2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/227844We consider the contributions to $g_μ-2$ from fourth generation heavy neutral and charged leptons, $N$ and $E$, at the one-loop level. Diagrammatically, there are two types of contributions: boson-boson-$N$, and $E$-$E$-boson in the loop diagram. In general, the effect from $N$ is suppressed by off-diagonal lepton mixing matrix elements. For $E$, we consider flavor changing neutral couplings arising from various New Physics models, which are stringently constrained by $μ\to eγ$. We assess how the existence of a fourth generation would affect these New Physics models.Minor changes, with references updatedHigh Energy Physics - Phenomenologytext