Speaker
Description
The origin and flavor structure of the nucleon mass are fundamental questions in strong interaction physics. The nucleon sigma terms quantify the response of the nucleon mass to variations of the quark masses and provide direct access to its scalar matrix elements. We present a lattice QCD determination of the light, strange, and charm sigma terms using twisted-mass fermions at the physical pion mass and multiple lattice spacings. Both connected and quark disconnected contributions are included, with particular attention to excited-state contamination and the continuum extrapolation. Studying the three flavors within a common framework allows us to probe qualitatively different regimes of QCD, ranging from chiral dynamics in the light quark sector and sea quark effects for strangeness to the onset of heavy quark dynamics for charm. We discuss the flavor dependence of the scalar response of the nucleon and the associated systematic effects, providing a unified view of nucleon sigma terms from light to charm.