In 2012, the discovery of the Higgs boson marked the completion of the standard model of elementary particles, raising questions about the universe’s structure. Mysteries surrounding dark matter and the imbalance between matter and antimatter persist as significant scientific puzzles. Against this backdrop, recent findings by the ATLAS collaboration at the Large Hadron Collider take on particular importance.
The latest research from scientists focuses on measuring the “width” of the W-boson – a parameter that indicates its lifetime and decay characteristics. According to the Standard model, the precise width of the W-boson can be predicted, and any significant deviation from that value could suggest the existence of unexplained phenomena.
The W-boson is an elementary particle responsible for the weak force interaction, governing radioactive decay processes like beta decay. These particles can be positively charged (W⁺) or negatively charged (W⁻) and have a substantial mass, influencing the range of weak interaction. The W-boson’s discovery in 1983 at CERN validated the standard model of particle physics.
Previous measurements at CERN and the Fermilab collider indicated a width value of 2085 ± 42 million electron-volts (MEV), consistent with the standard model’s prediction of 2088 ± 1 MEV. However, recent measurements at the LHC revealed a value of 2202 ± 47 MEV, establishing the most precise measurement from a single experiment. While slightly higher than predicted, this value falls within 2.5 standard deviations, aligning with the standard model.
To achieve this level of accuracy, researchers closely analyzed the particle decay process of the W-boson into an electron or muon and a corresponding neutrino, which registers as missing energy in collisions. Calibration of the Atlas detector’s response to these particles, along with accounting for background processes, was crucial for the study.
The study also updated the mass value of the W-boson to 80367 ± 16 MEV, improving upon previous Atlas results. Utilizing proton structure data from