Analyzing the CP Nature of a New Scalar Particle via S->Zh Decay

TL;DR

This paper investigates how the decay of a new scalar particle into Z and Higgs bosons can reveal its CP properties, using an effective field theory approach to analyze the decay's dependence on CP-odd interactions.

Contribution

It provides a model-independent analysis of the $S\to Zh$ decay to determine the CP nature of scalar particles using effective Lagrangians and one-loop Wilson coefficients.

Findings

$S\to Zh$ decay occurs only if $S$ has CP-odd interactions.

Computed Wilson coefficients from heavy fermion loops.

Decay analysis offers a probe of CP violation in scalar sector.

Abstract

Scalar particles $S$ which are singlets under the Standard Model gauge group are generic features of many models of fundamental physics, in particular as possible mediators to a hidden sector. We show that the decay $S\to Zh$ provides a powerful probe of the CP nature of the scalar, because it is allowed only if $S$ has CP-odd interactions. We perform a model-independent analysis of this decay using an effective Lagrangian and compute the relevant Wilson coefficients arising from integrating out heavy fermions to one-loop order.