2013/07/31 by Yu-tin Huang, David A. McGady, David McGady · 14 citations
Mathematics · Physics and Astronomy · #Black Holes and Theoretical Physics #Consistency (knowledge bases) #Cosmology and Gravitation Theories #Discrete mathematics #Gauge (firearms) #Materials science #Mathematics #Noncommutative and Quantum Gravity Theories #Particle physics #Physics #Unitarity #hep-th
paper · pdf · doi:10.1103/physrevlett.112.241601
published in Physical Review Letters 112(24), 241601 (American Physical Society) · V2: Typos corrected and Improved discussions
arxiv created 2014/02/27 · openalex publication_date 2014/06/18 · arxiv updated 2014/06/25 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
In the modern on-shell approach, the perturbative S matrix is constructed iteratively using on-shell building blocks with manifest unitarity. As only gauge invariant quantities enter in the intermediate steps, the notion of a gauge anomaly is absent. In this Letter, we rephrase the anomaly cancellation conditions in a purely on-shell language. We demonstrate that while the unitarity methods automatically lead to a unitary S matrix, the rational terms that are required to enforce locality, invariably give rise to inconsistent factorization channels in chiral theories. In four dimensions, the absence of such inconsistencies implies the vanishing of the symmetric trace of three generators. In six dimensions, if the symmetric trace of four generators does not vanish, the rational term develops a factorization channel revealing a new particle in the spectrum: the 2-form of the Green-Schwarz mechanism. Thus, in the purely on-shell construction, the notion of a gauge anomaly is replaced by the difficulty to consistently impose locality on the unitary S matrix.