Skip to content
Fellows Directory

Francis Farley

Francis Farley

Professor Francis Farley FRS


Elected: 1972


Francis Farley measured with great accuracy the anomalous magnetic moment of the muon, which led to a marked extension toward short distances and high-momentum transfers of the verified range of validity of quantum electrodynamics. For this purpose, he developed ingenious methods for the storage of muons in a magnetic field. He made important contributions also to the accurate determination of other properties of the muon, to the study of cosmic rays, nuclear reactions and cloud formation and to the development of fast counting methods. Francis’ work on the velocity of gamma rays emitted in the decay of pi-to-infinity mesons led to an accurate verification of the second postulate of special relativity for source velocities near the velocity of light while a by-product of his work on the storage of muons has led to the establishment of the relativistic time dilation effect (so-called clock paradox) for accelerated systems.

Professor Francis Farley FRS died on 16 July 2018.

Interest and expertise

Subject groups

  • Astronomy and physics
    • Elementary particle physics
  • Engineering
    • Fluid dynamics
  • Health and human sciences
    • Medical instrumentation


  • Hughes Medal

    For his ultra-precise measurements of the muon magnetic moment, a severe test of quantum electrodynamics and of the nature of the muon.

Was this page useful?
Thank you for your feedback
Thank you for your feedback. Please help us improve this page by taking our short survey.