Complete two-loop unrenormalized electroweak corrections to e + e − → H Z

We compute the complete two-loop unrenormalized electroweak corrections to the Higgsstrahlung process <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:mo stretchy="false">→</a:mo> <a:mi>H</a:mi> <a:mi>Z</a:mi> </a:math> at future Higgs factories. Our result for a given center-of-mass energy is expressed as a piecewise function defined by several deeply expanded power series, which has high precision and can be further manipulated efficiently. We find that the finite part of the unrenormalized two-loop electroweak corrections can contribute a few thousandths, which might indicate their importance to match the precision of future Higgs factories. This work represents the first complete calculation of the unrenormalized two-loop electroweak corrections for processes with four external particles.