Arthur L. Hughes was an British/Welsh physicist. He worked on the Manhattan Project in St. Louis on the cyclotron and plutonium production and at Los Alamos, NM. He served as an assistant director at Los Alamos.
He studied physics at Liverpool University under Charles Barkla, and later worked at Cavendish Laboratory under J. J. Thomson. He researched cloud chambers, as well as the photoeletric effect. In 1923 he became a professor and chair of the physics department at Washington University in St. Louis, MO.
For more on Hughes's career, please see: Arthur Llewelyn Hughes: Embodiment of the Greatness of Washington University by Robert N. Varney.