Top and beauty synergies in SMEFT-fits at present and future colliders

Abstract

Abstract We perform global fits within Standard Model Effective Field Theory (SMEFT) combining top-quark pair production processes and decay with b → s flavor changing neutral current transitions and Z → $$ b\overline{b} $$ b b ¯ in three stages: using existing data from the LHC and B-factories, using projections for the HL-LHC and Belle II, and studying the additional new physics impact from a future lepton collider. The latter is ideally suited to directly probe ℓ+ℓ− → $$ t\overline{t} $$ t t ¯ transitions. We observe powerful synergies in combining both top and beauty observables as flat directions are removed and more operators can be probed. We find that a future lepton collider significantly enhances this interplay and qualitatively improves global SMEFT fits.