(Merriman, 1923 - Princeton, 2015) American physicist whose experiments, carried out with James W. Cronin and other collaborators, demonstrated that certain symmetry laws considered fundamental until 1964 were not verified in some processes in the subatomic world. Due to the profound implications of this discovery, he received in 1980, along with James W. Cronin, the Nobel Prize in Physics.
Val Fitch studied the decay of so-called strange particles, and especially K-mesons, until his interest turned to neutral K-mesons. Throughout the 1960s, in collaboration with Cronin and other scientists, he carried out a series of experiments showing that these subatomic particles sometimes decay through processes that violate CP symmetry, that is, processes to which after applying the symmetry operations (spatial inversion plus charge conjugation) other processes are obtained that cannot happen. This symmetry breaking implied a violation of temporal symmetry, that is, it implied that time is not always reversible on a subatomic scale, as had been assumed to date.
After completing his secondary education in public schools in Nebraska, Val Logsdon Fitch was recruited by the United States Army during World War II and assigned to the Los Alamos laboratory in New Mexico to work on the Manhattan Project, which influenced fundamentally in their education. During the three years he worked there, he learned experimental laboratory techniques and had the opportunity to meet university professors and leading researchers in the field of physics such as Enrico Fermi, Niels Bohr, James Chadwick, and Isidor Isaac Rabi, among others.
At the end of the war, his superior at Los Alamos offered him a position at Cornell University, but at the time Fitch had not yet graduated. Instead of Cornell, he went to McGill University for his degree and later to Columbia, where he received his Ph.D. under Jim Rainwater. After doing his doctoral thesis at Columbia University on the spectrum of muon atoms, he accepted a position at Princeton University and began to study K mesons. The result of this research was the aforementioned discovery, together with James W. Cronin , that on certain occasions the neutral K mesons did not respect CP symmetry, a symmetry which, after the discovery in 1956 of parity symmetry violation by Tsung-Dao Lee and Chen Ning Yang, was considered a fundamental law of physics.