2026/07/24 by Ricardo Monteiro, Lecheng Ren, Daniel Siretanu
#hep-th #gr-qc
We revisit Kerr-NUT metrics and related spin-s fields in D≥4, and study their associated scattering amplitudes. Starting in position space, we highlight the interpretation of mass and (multiple) NUT charges as being associated to distinct solutions of the rotation-deformed radial equation, which is made explicit in Cartesian multi-Kerr-Schild coordinates. This interpretation extends to electromagnetism with magnetic-type charges, and also extends to higher-spin counterparts, in accordance with the classical double or multi copy. We then establish a notion of ``electric-magnetic" duality in higher dimensions, relating mass/electric to NUT/magnetic charges, which generalises the D=4 case in a novel manner. For D≥6, this involves the choice where the multiple magnetic charges are equal. The duality is revealed in momentum space, by the 3-point scattering amplitudes that generate the solutions. For all spins, these amplitudes are constructed from a spin-raising operator \mathcal Sμ and take the form εμ1⋯μs\mathcal Sμ1⋯ \mathcal Sμs acting on a scalar seed. The scalar seed of the electric sector is dual to that of the magnetic sector: where the former's rotation dependence resums to a Bessel function J(D-5)/(2), the latter resums to a Bessel function J-(D-5)/(2). Finally, we explore the notion of self-duality that arises from this picture. Studying the classical 2 ↦ 2 amplitudes that determine leading-order scattering, we find no evidence of a higher-dimensional analogue of the integrability of D=4 self-dual gravity.