Probing Extended Scalar Sectors with Precision $e^+e^-\to Zh$ and Higgs Diphoton Studies

TL;DR

This paper calculates one-loop corrections to the Higgsstrahlung process in extended scalar sectors and explores how future electron-positron colliders can probe new scalar particles through precision measurements, complementing collider searches.

Contribution

It provides a detailed analysis of one-loop corrections in various extended scalar models and assesses their detectability via future collider precision and Higgs diphoton decay measurements.

Findings

Future $e^+e^-$ colliders can probe extended scalar sectors at sub-percent precision.

Higgs diphoton decay rates offer complementary sensitivity to scalar sector extensions.

Complex triplet models show particularly strong combined sensitivity from both methods.

Abstract

We compute the one-loop corrections to $\sigma(e^+ e^- \to Z h)$ arising from representative extended Standard Model scalar sector scenarios. According to the new scalar $\mathrm{SU(2)_L}$ representations, we consider the inert doublet, real and complex triplet, quintuplet, and septuplet models. With the sub-percent level precision expected for prospective future $e+e-$ collider measurements of $\sigma(e^+ e^- \to Z h)$, studies of the Higgsstrahlung process will probe extended scalar sector particle spectrum and interactions in a manner complementary to direct searches at the Large Hadron Collider and possible future $pp$ colliders. We also compare with the sensitivity of future Higgs diphoton decay rate measurements. We find that the $\sigma(e^+ e^- \to Z h)$ and $\Gamma(h\to\gamma\gamma)$ complementarity is particularly pronounced for the complex triplet model.