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arXiv · 2601.16452

BRST methods for constructing quartic actions for spinning black holes

Julian Lang·Mirian Tsulaia
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Abstract

We develop a systematic approach to the computation of gauge invariant quartic interactions between reducible massive and massless higher spin fields. Extending the BRST formulation of existing cubic results, we obtain a single constraint for each off-shell quartic vertex that ensures both the gauge invariance of the Lagrangian and associativity of the gauge transformations at quartic order. A solution to these equations is presented. The general equation is then reduced to an on-shell version to reduce complexity. We find example solutions for the off-shell and on-shell quartic vertices in low spin examples relevant to the problem of black hole scattering.

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Julian Lang, Mirian Tsulaia. 2026-01-23. BRST methods for constructing quartic actions for spinning black holes. https://arxiv.org/abs/2601.16452

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