Speaker
Description
The non-observation of heavy particles at the LHC suggests the existence of an energy gap between collider scales and the scale of new physics. Therefore, Effective Field Theories (EFTs) provide a useful framework to describe BSM effects. The study of diboson production, $pp\to VW$, and associated Higgs production with a vector boson $pp\to Vh$, where $V=Z,W$, provides powerful probes of EFTs at the LHC, as these processes receive contributions that grow with the center-of-mass energy from certain dimension-six operators, leading to stronger bounds than those from LEP-I and LEP-II in certain cases. Previous studies of these processes often relied on very restrictive flavor assumptions, where the constraints are driven by contributions from light-quark operators due to Parton Distribution Functions (PDFs). However, the high precision of present and future LHC and HL-LHC searches allows us to study new physics effects involving heavy-quark operators as well. In this work, we relax these flavor assumptions and investigate how associated Higgs and diboson production can be constrained by present and future searches assuming a general flavor structure. We also explore the complementarity between high-energy observables and low-energy flavor constraints, considering combined fits involving different energy scales.
To illustrate this discussion, we consider unitarity tests of the first row of the CKM matrix. We update the constraints from $pp\to Vh$ and $pp\to VW$ using the most recent LHC data and show that high-energy searches can provide bounds that are competitive with those from flavor observables for charged-current transitions.
