The W boson is a elementary particle. It's the fourth heaviest particle within the Commonplace Mannequin, and its mass depends on the Brout-Englert-Higgs mechanism.
The W boson mass is likely one of the most attention-grabbing elementary parameters of the Commonplace Mannequin of particle physics, because it permits for model-independent probes for the results of recent physics.
ATLAS captured a pattern of W bosons when the LHC was working at a collision power of seven TeV in 2011. In 2017, ATLAS revealed its first measurement of the W boson mass. With a 19 MeV uncertainty, the W boson mass got here at 80370 MeV.
In a brand new research, besides the latest measurement from the CDF experiment on the Tevatron, a former accelerator at Fermilab, the brand new ATLAS measurement agrees with and is extra correct than all earlier W mass measurements.
The measurement relies on a reanalysis of a pattern of 14 million W boson candidates produced in proton–proton collisions on the Giant Hadron Collider (LHC), CERN’s flagship particle accelerator.
In its newest analysis, ATLAS reanalyzed its pattern of W bosons from 2011 to extend the accuracy of its earlier measurement. The brand new W boson mass, 80360 MeV with a 16 MeV uncertainty, is 10 MeV decrease and 16% extra correct than the earlier ATLAS discovering. The result is in line with the Commonplace Mannequin.
ATLAS spokesperson Andreas Hoecker stated, “To realize this consequence, ATLAS used a sophisticated data-fitting approach to find out the mass, in addition to more moderen, improved variations of what's often known as the parton distribution features of the proton. These features describe the sharing of the proton’s momentum amongst its constituent quarks and gluons. As well as, ATLAS verified the theoretical description of the W boson manufacturing course of utilizing devoted LHC proton–proton runs.”
“Resulting from an undetected neutrino within the particle’s decay, the W mass measurement is among the many most difficult precision measurements carried out at hadron colliders. It requires extraordinarily correct calibration of the measured particle energies and momenta and a cautious evaluation and wonderful management of modeling uncertainties. This up to date consequence from ATLAS supplies a stringent check and confirms the consistency of our theoretical understanding of electroweak interactions.”
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