Nonlinear gauge-Higgs <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>C</mml:mi><mml:mi>P</mml:mi></mml:math> violation

A critical element of the LHC physics program is the search for an additional source of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>C</a:mi><a:mi>P</a:mi></a:math> violation. This is largely unexplored in the context of nonlinear Higgs physics, which is naturally described in Higgs effective field theory (HEFT). Relevant new higher-dimensional operators modify the production rate and branching ratios of the Higgs boson, decorrelating different Higgs multiplicities. In this work, we consider single Higgs and Higgs pair production via weak boson fusion from the perspective of gauge-Higgs <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>C</c:mi><c:mi>P</c:mi></c:math> violation through the lens of Higgs nonlinearity. This generalizes existing rate-based searches and analyses by the ATLAS and CMS experiments. Particular focus is given to the phenomenological differences in the expected beyond Standard Model (BSM) sensitivity pattern when comparing HEFT constraints with Standard Model effective field theory (SMEFT) limits. Published by the American Physical Society 2024