Trilinear Higgs coupling determination via single-Higgs differential measurements at the LHC

TL;DR

This paper investigates how one-loop effects of an anomalous Higgs trilinear coupling influence Higgs decay and production rates at the LHC, using differential measurements to improve coupling determination.

Contribution

It introduces a public code for reweighting Standard-Model-like events to include anomalous Higgs trilinear effects and assesses the potential of differential measurements for constraining the coupling.

Findings

Differential effects are significant in VBF, VH, and tHj channels.

Electroweak corrections are included for relevant channels.

Sensitivity depends on experimental and theoretical uncertainties.

Abstract

We study one-loop effects induced by an anomalous Higgs trilinear coupling on total and differential rates for the $H\to 4\ell$ decay and some of the main single-Higgs production channels at the LHC, namely, VBF, $VH$, $t\bar tH$ and $tHj$. Our results are based on a public code that calculates these effects by simply reweighting samples of Standard-Model-like events for a given production channel. For $VH$ and $t\bar tH$ production, where differential effects are particularly relevant, we include Standard Model electroweak corrections, which have similar sizes but different kinematic dependences. Finally, we study the sensitivity of future LHC runs to determine the trilinear coupling via inclusive and differential measurements, considering also the case where the Higgs couplings to vector bosons and the top quark is affected by new physics. We find that the constraints on the couplings and the relevance of differential distributions critically depend on the expected experimental and theoretical uncertainties.