Val Logsdon Fitch (March 10, 1923 – February 5, 2015) was an Americannuclear physicist who, with co-researcherJames Cronin, was awarded the 1980Nobel Prize in Physics for a 1964 experiment using theAlternating Gradient Synchrotron atBrookhaven National Laboratory that proved that certainsubatomic reactions do not adhere to fundamental symmetry principles. Specifically, they proved, by examining the decay ofK-mesons, that a reaction run in reverse does not retrace the path of the original reaction, which showed that the reactions of subatomic particles are not indifferent to time. Thus the phenomenon ofCP violation was discovered. This demolished the faith that physicists had that natural laws were governed by symmetry.
Val Logsdon Fitch was born on a cattle ranch nearMerriman, Nebraska, on March 10, 1923, the youngest of three children of Fred Fitch, a cattle rancher, and his wife Frances née Logsdon, a school teacher.[1] He had an older brother and sister.[2] The family farm was about 4 square miles (10 km2) in size.[1] The ranch was small; his father specialized in raising breeding stock.[3] Soon after his birth, his father was badly injured in a horse riding accident and could no longer work on his ranch, so the family moved to the nearby town ofGordon, Nebraska, where his father entered the insurance business.[1] Here he attended school,[1] graduating from Gordon High School in 1940 asvaledictorian.[4][5]
Fitch attendedChadron State College for three years, then transferred toNorthwestern University. This was during WWII; his studies were interrupted by being drafted into the US Army in 1943. After completing basic training, he was sent toCarnegie Institute of Technology for training under theArmy Specialized Training Program.[2] Under this program, some 200,000 soldiers attended colleges for intensive courses. Fitch was in the program for less than a year before the manpower requirements of the war became too great, and the Army terminated the program. Most of the soldiers in the ASTP were posted to combat units, but Fitch was one of a hundred or so ASTP soldiers who joined theSpecial Engineer Detachment (SED), which provided much-needed technicians to theManhattan Project.[2][6][7]
His wartime experiences led Fitch to decide to become a physicist.Robert Bacher, the head of the physics division at Los Alamos, offered him a graduate assistantship atCornell University, but first he needed to complete his undergraduate degree. Rather than return to Northwestern or Carnegie Mellon, he elected to enterMcGill University, which Titterton had recommended. Fitch graduated from McGill with a bachelor's degree inelectrical engineering in 1948. On the advice of Jerry Kellogg, who had been a student of Rabi's atColumbia University, and was a division head at the Los Alamos, Fitch decided to pursue his doctoral studies at Columbia. Kellogg wrote him a letter of introduction to Rabi.James Rainwater became his academic supervisor. Rainwater gave him a paper byJohn Wheeler concerningmu-mesic atoms, atoms in which anelectron is replaced by amuon. These had never been observed; they were completely theoretical and there was no evidence that they existed, but it made a good thesis topic.[1][2]
Fitch designed and built an experiment to measure thegamma rays emitted from mu-mesic atoms. As it turned out, this was a good time to search for them. Columbia had recently commissioned acyclotron at theNevis Laboratories that could produce muons;Robert Hofstadter had developed the thallium-activated sodium iodide gamma ray detector; and wartime advances in electronics yielded advances in components such as newphototubes needed to bring it all together. Initially nothing was found, but Rainwater suggested expanding the search beyond the energy range predicted by Wheeler on the basis of the then-accepted size of the radius of theatomic nucleus as around 1.4 × 10−15 m. When this was done, they found what they had been looking for, discovering in the process that the nucleus was closer to 1.2 × 10−15 m.[1][2] He completed hisPhD in 1954, writing his thesis on "Studies of X-rays from mu-mesonic atoms".[8] The thesis was published in thePhysical Review in November 1953.[9]
In 1949, Fitch married Elise Cunningham, a secretary who worked in the laboratory at Columbia. They had two sons. Elise died in 1972, and in 1976 he married Daisy Harper Sharp, thereby acquiring two stepdaughters and a stepson.[4][10] After obtaining his doctorate, Fitch's interest shifted tostrange particles andK mesons. In 1954, he joined the physics faculty atPrinceton University, where he spent the rest of his career. He was the Class of 1909 Professor of Physics from 1969 to 1976, the Cyrus Fogg Brackett Professor of Physics from 1976 to 1982, and theJames S. McDonnell Distinguished University Professor of Physics from 1982 to 1993, when he retired and took up the position of visiting lecturer with the rank of professor for three years before entering emeritus status.[11][12] He was chair of the physics department from 1976 to 1981.[5]
Fitch conducted much of his research at theBrookhaven National Laboratory, where he became acquainted withJames Cronin. The two of them played bridge at nights while they waited for theCosmotron to become available. Cronin had built a new kind of detector, aspark chamber spectrometer, and Fitch realized that it would be perfect for experiments withK mesons (now known as kaons), whichYale University physicistRobert Adair had suggested had interesting properties worth investigating. They could decay into either matter orantimatter. Along with two colleagues, James Christenson andRené Turlay, they set up their experiment on theAlternating Gradient Synchrotron at Brookhaven. They discovered an unexpected result. The decay of neutral K mesons did not respectCP symmetry. K mesons that decayed intopositrons did so faster than those that decayed intoelectrons.[10][13][14] The importance of this result was not immediately appreciated; but as evidence of theBig Bang accumulated,Andrei Sakharov realized in 1967 that it explained why the universe is largely made of matter and not antimatter.[10] Put simply, they had found "the answer to the physicist's 'Why do we exist?'"[15] For this discovery, Fitch and Cronin received the 1980Nobel Prize in Physics.[1]
^abcdDennis Overbye (February 10, 2015)."Val Fitch, Who Discovered Universe to Be Out of Balance, Is Dead at 91".The New York Times. RetrievedFebruary 11, 2015.Val Fitch, who shared the 1980 Nobel Prize in Physics for work that revealed a surprising imbalance in the laws of nature and helped explain why the collision of matter and antimatter has not destroyed everything in the universe, died on Thursday at his home in Princeton, N.J. He was 91. ...
