Publications by Andrea Guerrieri

QCD worldsheet axion from the bootstrap

The worldsheet axion plays a crucial role in the dynamics of the Yang-Mills confining flux tubes. According to the lattice measurements, its mass is of order the string tension and its coupling is close to a certain critical value. Using the S-matrix Boots ...

Springer Nature2024

S-matrix bootstrap for effective field theories: massless pions

João Miguel Augusto Penedones Fernandes, Andrea Guerrieri

We use the numerical S-matrix bootstrap method to obtain bounds on the two leading Wilson coefficients (or low energy constants) of the chiral lagrangian controlling the low-energy dynamics of massless pions. This provides a proof of concept that the numer ...

Springer Nature2021

Flux Tube S-Matrix Bootstrap

João Miguel Augusto Penedones Fernandes, Andrea Guerrieri, Aditya Hebbar

We bootstrap the S matrix of massless particles in unitary, relativistic two dimensional quantum field theories. We find that the low energy expansion of such S matrices is strongly constrained by the existence of a UV completion. In the context of flux tu ...

2019

Bootstrapping QCD Using Pion Scattering Amplitudes

João Miguel Augusto Penedones Fernandes, Andrea Guerrieri

We consider the S-matrix bootstrap of four-dimensional scattering amplitudes with O(3) symmetry and no bound states. We explore the allowed space of scattering lengths which parametrize the interaction strength at threshold of the various scattering channe ...

2019