A study of the impact of stau mixing on the chargino and neutralino limits

Mixing effects in the third generation may affect the limits on the mass of the lightest neutralino extracted in the MSSM using LEP data. In the present paper the impact of stau mixing on the neutralino limit is studied for the full parameter range, parametrized by the stau mixing angle $\phitau$. The data used in the analysis have been collected by the ALEPH experiment at LEP at various center-of-mass energies in the range between 189 and 208 GeV. Special emphasis is given to a discussion of mixing effects in the deep gaugino region, where the LEP mass limit of the lightest neutralino is set.