[Theory-seminars] Theory seminar next week

[Astrid Hiller Blin]

Dear all,

Here is a reminder of next week's theory seminar:

*Theory seminar*
Monday October 5, 1:00 PM

*Gustavo Guerrero Navarro* (University of Valencia) will talk about "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.

Bluejeans connection: https://bluejeans.com/801786278
<https://urldefense.proofpoint.com/v2/url?u=https-3A__bluejeans.com_801786278&d=DwMFaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=AIMSQQ81YDyrZuJNGks2qw&m=aT_3J5jjiFmHtFXffqbfPqEY_A73NEWw2ebyFyL_eCA&s=YNm3qgT5e8sJgKfZ9vFA_w--imuXwmeAjg0C4AslLwg&e=>

Best wishes,
Astrid, Christos, Filippo, Miguel
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