A Cotangent Model for the Next-to-Minimal Orbit of E7

Let $\mathcal O_{2A_1}$ be the next-to-minimal nilpotent orbit of the complex simple Lie algebra of type $E_7$. Let $\mathfrak p_7$ be the maximal parabolic subalgebra corresponding to the simple root $α_7$, and let $\mathfrak u^+$ be its nilpotent radical. We prove that the affinization $T^*(\mathc