Dark Matter in the CP-violating NMSSM

In the Next-to-Minimal Supersymmetric Standard Model there is a strong correlation between the mass terms corresponding to the singlet Higgs and the singlino interaction states, both of which are proportional to the parameter $\kappa$. If this parameter is complex, explicit CP-violation occurs in the Higgs as well as the neutralino sectors of the model at the tree level, unlike in the minimal scenario. A small magnitude of $\kappa$ typically yields a $\cal{O}$(10) GeV lightest neutralino with a dominant singlino component. In such a scenario, the phase of $\kappa$, beside modifying the properties of the five Higgs bosons, can also have a crucial impact on the phenomenology of the neutralino dark matter. In this study we perform a first investigation of this impact on the relic abundance of the dark matter solutions with sub-100 GeV masses, obtained for parameter space configurations of the model that are consistent with a variety of current experimental data.Comment: 26 pages, 5 figures, 2 tables. Some references added. PandaX-4T (2021) limits included; results unchanged. Version published in EPJ