Probing anomalous Higgs couplings in $H \to Z V$ decays

TL;DR

This paper investigates rare Higgs decay processes to Z bosons and vector quarkonium to detect potential deviations from Standard Model predictions, using angular asymmetries as sensitive probes for new physics.

Contribution

It introduces a model-independent analysis of $H o Z V$ decays, highlighting the use of angular asymmetries to probe anomalous Higgs couplings in gauge and Yukawa sectors.

Findings

Branching fractions for $H o Z V$ are very small in the Standard Model.

Angular asymmetries can effectively reveal anomalous Higgs couplings.

Future LHC runs could observe these rare decays.

Abstract

We analyze the possibility of probing anomalous Higgs couplings in the rare decays $H \to Z V$, $V$ being a vector quarkonium state. These rare decays involve both gauge as well as the Yukawa sectors and either of them can potentially be anomalous. We show that the branching fractions for $H \to Z V$ decays in Standard Model are small, making it a sensitive probe for anomalous Higgs couplings originating from physics beyond Standard Model. Moreover, as both $V$ and $Z$ can decay into pair of charged leptons, they provide experimentally clean channels and future LHC runs should observe such decays. We perform a model independent analysis and show how angular asymmetries can be used to probe these anomalous Higgs couplings, taking further decays of $V$ and $Z$ to pair of charged leptons into account. The angular asymmetries can provide significant information about anomalous Higgs couplings in both gauge and Yukawa sectors.