Long-lived particle phenomenology in the 2HDM+a model

Higgs decays displaced from the primary interaction vertex represent a striking experimental signature that is actively searched for by ATLAS, CMS and LHCb collaborations. We point out signals of this type appear in context 2HDM+$a$ model if mixing angle $\theta$ two CP-odd weak spin-0 eigenstates tiny dark matter (DM) sector either decoupled or kinematically inaccessible. Utilising suitable benchmark scenarios, we determine constraints on parameter space are set existing LHC searches long-lived particles (LLPs) decays. find depending precise mass spectrum states, angles ballpark few $10^{-8}$ to $10^{-5}$ can be excluded based Run II data. This finding emphasises unique role signatures play constraining model. The ensuing DM phenomenology also discussed. In particular, show choices leading an interesting LLP simultaneously explain abundance observed today's Universe.