Off diagonal charged scalar couplings with the Z boson: the Zee model as an example

TL;DR

This paper investigates off-diagonal Z boson couplings with charged scalars in models like the Zee model, highlighting their phenomenological importance and proposing experimental searches at the LHC.

Contribution

It provides a detailed analysis of off-diagonal scalar couplings in models with scalar doublets and singlets, emphasizing their overlooked role in phenomenology and proposing specific LHC search strategies.

Findings

Off-diagonal Z couplings can significantly affect scalar decay processes.

Benchmark points compatible with current data are identified for LHC searches.

Proposes new search channels for charged scalars at the LHC.

Abstract

Models with scalar doublets and charged scalar singlets have the interesting property that they have couplings between one $Z$ boson and two charged scalars of different masses. This property is often ignored in phenomenological analysis, as it is absent from models with only extra scalar doublets. We explore this issue in detail, considering $h \rightarrow Z \gamma$, $B \to X_s \gamma$, and the decay of a heavy charged scalar into a lighter one and a $Z$ boson. We propose that the latter be actively searched for at the LHC, using the scalar sector of the Zee model as a prototype and proposing benchmark points which obey all current experimental data and could be within reach of the LHC.