Speaker
Description
The dark photon is the gauge boson of a hypothetical dark sector, representing a minimal extension to the Standard Model. This massive particle interacts with the visible photon through kinetic mixing and has been widely studied as a dark matter candidate. We consider a scenario in which an initially unpopulated dark sector is populated via photon–dark photon conversion prior to recombination, during the $\mu$ and early $y$ distortion epochs. The associated energy transfer and change in photon number produce potentially observable distortions in the CMB spectrum. The monopole signal has previously been computed and compared with COBE/FIRAS data to constrain model parameters. Here, we extend this framework to the anisotropic case, including perturbations and higher multipoles, using the recently developed Frequency Hierarchy system. The resulting power spectra can be directly compared with data from the Atacama Cosmology Telescope and Planck, enabling observational constraints on dark photon parameters from spectral distortions for the first time, as I explain in this talk.
| Other topic / keywords: | CMB spectral distortions |
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