Neutralino Exchange Corrections to the Higgs Boson Mixings with Explicit   CP Violation
  A calculus for the derivatives of the eigen values of the neutralino mass matrix with respect to the CP violating background fields is developed and used to compute the mixings among the CP even and the CP odd Higgs sectors arising from the inclusion of the neutralino sector consisting of the neutralino, the Z boson, and the neutral Higgs bosons ($\chi^0_i-Z-h^0-H^0$) exchange in the loop contribution to the effective potential including the effects of large CP violating phases. Along with the stop, sbottom, stau and chargino-W-charged Higgs ($\chi^+-W-H^+$) contributions computed previously the present analysis completes the one loop corrections to the Higgs boson mass matrix in the presence of large phases. CP violation in the neutral Higgs sector is discussed in the above framework with specific focus on the mixings of the CP even and the CP odd sectors arising from the neutralino sector. It is shown that numerically the effects of the neutralino exchange contribution on the mixings of the CP even and the CP odd sectors are comparable to the effects of the stop and of the chargino exchange contributions and thus the neutralino exchange contribution must be included for a realistic analysis of mixings in the CP even and the CP odd sectors. Phenomenological implications of these results are discussed. 
Tarek Ibrahim and Pran Nath