Probing New Interactions using the Mößbauer Effect

Recoilless nuclear fluorescence, the Mößbauer effect, allows for the creation and measurement of gamma-rays with extremely high quality factor (Q=3 x 10^12). As these photons are emitted and absorbed by nuclei, the effect is well shielded from many electromagnetic backgrounds. The precision of the Mößbauer effect, and its shielding from many systematic effects has allowed for the measurement of the gravitational redshift of light [Pound and Rebka 1961] and for precision tests of general relativity [Kundig 1963]. Our experiment probes small shifts of nuclear gamma-lines below the micron scale produced by couplings between nuclei and a source mass. Using the Mößbauer effect we can probe the fine- and QCD-structure constants and explore potential connections to the dark sector via the Higgs portal [Gratta et al. 2021].