Impact of NLO Weak SMEFT Corrections in $e^+e^- \rightarrow ZH$

TL;DR

This paper provides a comprehensive NLO analysis of the $e^+e^- ightarrow ZH$ process within SMEFT, highlighting new CP-violating effects and the importance of multi-scale measurements for constraining new physics.

Contribution

It presents the first complete NLO calculation of $e^+e^- ightarrow ZH$ in SMEFT, including all dimension-6 operators and their complex dependencies.

Findings

NLO corrections introduce novel CP-violating dependencies.

Renormalization group logarithms alone can be misleading.

Combining measurements at different energies enhances constraints.

Abstract

We present results from a complete next-to-leading order (NLO) calculation of $e^+e^-\rightarrow ZH$ in the Standard Model Effective Field Theory (SMEFT) framework, including all contributions from dimension-6 operators. At NLO, there are novel dependencies on CP violating parameters in the gauge sector, on modifications to the Higgs boson self-couplings, on alterations to the top quark Yukawa couplings, and on 4-fermion operators involving the electron and the top quark, among others. We show that including only the logarithms resulting from renormalization group scaling can produce misleading results, and further, we explicitly demonstrate the constraining power of combining measurements from different energy scales.