Universidad Autónoma de Madrid
Department of Theoretical Physics

Departamento de Física Teórica

New precise measurement of the Higgs boson mass presented by the CMS Collaboration

04/04/2017
Figure 1: Invariant mass of the four-lepton system in the mass range  from 70 GeV to 170 GeV.

Figure 1: Invariant mass of the four-lepton system in the mass range from 70 GeV to 170 GeV.

The CMS Collaboration working at the CERN Large Hadron Collider (LHC) has released its latest results on the measurement of the Higgs boson mass.

The results have been presented on March 19th, 2017, at the ``52nd Rencontres de Moriond on Electroweak Interactions'', one of the main international conferences in High Energy Physics.

The measurement is based on the analysis of events with four charged leptons (4mu, 4e, 2e2mu) in the final state using the full data set collected by the CMS experiment in 2016. This corresponds to a total integrated luminosity of 35.9 fb-1 recorded in proton-proton collisions at a center-of-mass energy ofsqrt(s)=13 TeV. The Higgs boson contributes to this sample via its decay to two Z bosons in the process H->ZZ(*)->4l. Despite the very low branching ratio of the Higgs in this decay mode (0.012%), this is currently the most sensitive analysis studying the properties of this new elementary particle. The Higgs boson resonance in the 4-lepton sample can be seen in red in Figure-1, which shows the invariant mass distribution of the four reconstructed leptons.

The Higgs boson mass measured by CMS at 13TeV is

m_H = 125.26 ± 0.20 (stat.) ± 0.08 (syst.)

This is the most precise measurement of the Higgs mass to date, already improving on the mass measurement obtained from the combination of the entire Run-1 data sets of the CMS and ATLAS Collaborations at sqrt(s)=7 TeV and sqrt(s)=8 TeV.

References:

* The CMS Collaboration,
    Measurements of properties of the Higgs boson decaying into four leptons in pp collisions at sqrt(s)=13 TeV,
    CMS Physics Analysis Summary CMS-PAS-HIG-16-041.
    URL: http://cds.cern.ch/record/2256357

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