Systematic derivation of perturbative unitarity bounds for any models

Abstract

In this letter, we provide a simple algorithm, anyPUB, to systematically derive the $2\to 2$ scattering matrix in the high-energy limit for any kind of models, irrespective of their gauge group or their field representation. After computing the eigenvalues analytically and/or numerically from this matrix, we impose perturbative unitarity bounds on them. We tested our method on various models and validated the results against the literature. Finally, as a concrete application of our approach, we discuss the case of the minimal left-right symmetric model and derive, for the first time, the perturbative unitarity constraints in the Pati-Salam model.

Comments: 7 pages, 2 figures. Version accepted for publication in PLB. The package anyPUB can be downloaded at https://github.com/nicobenincasa/anyPUB