Electron g−2 foreshadowing discoveries at FCC-ee

A future <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msup><a:mi>e</a:mi><a:mo>+</a:mo></a:msup><a:msup><a:mi>e</a:mi><a:mo>−</a:mo></a:msup></a:math> circular collider (FCC-ee) may provide a unique probe of the electron Yukawa coupling through Higgs boson production on resonance. Motivated by this exciting possibility, we examine a simple model which can result in <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mrow><c:mi mathvariant="script">O</c:mi><c:mrow><c:mo stretchy="false">(</c:mo><c:mn>10</c:mn><c:mo stretchy="false">)</c:mo></c:mrow></c:mrow></c:math> modifications of the Higgs coupling to electrons. The model can also lead to deviations in the electron anomalous magnetic moment, <h:math xmlns:h="http://www.w3.org/1998/Math/MathML" display="inline"><h:mrow><h:msub><h:mrow><h:mi>g</h:mi></h:mrow><h:mrow><h:mi>e</h:mi></h:mrow></h:msub><h:mo>−</h:mo><h:mn>2</h:mn></h:mrow></h:math>, which at present shows a <j:math xmlns:j="http://www.w3.org/1998/Math/MathML" display="inline"><j:mrow><j:mo>+</j:mo><j:mn>2.2</j:mn><j:mi>σ</j:mi></j:mrow></j:math> or <l:math xmlns:l="http://www.w3.org/1998/Math/MathML" display="inline"><l:mrow><l:mo>−</l:mo><l:mn>3.7</l:mn><l:mi>σ</l:mi></l:mrow></l:math> deviation, implied by differing precision determinations of the electromagnetic fine structure constant. The electron <n:math xmlns:n="http://www.w3.org/1998/Math/MathML" display="inline"><n:msub><n:mi>g</n:mi><n:mi>e</n:mi></n:msub><n:mo>−</n:mo><n:mn>2</n:mn></n:math> can be a forerunner for FCC-ee discoveries which, as we elucidate, may not be accessible to the high-luminosity LHC measurements. A simple extension of our model can also account for the current deviation in the muon <p:math xmlns:p="http://www.w3.org/1998/Math/MathML" display="inline"><p:msub><p:mi>g</p:mi><p:mi>μ</p:mi></p:msub><p:mo>−</p:mo><p:mn>2</p:mn></p:math>. Published by the American Physical Society 2024