Model-independent Higgs coupling measurements at the LHC using the H \to ZZ \to 4l lineshape

TL;DR

This paper presents a model-independent method to measure Higgs couplings at the LHC by combining width measurements from the H → ZZ → 4l lineshape with signal rate data, enabling precise coupling extraction.

Contribution

It introduces a novel approach that combines width and rate measurements to determine Higgs couplings without relying on specific models.

Findings

Couplings to WW, ZZ, and gg can be measured with about 10% precision.

A 95% CL upper limit of 22% on unobserved decay width component.

Method applicable to heavier Higgs masses.

Abstract

We show that combining a direct measurement of the Higgs total width from the H \to ZZ \to 4l lineshape with Higgs signal rate measurements allows Higgs couplings to be extracted in a model-independent way from CERN Large Hadron Collider (LHC) data. Using existing experimental studies with 30 fb-1 at one detector of the 14 TeV LHC, we show that the couplings-squared of a 190 GeV Higgs to WW, ZZ, and gg can be extracted with statistical precisions of about 10%, and a 95% confidence level upper limit on an unobserved component of the Higgs decay width of about 22% of the SM Higgs width can be set. The method can also be applied for heavier Higgs masses.