Within the framework of three lepton families we have derived an exact and compact formula to describe the matter effect on neutrino mixing and CP violation. This model- and parametrization-independent result can be particularly useful for recasting the fu

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ahep-ph/0002246LMU-00-02NewFormulationofMatterE ectsonNeutrinoMixingandCPViolationZhi-zhongXing SektionPhysik,Universit¨atM¨unchen,Theresienstrasse37A,80333Munich,GermanyAbstractWithintheframeworkofthreeleptonfamilieswehavederivedanexactandcompactformulatodescribethemattere ectonneutrinomixingandCPviolation.Thismodel-andparametrization-independentresultcanbeparticularlyusefulforrecastingthefundamentallepton avormixingmatrixfromavarietyoflong-baselineneutrinoexperiments.