Search for Massive Dark Photons with the CMS Experiment

Various Beyond Standard Model (BSM) hypotheses suggest new particles manifesting as GeV scale resonances in collider experiments such as the Large Hadron Collider (LHC). New particle candidates include massive dark photons. We present the preliminary results of a search for prompt dimuon resonances using fully reconstructed data collected in 2022 and 2023 at the Compact Muon Solenoid (CMS), with focus on dark photon candidates. The search exploits a new low-mass dimuon trigger part of the B-parking program, and probes masses of 2-8 GeV. Improvements from previous searches include the development of dedicated MVA selection strategies that leverage the full reconstructed event information from the new trigger.