News Physics The W boson might not be heavier than expected after all The particle’s mass is an important test of the standard model of particle physics A fresh analysis of W boson measurements from the ATLAS experiment (pictured) at CERN’s Large Hadron Collider is in close agreement with theory and at odds with a heavy W boson mass announced last year. Maximilien Brice/CERN Share this:EmailFacebookTwitterPinterestPocketRedditPrint By James R. Riordon April 3, 2023 at 9:00 am The battle over the heft of a hard-to-detect particle is heating up.