[Theory-seminars] Theory seminar on Monday Oct. 5th, plus farewell for Ishara (starts at 12:40)

[Christos Kallidonis]

Dear all,

Tomorrow we will have a Theory Seminar starting at 13:00.
At 12:40, you main join for a farewell to Ishara Fernando, to wish him good luck in his new position at Fermilab.

Please see below for the details of the seminar:

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Bluejeans connection: https://bluejeans.com/801786278
Date and time: Monday October 5th, 13:00
Speaker: Gustavo Guerrero Navarro (University of Valencia)
Title: Pion electro- and photoproduction on nucleons with explicit Delta(1232) in covariant Chiral Perturbation Theory
Abstract: Recent studies have been made on pion electro- and photoproduction off nucleons close to threshold with the explicit inclusion of the Delta(1232) in full relativistic Chiral Perturbation Theory at O(p^3). The relevant low energy constants (LECs) were fixed by fitting the available experimental data with the theoretical model.
The Delta(1232) inclusion in the model improves the global agreement with data in the neutral and charged pion photoproduction. Furthermore, when we extend the fitting procedure to the electroproduction case, the model remains consistent with data, also allowing us to explore wider kinematical regions being important to better determine the LECs.
Moreover, we have found a best conciliation near threshold with the LECs 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 center of mass energy dependence up to ~60 MeV above the threshold for all the observables.
Finally, I show a brief study for the uncertainties in the fitted LECs from three main sources of error: The systematical errors in the theoretical model, the statistical errors from data, and the error bars from the non-fitting low-energy-constants. These LECs could be incorporated in the study of other precision processes involving neutrino-nucleus interactions or pion photoproduction on nucleus.
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See you all there!

Best regards,
Astrid, Christos, Filippo
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