Analysis of the Neutralino System in Two--Body Decays of Neutralinos

Abstract

In the minimal supersymmetric standard model (MSSM), the neutralinos, the spin--1/2 Majorana superpartners of the neutral gauge and Higgs bosons, are expected to be among the light supersymmetric particles that can be produced copiously at future high--energy colliders. We analyze two--body neutralino decays into a neutralino plus a $Z$ boson or a lightest neutral Higgs boson $h$, allowing the relevant parameters to have complex phases. We show that the two--body tree--level decays of neutralinos are kinematically allowed in a large region of the MSSM parameter space and they can provide us with a powerful probe of the Majorana nature and CP properties of the neutralinos through the $Z$--boson polarization measured from $Z$--boson leptonic decays.