In light of recent DAMIC-M results, we present the status of thermal-relic dark matter $\chi$ coupled to a kinetically mixed dark photon $A^{\prime }$. In the predictive “direct annihilation” regime, $m_{A^{\prime }}>m_{\chi }$, the relic abundance depends on the kinetic mixing parameter, and there is a minimum value compatible with thermal freeze-out. Using only electron- and nuclear-recoil direct-detection results, we find that, for complex scalar dark matter, the direct annihilation regime is now excluded for nearly all values of $m_{\chi }$; the only exception is the resonant annihilation regime where $m_{A^{\prime }}\approx 2m_{\chi }$. Direct annihilation relic targets for other representative models, including Majorana and pseudo-Dirac candidates, remain viable across a wide range of model parameters but will be tested with a combination of dedicated accelerator searches in the near future. In the opposite “secluded annihilation” regime, where $m_{\chi }>m_{A^{\prime }}$, this scenario is excluded by cosmic microwave background measurements for all $m_{\chi }\lesssim 30\mathrm{GeV}$. Similar conclusions in both the direct and secluded regimes hold for all anomaly-free vector mediators that couple to the first generation of electrically charged Standard Model particles.

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• Dark matter
• Hypothetical gauge bosons