# Probing multi-particle unitarity with the Landau equations

### Submission summary

 As Contributors: Miguel Correia Arxiv Link: https://arxiv.org/abs/2111.12100v1 (pdf) Date submitted: 2022-01-06 21:51 Submitted by: Correia, Miguel Submitted to: SciPost Physics Academic field: Physics Specialties: High-Energy Physics - Theory Approaches: Theoretical, Computational

### Abstract

We consider the $2\to 2$ scattering amplitude of identical massive particles. We identify the Landau curves in the multi-particle region $16m^2 \leq s, t < 36m^2$. We systematically generate and select the relevant graphs and numerically solve the associated Landau equations for the leading singularity. We find an infinite sequence of Landau curves that accumulates at finite $s$ and $t$ on the physical sheet. We expect that such accumulations are generic for $s,t > 16m^2$. Our analysis sheds new light on the complicated analytic structure of nonperturbative relativistic scattering amplitudes.

###### Current status:
Editor-in-charge assigned