2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/41423The goal of this article is to outline the advantages of the measurement of left-right asymmetries in lepton-lepton ($l^{-}l^{-}\to l^{-}l^{-}$) scattering for performing precision measurements of $\sin^2 θ_W$ and the discovery of ``new physics''.RevTeX, 6 pages and one .eps figure. Based on contribution to XXII Encontro Nacional de Fisica de Particulas e Campos, October 22--26, Sao Lourenco (MG), Brazil. One typo corrected and a new reference includedHigh Energy Physics - PhenomenologyHigh Energy Physics - Experimenttext