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`The nucleon sigma terms in chiral perturbation theory' 

Abstract: I will show some recent results on the sigma-terms as they are
obtained in chiral perturbation theory using pi-N scattering data
or LQCD results on the baryon masses. In the former case, we present
a novel chiral representation of the pi-N scattering amplitude
(arXiv:1110.3797[hep-ph]) that succeeds to provide a comprehensive description
of the phenomenology associated with the different partial wave parametrizations
of the experimental data. Therefore, we discuss the values of the pion-nucleon
sigma terms obtained from the Karlsruhe-Helsiki, George-Washington and Matsinos`
analyses in connection with the corresponding results for the pi-N phase shifts,
the pi-N-Delta coupling, the Goldberger-Treiman relation and the scattering
lengths. The consistency with the information provided by alternative
experimental sources such as pionic-atoms or NN interaction is also discussed.
Our analysis suggests that modern experimental data favors a relatively large
value of the pion-nucleon sigma term, namely sigma_{pi-N}=59(7)MeV.
I will also present the results that can be obtained in the pion-nucleon
and strange sigma terms by extrapolating recent N_f=2+1 LQCD results and
using the Hellmann-Feynman theorem.

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