(AGENPARL) – sab 22 luglio 2023 MEDIA INFORMATION / INFORMATION PRESSE
[ATLAS-Higgs_decay_2_photons.png]
Candidate Higgs boson decays into two photons in the ATLAS experiment. (Image: CERN)
ATLAS sets record precision on Higgs boson’s mass
New result from the ATLAS experiment at CERN reaches the unprecedented precision of 0.09%
The new measurement in the diphoton channel, which combines analyses of the full ATLAS data sets from Runs 1 and 2 of the LHC, resulted in a mass of 125.22 billion electronvolts (GeV) with an uncertainty of only 0.14 GeV. With a precision of 0.11%, this diphoton-channel result is the most precise measurement to date of the Higgs boson’s mass from a single decay channel.
Compared to the previous ATLAS measurement in this channel, the new result benefits both from the full ATLAS Run 2 data set, which reduced the statistical uncertainty by a factor of two, and from dramatic improvements to the calibration of photon energy measurements, which decreased the systematic uncertainty by almost a factor of four to 0.09 GeV.
“The advanced and rigorous calibration techniques used in this analysis were critical for pushing the precision to such an unprecedented level,” says Stefano Manzoni, convener of the ATLAS electron–photon calibration subgroup. “Their development took several years and required a deep understanding of the ATLAS detector. They will also greatly benefit future analyses.”
When the ATLAS researchers combined this new mass measurement in the diphoton channel with the earlier mass measurement in the four-lepton channel, they obtained a Higgs boson mass of 125.11 GeV with an uncertainty of 0.11 GeV. With a precision of 0.09%, this is the most precise measurement yet of this fundamental parameter.
“This very precise measurement is the result of the relentless investment of the ATLAS collaboration in improving the understanding of our data,” says ATLAS spokesperson Andreas Hoecker. “Powerful reconstruction algorithms paired with precise calibrations are the determining ingredients of precision measurements. The new measurement of the Higgs boson’s mass adds to the increasingly detailed mapping of this critical new sector of particle physics.”
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