Probing SMEFT predictions and effects beyond SMEFT in semileptonic processes

Speaker: Ph.D. Siddhartha Karmakar (Tata Institute, Mumbai)
Date/Time: Wednesday 9 October 2024, 14:15
Room: Theresienstr. 37, A318

Title: Probing SMEFT predictions and effects beyond SMEFT in semileptonic processes

Abstract:
The SU(2)xU(1) invariance of the Standard Model Effective Field Theory (SMEFT) imposes constraints on Wilson coefficients of U(1)em-invariant effective Lagrangians, such as the Low-energy Effective Field Theory (LEFT) for flavor-physics observables and the Higgs Effective Field Theory (HEFT) for weak-scale observables. In this work, we derive all such constraints for semileptonic operators up to dimension 6, resulting in 2223 linear relations among the HEFT/LEFT Wilson coefficients, independent of mass or flavor basis alignment. These relations connect various experimental searches, including high-pT di-lepton searches, top decays, Z-pole observables, neutrino oscillations, and semileptonic decays of B, K, and D mesons, allowing for indirect constraints on Wilson coefficients currently weakly constrained or unconstrained by direct experiments. We also explore how correlated anomalies may arise across channels if new physics is detected in some particular channels, and propose flavor observables from baryonic and mesonic decays that can distinguish effects beyond SMEFT from other new physics scenarios.