These particles interact with the SM solely through kinetic mixing with standard photons and can acquire mass via the Stückelberg mechanism. For sub-keV masses, the absorption of dark photons is a possible detection channel.
Our research aims to identify the optimal detector material to maximize the detection probability, and consists of two steps. First, we determine a material-independent upper limit on the absorption rate of solar dark photons by combining methods from particle, astro- and solid state physics. In a second step, we compare theoretical absorption rates of various materials against this limit to identify materials that come closest to the ideal detection rate. This procedure works independently of the coupling strength between dark photons and the SM.
To calculate the theoretical upper limit, the absorption rate has to be decomposed into the transverse and longitudinal contributions, which can be related to the material’s dielectric function. For the longitudinal component, we use Kramers-Kronig relations to
derive the desired upper limit. We are currently investigating a similar approach for the transverse part. The combined results will guide the selection of materials for detecting dark photons, potentially advancing detection capabilities.
