Heavy Higgs resonances for the neutralino relic density in the Higgs decoupling limit of the CP-noninvariant minimal supersymmetric standard model

The lightest neutralino is a compelling candidate to account for cold dark matter in the universe in supersymmetric theories with R-parity. In the CP-invariant theory, the neutralino relic density can be found in accord with recent WMAP data if neutralino annihilation in the early universe occurs via the s-channel A funnel. In contrast, in the CP-noninvariant theory two heavy neutral Higgs bosons can contribute to the Higgs funnel mechanism significantly due to a CP-violating complex mixing between two heavy states, in particular, when they are almost degenerate. With a simple analytic and numerical analysis, we demonstrate that the CP-violating Higgs mixing can modify the profile of the neutralino relic density considerably in the heavy Higgs funnel with the neutralino mass close to half of the heavy Higgs masses.