The SMEFT formalism: the basis for finding deviations from the Standard Model

The search for manifestations of physics beyond the Standard Model (SM) is one of the main directions of research at the LHC and future colliders under discussion. The effects caused by the new physics can consist in the direct detection of new particles if their masses are less than the characteristic energies available at colliders and their interactions with the SM particles are strong enough. But if the masses of new particles are too large, or the interactions with SM particles are too weak, then new particles cannot be detected directly. In this case, the new physics can lead to a modification of the interactions of SM particles, to subthreshold effects. We present„ the current status of an approach or formalism called the Standard Model Effective Field Theory (SMEFT), which allows„ us to describe and model deviations from the SM predictions in a theoretically consistent manner. The advantages of and serious problems with this approach are discussed.