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arXiv · 2608.05272

Tree-Level Factorization Obstruction in Monopole Production

Hsing-Yi Lai·John Terning
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Abstract

We show that the tree-level amplitude for producing a monopole--antimonopole pair from an electrically charged pair cannot be constructed from the minimal one-photon couplings. Gluing the electric and magnetic three-point vertices gives a nonzero photon-pole contribution, but the resulting magnetic final state has the opposite discrete-symmetry eigenvalue from the electric initial state. Local four-point interactions cannot change the pole contribution fixed by the three-point couplings, so they cannot repair this mismatch. For fermions, the obstruction is specific to the minimal three-point coupling: an independent Pauli form factor supplies a spin-singlet three-point amplitude and allows the symmetry selection rule to be satisfied.

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Hsing-Yi Lai, John Terning. 2026-08-05. Tree-Level Factorization Obstruction in Monopole Production. https://arxiv.org/abs/2608.05272

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