ArXiv (30') + Presentation (30') [by Andrea, title: “From data to the analytic S-matrix”]

Abstract: In this talk I will discuss our attempt of understanding the QCD spectrum in detail using the available experimental data.
To do so, we develop a fit strategy that combines the S-matrix Bootstrap with non-convex optimization methods, and apply our algorithm to the case of \pi\pi scattering. The fitted amplitude correctly predicts the low energy ChiPT behavior, the experimental total cross sections at higher energy, and the physical spectrum up to 1.4 GeV (above that energy we need more precision). Surprisingly, Bootstrap predicts an additional tetraquark state, not yet observed, and that could be investigated in the decay of the B+ ->pi+ p+ pi- at LHCb.

Reference: https://arxiv.org/pdf/2410.23333