Search for anomalies in vector-boson fusion production of the Higgs boson in $H(\rightarrow \gamma\gamma) jj$ events using 164 fb$^{-1}$ of $pp$ collision data collected at $\sqrt{s}=13.6$ TeV with the ATLAS detector

TL;DR

This paper investigates Higgs boson properties in vector-boson fusion events using ATLAS data, employing advanced analysis techniques to test for deviations from the Standard Model, and finds results consistent with the Standard Model predictions.

Contribution

It introduces a neural network-based classification method and combines multiple analyses to improve constraints on Higgs couplings and CP-odd interactions.

Findings

Results are consistent with the Standard Model

Enhanced sensitivity through neural network classification

Improved constraints on CP-odd couplings

Abstract

This article details two studies of Higgs boson properties using the vector-boson fusion production mode and the $\gamma\gamma jj$ final state. Both efforts are based on a data sample corresponding to 164 fb$^{-1}$ of $\sqrt{s}=13.6$ TeV proton--proton collisions recorded by the ATLAS experiment at the Large Hadron Collider. The first study employs matrix element-based optimal observables to constrain CP-odd couplings beyond the Standard Model within the Standard Model Effective Field Theory framework, expressed in the Warsaw basis. The second study exploits angular distributions to probe the Higgs boson's couplings to longitudinally and transversely polarised $W$ and $Z$ bosons in the production of the Higgs boson. To maximise the sensitivity, the constraints of the CP-odd couplings are combined with those from a previous analysis performed in $\gamma\gamma jj$ events in a data sample of proton--proton collisions at $\sqrt{s}=13$ TeV, corresponding to an integrated luminosity of 140 fb$^{-1}$. A significant improvement with respect to the previous analysis is achieved through the implementation of a new neural network-based classification algorithm. All measurements are in agreement with the Standard Model prediction of a CP-even Higgs boson with the expected relative coupling strengths to longitudinally and transversely polarised vector bosons.