Recent Results on the Higgs Boson Properties in the $H\to ZZ \to 4\ell$ decay channel at CMS

TL;DR

This paper reports precise measurements of the Higgs boson properties in the $H o ZZ o 4 ext{l}$ decay channel using CMS data, including mass, width constraints, and spin-parity analysis, with no additional Higgs-like signals found.

Contribution

It provides the most precise Higgs mass measurement, the first experimental constraint on its total width, and confirms the scalar nature of the boson with extensive data analysis.

Findings

Higgs boson mass measured with high precision

Upper limit set on Higgs total width at 33 MeV

Scalar hypothesis consistent with observed data

Abstract

The latest results on the measurement of the properties of the new boson with mass around 125 GeV are reported. The analysis uses pp collision data recorded by the CMS detector at the LHC, corresponding to integrated luminosities of 5.1 $fb^{-1}$ at $\sqrt{s}$ = 7 TeV and 19.6 $fb^{-1}$ at $\sqrt{s}$ = 8 TeV. The boson is observed in the $H \to ZZ \to 4\ell$ channel ($\ell = e, \mu$) and its mass is measured, giving the most precise result ever achieved. Moreover, the first experimental constraint on Higgs total width using $H \to ZZ \to 4\ell$ events is presented, setting an upper limit of 33 MeV at 95\% confidence level (42 MeV expected). The spin-parity of the boson is studied and the pure scalar hypothesis is found to be consistent with the observation, when compared to the other spin-parity hypotheses. No other significant Standard Model Higgs-like excess is found in the search and upper limits at 95\% condence level exclude the range 129.5 -832.0 GeV.