Higgs Self-Coupling at the Future Circular e+e− Collider

Single Higgs production at FCC-ee probes the Higgs self-coupling at next-to-leading order (NLO). Extracting a bound requires a global analysis accounting for other possible new physics contributions up to NLO. We determine the FCC-ee sensitivity to Higgs self-coupling modifications <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>δ</a:mi><a:msub><a:mi>κ</a:mi><a:mi>λ</a:mi></a:msub></a:math> within the standard model effective field theory framework, including for the first time flavor, LEP, LHC, and FCC-ee observables in a global analysis with all leading NLO effects via one-loop renormalization group evolution, as well as incorporating finite NLO contributions to electroweak precision and <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>Z</c:mi><c:mi>H</c:mi></c:math> observables. The global sensitivity to <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mi>δ</e:mi><e:msub><e:mi>κ</e:mi><e:mi>λ</e:mi></e:msub></e:math> is estimated by marginalizing over the effects of all other operators, bringing flavor considerations to the fore. We find that, under reasonable assumptions, FCC-ee sensitivity to <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mi>δ</g:mi><g:msub><g:mi>κ</g:mi><g:mi>λ</g:mi></g:msub></g:math> can exceed that of the HL-LHC.