The $e^+ e^- \rightarrow Z H$ Process in the SMEFT Beyond Leading Order

Konstantin Asteriadis; Sally Dawson; Pier Paolo Giardino; Robert Szafron

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arXiv · 2409.11466

The $e^+ e^- \rightarrow Z H$ Process in the SMEFT Beyond Leading Order

Konstantin Asteriadis·Sally Dawson·Pier Paolo Giardino·Robert Szafron

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Abstract

We systematically study potential effects of Beyond the Standard Model physics in the $e^+ e^- \rightarrow Z H$ process. To this end, we include all relevant dimension-6 Standard Model Effective Field Theory operators and work to next-to-leading order (NLO) accuracy in the electroweak coupling. We consider both polarized and unpolarized electron and positron beams and present results for $\sqrt{s}=240, ~365$ and $500~{\rm GeV}$, emphasizing contributions where the NLO predictions differ significantly from the leading order results. At NLO, a sensitivity arises to operators that do not contribute at tree level, such as the Higgs tri-linear coupling, CP-violating operators, and dimension-6 operators involving the top quark, among many others. We compare the prospects of future $e^+e^-$ colliders to explore these new physics effects with existing measurements from the LHC, electron EDMs (for CP violating operators), and Z pole measurements.

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Konstantin Asteriadis, Sally Dawson, Pier Paolo Giardino, Robert Szafron. 2024-09-17. The $e^+ e^- \rightarrow Z H$ Process in the SMEFT Beyond Leading Order. https://arxiv.org/abs/2409.11466

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