Probing New Physics in Higgs Couplings to Fermions using an Angular Analysis

TL;DR

This paper proposes using the angular analysis of the decay $H o VZ$ to detect and measure potential parity-odd pseudoscalar couplings of the Higgs to quarks, providing a new method to probe Higgs-fermion interactions.

Contribution

It introduces a novel experimental approach to distinguish parity-even and parity-odd Higgs-quark couplings via angular distributions in rare Higgs decays.

Findings

Angular distributions can separate P-even and P-odd couplings.

The decay channel is experimentally clean at high-luminosity colliders.

Potential to measure Higgs-fermion parity properties.

Abstract

The standard-model Higgs boson couples to quarks through a parity-even scalar $Hq{\bar q}$ coupling. We show that the rare Higgs decay $H\to VZ$, where $V$ is a vector quarkonium state such as $J/\psi$ ($c{\bar c}$) or $\Upsilon(1S)$ ($b{\bar b}$), can be used to search for the presence of a parity-odd pseudoscalar $Hq{\bar q}$ coupling. Since both $V$ and $Z$ can decay to a pair of charged leptons, this presents an experimentally-clean channel that can be observed at the high-luminosity LHC or a future hadron collider. The P-even and P-odd $Hq{\bar q}$ couplings can be measured by analyzing the angular distribution of the final-state leptons.