Resolving the tensor structure of the Higgs coupling to $Z$-bosons via Higgs-strahlung

Understand

We propose differential observables for $pp \to Z(\ell^+\ell^-)h(b\bar{b})$ that can be used to completely determine the tensor structure of the $hZZ^*/hZ\bar{f}f$ couplings relevant to this process in the dimension-6 SMEFT.

• In particular, we propose a strategy to probe the anomalous $h Z_{\mu \nu}Z^{\mu \nu}$ and $h Z_{\mu \nu}\tilde{Z}^{\mu \nu}$ vertices at the percent level.
• We show that this can be achieved by resurrecting the interference term between the transverse $Zh$ amplitude, which receives contributions from the above couplings, and the dominant SM longitudinal amplitude.
• These contributions are hard to isolate without a knowledge of the analytical amplitude, as they vanish unless the process is studied differentially in three different angular variables at the level of the $Z$-decay products.