Higgs couplings in SMEFT via Zh production at the HL-LHC

We study the Higgs couplings present in the $Zh$ associated production mode at the Large Hadron Collider (LHC) in presence of both CP even and CP odd dimension 6 Standard Model Effective Theory (SMEFT) operators. The analysis is performed mainly in context of the HL-LHC (with √s=14 TeV and luminosity 3000 fb⁻¹) setup using cut based as well as machine learning techniques. The analysis shows significant betterment in the signal significance by using the machine learning technique. We also do a χ² analysis, which reveals a significant change in the sensitivity of the coupling modifiers due to the presence of effective operators, in particular due to the four point $qqZh$ interaction. The presence of dimension six CP odd four point operators, which contributes at O (Λ⁻⁴) order due to lack of interference with the SM contributions, can only have sensitivity with smaller NP scale at the HL-LHC, after addressing the effective limit and constraints.