Measuring the Higgs boson mass in dileptonic W-boson decays at hadron colliders

TL;DR

This paper improves the measurement of the Higgs boson mass in dileptonic W-boson decays at hadron colliders by introducing a better variable that reduces uncertainty, especially at higher masses.

Contribution

The paper identifies and removes an unnecessary approximation in the commonly used variable, leading to a more accurate and potentially more precise Higgs mass measurement method.

Findings

The new variable outperforms the traditional one in all tested scenarios.

It can reduce the fit uncertainty on the Higgs mass by nearly a factor of two.

Performance improvements are especially significant in the high Higgs mass region.

Abstract

It is expected that hadron collider measurements of the Higgs boson mass using the decay h -> W^+W^-, followed by the leptonic decay of each W-boson, will be performed by fitting the shape of a distribution which is sensitive to the Higgs mass. We demonstrate that the variable most commonly used to measure the Higgs mass in this channel is not optimal as it contains an unnecessary and even counter-productive approximation. We remove that approximation, without introducing any cost in complexity, and demonstrate that the new variable is a clear improvement over the old: its performance is never worse, and in some cases (particularly the high Higgs mass region) it might reduce the fit uncertainty on the Higgs mass in that channel by a factor approaching two.