Measurement of the Higgs boson coupling properties in the $H\rightarrow ZZ^{*} \rightarrow 4\ell$ decay channel at $\sqrt{s}$ = 13 TeV with the ATLAS detector

TL;DR

This paper measures the Higgs boson’s coupling properties in the four-lepton decay channel at 13 TeV using ATLAS data, providing cross sections, coupling modifiers, and constraints on non-Standard-Model interactions.

Contribution

It presents the first detailed measurement of Higgs couplings and tensor structure in the $H ightarrow ZZ^* ightarrow 4 ext{l}$ channel at 13 TeV, including constraints on non-Standard-Model couplings.

Findings

Measured the inclusive cross section times branching ratio as 1.73 pb.

Placed constraints on CP-even and CP-odd couplings to Z bosons.

Compared measurements with Standard Model predictions, finding consistency within uncertainties.

Abstract

The coupling properties of the Higgs boson are studied in the four-lepton decay channel using 36.1 fb$^{-1}$ of $pp$ collision data from the LHC at a centre-of-mass energy of 13 TeV collected by the ATLAS detector. Cross sections are measured for the four key production modes in several exclusive regions of the Higgs boson production phase space and are interpreted in terms of coupling modifiers. The inclusive cross section times branching ratio for $H \rightarrow ZZ^*$ decay and for a Higgs boson absolute rapidity below 2.5 is measured to be $1.73^{+0.24}_{-0.23}$(stat.)$^{+0.10}_{-0.08}$(exp.)$\pm 0.04$(th.) pb compared to the Standard Model prediction of $1.34\pm0.09$ pb. In addition, the tensor structure of the Higgs boson couplings is studied using an effective Lagrangian approach for the description of interactions beyond the Standard Model. Constraints are placed on the non-Standard-Model CP-even and CP-odd couplings to $Z$ bosons and on the CP-odd coupling to gluons.