In our recent paper “Impact of New Physics on Momentum-Dependent Particle Widths and Propagators” we investigate how momentum-dependent widths and propagators influence gauge and Higgs bosons, along with the top quark, within the Standard Model (SM) and its SMEFT (Standard Model Effective Field Theory) extensions. We analyse these effects using perturbative resummation techniques. A notable finding is the significant sensitivity of the top quark to such effects near its mass threshold, highlighting the potential of future high-precision lepton colliders to constrain SMEFT Wilson coefficients effectively. These insights provide deeper understanding of particle behavior and contribute to probing new physics beyond the SM. (Read more)