Lepton collider signatures of dark CP violation


Abstract in English

We study an extension of the Standard Model (SM) in which two copies of the SM Higgs doublet are added to the scalar sector. These extra doublets do not develop a vacuum expectation value, hence, they are textit{inert}. This essentially leads to a 3-Higgs Doublet Model (3HDM) with 2 inert and 1 active scalar doublets, which we denote as I(2+1)HDM. We allow for CP-violation in the textit{inert} sector, where the lightest textit{inert} state is protected from decaying to SM particles through the conservation of a $Z_2$ symmetry, so that it is a Dark Matter (DM) candidate. For this scenario, we identify a smoking gun signature of dark CP-violation in the form of production thresholds of pairs of textit{inert} neutral Higgs bosons at an $e^+e^-$ collider.

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