The precision measurement of the W boson mass and its impact on physics

Abstract

As a mediator of the weak nuclear force, the W boson influences many properties of fundamental particles and their interactions. Understanding the W boson as accurately as possible, including knowing its mass, has been a priority in particle physics for decades. In the past few years, in a succession of increasing-precision measurements by multiple experiments, a significant tension between the measured and predicted mass has been documented by the CDF Collaboration. Furthermore, smaller differences between different measurements exist. Because the W boson mass provides a window on new physics, a comparison between different measurement techniques can inform the path to further investigations. This Perspective article overviews the role of the W boson mass in the Standard Model of Particle Physics and its extensions, compares and contrasts its measurement techniques and discusses prospects and future directions.