# Probing multi-particle unitarity with the Landau equations

### Miguel Correia, Amit Sever, Alexander Zhiboedov

Miguel Correia, Amit Sever, Alexander Zhiboedov

**23/11/21**Published in : arXiv:2111.12100

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.