Seminarium Fizyki Wielkich Energii

One of the main problem of the modern cosmology is how to explain the apparent missing energy-mass content of the Universe. The existence of dark matter particles is one of the most widely investigated possibilities to solve this issue.Among the plethora of different theoretical models that describe the coupling between normal and dark matter some of them introduce the mixing of a light dark vector boson, also called dark photon, with the SM photon.In those models, the dark photon has a non-zero mass and decays, for example, into e+e- pair.The WASA-at-COSY experiment is designed to study light meson decays such as π→e+e-γ, η→ e+e-γ (Dalitz decays) or η→e+e- with an electron-positron pair in the final state. The observation of a narrow structure in the invariant mass of e+e- spectra could be explained as the signature of the dark photon decay.We present the description of the analysis of the η→ e+e-γ channel based on 2012 data collected in WASA-at-COSY.We will also briefly review the analysis of other channels that contribute to the dark photon search in WASA-at-COSY and other experiments.