Physicists from the CMS (Compact Muon Solenoid) Collaboration at CERN’s Large Hadron Collider (LHC) have substantially improved the precision with which the mass of the top quark — the heaviest known elementary particle – is measured. Their new result (171.77 GeV) estimates the value of the top quark mass with a precision of about 0.22%. The gain comes from new analysis methods and improved procedures to consistently treat uncertainties...
