ATLAS experiment provides precise measurement of W boson.

The ATLAS experiment at CERN has reported a new precision measurement of the mass of the W boson, a fundamental particle that carries the charged weak force. The new measurement is based on a reanalysis of a sample of 14 million W boson candidates produced in proton-proton collisions at the Large Hadron Collider. The new ATLAS measurement concurs with, and is more precise than, all previous W mass measurements except one. The result is in agreement with the Standard Model, which is a cornerstone of particle physics.