The sensitivity of the Higgs boson branching ratios to the W boson width

TL;DR

This paper investigates how the Higgs boson decay into vector bosons depends on the W boson width, using LHC data to extract a value for Gamma W and highlighting its importance in Higgs coupling analyses.

Contribution

It introduces a method to determine the W boson width from Higgs decay ratios, emphasizing its impact on Higgs coupling measurements.

Findings

Extracted Gamma W = 1.8+0.4-0.3 GeV from LHC data.

Showed the sensitivity of Higgs decay ratios to the W boson width.

Highlighted the need to consider Gamma W in Higgs analyses.

Abstract

The Higgs boson branching ratio into vector bosons is sensitive to the decay widths of those vector bosons because they are produced with at least one boson significantly off-shell. Gamma(H to V V ) is approximately proportional to the product of the Higgs boson coupling and the vector boson width. Gamma Z is well known, but Gamma W gives an uncertainty on Gamma(H to W W ) which is not negligible. The ratio of branching ratios, BR(H to W W )/BR(H to ZZ) measured by a combination of ATLAS and CMS at LHC is used herein to extract a width for the W boson of Gamma W = 1.8+0.4-0.3 GeV by assuming Standard Model couplings of the Higgs bosons. This dependence of the branching ratio on Gamma W is not discussed in most Higgs boson coupling analyses.