Speaker
Description
In this talk, I will point out the relevance of a new class of model-independent higher-order contributions to the trilinear and quartic self-couplings of the detected Higgs boson giving rise to potentially large effects of physics beyond the Standard Model (SM). It consists of SM-like diagrams with insertions of loop-corrected values for the trilinear and quartic Higgs self-couplings. While up to now predictions in specific models of physics beyond the SM were only evaluated up to the one-loop or, in some cases, up to the two-loop level, potentially large higher-order contributions can consistently be incorporated into existing one-loop or two-loop predictions. These model-independent higher-order contributions therefore improve the existing predictions that were obtained in specific models. Confronting the predictions with the relevant experimental results and theoretical constraints, a simultaneous determination of the trilinear and quartic Higgs-boson self-couplings is performed. The new set of model-independent higher-order contributions can then induce sizeable shifts in the inferred bounds on the trilinear and quartic Higgs self-couplings. For example, including the new higher-order corrections can shift the upper bound on the trilinear self-coupling modifier entering the theoretical predictions to $\sim4.9$, from the experimental limit of $6.1$. The results demonstrate that incorporating these higher-order contributions is essential for a consistent interpretation of present and future measurements. I will finally present a public tool that implements these effects and enables direct comparison with experimental limits.