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CMS Collaboration Reports Most Precise W Boson Mass Measurement

4/9/2026

Summary

Story summary

The CMS Collaboration measured the W boson mass as 80,360.2 ± 9.9 MeV, the most precise result yet.
The result aligns with the Standard Model and confirms earlier predictions, addressing the heavier Fermilab measurement.
The analysis used advanced statistics, extensive Large Hadron Collider data, and machine learning to improve precision.
Ongoing advancements in measurement techniques will further refine understanding of fundamental particles and forces.

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Story summary

The CMS Collaboration measured the W boson mass as 80,360.2 ± 9.9 MeV, the most precise result yet.
The result aligns with the Standard Model and confirms earlier predictions, addressing the heavier Fermilab measurement.
The analysis used advanced statistics, extensive Large Hadron Collider data, and machine learning to improve precision.
Ongoing advancements in measurement techniques will further refine understanding of fundamental particles and forces.