Seminar 
Title: Sigma term physics 
Speaker: Prof. Ulf-G. Meissner (Universit at Bonn & Forschungszentrum Julich) 
Time: 3:00 PM,Jul.16th (Tuesday), 2019 
Place: R319, Theoretical Physics Division 

Abstract:
The pion-nucleon sigma term σπN is an important quantity in strong interaction phenomenology and in searches for physics beyond the Standard Model. After a broad introduction, the speaker will discuss its precise extraction from pion-nucleon scattering data based on Roy-Steiner equations. In this context, tensions with recent lattice determination of σπN are discussed. Then, he will turn to the flavor decomposition of the sigma term and the question of strangeness in the nucleon. Using different variants of baryon chiral perturbation theory, he will discuss the present understanding and future improvements.