CMS Pins Higgs Boson Mass to 0.07% Precision
The most precise single-experiment Higgs mass measurement to date is a research result, and combining it with ATLAS data could refine the value further.
Updated on Nov. 2, 2026 in Physics
CMS, one of the two general-purpose detectors at CERN's Large Hadron Collider, has measured the Higgs boson mass at 125.065 GeV with an uncertainty of 88 MeV, the most precise single-experiment Higgs mass measurement to date. The result is a research-stage measurement combining two decay channels, not a practical technology.
Why it matters
The Higgs boson mass is a free parameter of the Standard Model, so it has to be pinned down experimentally rather than derived from theory. Sharpening that value narrows the constraints on the model and sets a baseline for future precision studies of the particle's properties.
The measurement reached a 0.07% precision, with an 88 MeV uncertainty on the 125.065 GeV mass. It combines data from the H → γγ and H → ZZ → 4l decay channels across collision energies of 7, 8 and 13 TeV.
The players
CMS (Compact Muon Solenoid) collaboration
A large international particle-physics experiment at CERN's Large Hadron Collider that built one of the two general-purpose detectors used to discover the Higgs boson in 2012.
CERN
The European Organization for Nuclear Research, which operates the Large Hadron Collider and publishes the CMS and ATLAS results from its Geneva campus.
ATLAS collaboration
The other general-purpose experiment at the Large Hadron Collider, whose independent Higgs measurements are the planned partner for a combined mass value.
The details
The Higgs boson is a short-lived particle that decays almost immediately into lighter particles, so physicists infer its mass from those decay products. CMS combined two decay channels: one where the Higgs splits into two photons, and one where it splits into two Z bosons that each decay into a pair of leptons, such as electrons or muons. Producing a precise mass required detector calibration, detailed modelling of the collision processes, and a careful accounting of every source of uncertainty.
Timeline
Collision data from proton-proton runs at 7, 8 and 13 TeV were used in the combined measurement.
The Tech Race
Like the 2012 discovery, this result comes from the CMS and ATLAS pair at the Large Hadron Collider, the two experiments that have led Higgs research. Combining their independent measurements is the stated next step toward an even more precise reference value.
This is fundamental research with no direct consumer application or availability timeline. Its near-term effect is on the physics community, which will use the refined mass value in theoretical and experimental studies.
The takeaway
Watch for the combined CMS and ATLAS Higgs mass value, which the stub identifies as the next step toward a more precise reference figure. Any update to the 125.065 GeV value will show whether the two experiments agree at this level of precision.
Further reading
For background on the particle at the center of this measurement, see recent work in Physics.
Source note: This article includes information reported by Cms.
