Mesons, Large N and Positivity
Fundamental principles, including analyticity, crossing symmetry, and unitarity, combined with the behavior of scattering amplitudes at high energies, impose significant constraints on the landscape of quantum field theories. This talk will review recent advancements in leveraging positivity constraints to explore the space of scattering amplitudes. These techniques will be applied to investigate and potentially constrain large-N QCD. Additionally, their implications for the weak gravity conjecture will be examined.