  We show the first results of a new cavity based haloscope searching for dark
photons with masses around $34~\mu\text{eV}$. Dark photons are hypothetical
vector particles and a compelling dark matter candidate. Having the same
quantum numbers as photons a kinematic mixing between both is expected, leading
to conversions from dark photons to standard model photons, where the photon
frequency depends on the dark photon mass. For wavelengths in the microwave
regime resonators are typically used to enhance the signal. A new experiment is
setup at the University of Mainz. In this paper we present the initial results
from the new setup searching for dark photons utilising a 8.3 GHz copper cavity
at LHe temperatures. Limits on the kinetic mixing parameter $\chi < (6.20 \pm
3.15^\text{(exp.)} \pm 9.65^\text{(SG)}) \cdot 10^{-14}$ at 95\% CL are set at
a single frequency as proof of concept. Finally the next steps of the
experiment and expected sensitivity are detailed.

High Energy Physics - Experiment;Cosmology and Nongalactic Astrophysics;High Energy Physics - Phenomenology