Work

Perturbative unitarity calls for an action

Year: 2025

Type: article

Abstract: In this work, we investigate the consistency of a perturbative definition of the S-matrix in a particular class of non-Lagrangian theories. We focus on the p -form theories proposed in the work by Broccoli [], which are fully defined by “third-way” consistent equations of motion. Using the perturbiner method, we show that the unitarity is absent even at the tree level. We then pin down a unique modification of the equations of motion that restores unitarity. The tradeoff is the reinstatement of an underlying Lagrangian, which we recognize as the higher-dimensional generalization of the Freedman-Townsend (FT) model. Finally, we discuss conserved currents in third-way theories and show they all follow from parent currents in the FT model. In particular, we point out the existence of a higher-ranked global symmetry, which signals that the FT model is compatible with the existence of branelike charged objects in higher dimensions.

Source: Physical review. D/Physical review. D.

DOI: 10.1103/pktc-9rfv

Authors: Subhroneel Chakrabarti, Renann Lipinski Jusinskas

Institution: FZU - Institute of Physics of the Czech Academy of Sciences

Language: English

Topic: Black Holes and Theoretical Physics

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid