S-matrix Bootstrap: from theory to phenomenology

by Prof. Andrea Guerrieri (City St. George’s, Univ. of London)

Wednesday 18 Feb 2026, 10:45 → 12:00 Europe/Berlin

A.1.01 - Alps Süd (MPP)

The space of relativistic scattering amplitudes is tightly constrained by general principles such as causality, unitarity, and analyticity. The S-matrix Bootstrap program aims to characterize this space directly, without reference to a specific Lagrangian, by exploiting these constraints using modern and powerful tools from convex optimization. 

In this talk, I will discuss two applications of this approach. First, I will show how combining analytic methods with numerical bootstrap techniques allows one to upgrade the asymptotic Froissart bound into a quantitative, model-independent bound that is valid at all energies https://arxiv.org/pdf/2506.04313. Second, I will illustrate how incorporating experimental data into the bootstrap framework makes it possible to reproduce the known QCD spectrum and provides evidence for an unexpected tetraquark state https://arxiv.org/pdf/2410.23333, currently under investigation by the LHCb collaboration