#StudentSeminar: Pion electro- and photoproduction on nucleons in a covariant Chiral Perturbation Theory

por Gustavo Guerrero (IFIC)

jueves 29 abr. 2021 15:00 → 16:00 Europe/Madrid

Universe

I review some recent studies made on pion electro- and photoproduction off nucleons close to threshold within a relativistic Chiral Perturbation Theory, the effective field theory of hadrons at low energies based on the symmetries of QCD.

We observe that \Delta(1232) degrees of freedom in the model improves the global agreement with experimental data for the neutral pion production channel. The charged pion channels has been found to be dominated by the nucleon sector. Furthermore, I implement a fitting procedure for the relevant parameters of the model, allowing us to explore kinematical regions for different observables that should be unsolved in QCD.

Moreover, we have found a best conciliation near threshold pion production with some other parameters that were fixed by other processes, like pion-nucleon scattering, when we consider the isospin breaking at the one-loop amplitudes. We reproduce accordingly the angular distributions and the energy dependence up to ~60 MeV above the threshold for all the observables.

Finally, I will show some applications of these studies incorporated in other precision processes  involving neutrino-nucleon interactions or pion photoproduction on nucleus.