Mary K. Gaillard

Mary Katharine Gaillard (née Ralph; April 1, 1939 – May 23, 2025) was an American theoretical physicist, known for her work in particle physics. She was a professor of the graduate school at the University of California, Berkeley, a member of the Berkeley Center for Theoretical Physics, and visiting scientist at the Lawrence Berkeley National Laboratory. She was Berkeley's first tenured female physicist.

Gaillard's influential contributions included the prediction of the mass of the charm quark prior to its discovery (with Benjamin W. Lee); the prediction of 3-jet events (with John Ellis and Graham Ross); and the prediction of b-quark mass (with M.S. Chanowitz and Ellis). Gaillard's autobiography is A Singularly Unfeminine Profession, published in 2015 by World Scientific.