(1936- ) Chinese/American Experimentalist, Particle Physicist
Samuel C. C. Ting is a leading experimentalist, best known for his pioneering work in particle physics. His discovery of the J/y particle, an excited state of nuclear matter, confirmed the standard quark lepton model of electroweak and nuclear forces. For this work, he shared the 1976 Nobel Prize in physics with burton richter, who had independently made the same discovery.
He was born on January 27, 1936, in Ann Arbor, Michigan, the first of three children of Kuan Hai Ting and Tsun-Ying Wong, who were both foreign graduate students at the University of Michigan. The accident of his premature birth made Samuel an American citizen. Two months later, his family returned to Beijing, China, where his father became a professor of engineering, and his mother a professor of psychology. World War II prevented him from attending school until he was nine, although his home was always filled with his parents’ colleagues, who imbued him with an early desire to be part of academic life. With both parents working, he was raised by his maternal grandmother, a widow who had struggled to educate herself and her daughter during turbulent years in China’s history. Ting writes of his grandmother and mother, “Both of them were daring, original, and determined people, and they have left an indelible impression on me.” After the war, the family moved to Taiwan, where Ting continued his schooling, excelling in mathematics, science, and history.
In quest of a better education, in 1956, Ting returned to Ann Arbor as an undergraduate at his parents’ alma mater. He had heard that American students earned their own way through college and told his parents he would do likewise. Knowing little English, he arrived with $100 in his pocket and an invitation to stay with his father’s former engineering professor. But he managed to obtain scholarships and worked very hard to retain them. Entering as an engineering student, he soon switched his major to physics. Only three years later, in 1959, he received a B.S. in physics and mathematics. He stayed at Michigan for his graduate studies and received a Ph.D. in physics in 1962 for an experimental thesis supervised by Lawrence Jones and the future Nobel laureate Martin Perl.
In 1963, Ting was awarded a Ford Foundation Fellowship to work at the European Center for Nuclear Research (CERN) in Geneva, where he collaborated with Giuseppi Cocconi on experiments using the 28-billion-volt proton synchrotron. Cocconi taught him a great deal about physics and deeply impressed him with his “simple way of viewing a complex problem” and the care with which he conducted experiments.
Ting returned to the United States in the spring of 1965, to spend an exciting year as an instructor at Columbia University, where he had the chance to observe such eminent physicists as leon m. lederman, tsung-dao lee, isidor isaac rabi, and chien-shiung wu. The following year, however, he took leave from Columbia in order to lead an experimental group at the Deutsches Elektronen Synchrotron (DESY) in Hamburg, Germany. His goal was to reproduce an experiment performed that year at the Cambridge Electron Accelerator at Harvard University on electron-positron pair production by photon collision with a nuclear target. (Positrons are the antiparticles of electrons.) The experiment seemed to indicate findings inconsistent with what Ting knew of quantum electrodynamics (QED), which describes the properties of the interaction of matter and electromagnetic radiation. With the new detector they built, Ting’s group confirmed the results of the Harvard group.
This was a turning point in Ting’s career: from then on he would devote himself to the physics of electron or muon pairs, studying the quantum electrodynamic production and decay of new photonlike particles, which decay to electron or muon pairs. He explains, “These types of experiments are characterized by the need for a high-intensity incident flux, for high rejection against a large number of unwanted background events, and at the same time the need for a detector with good mass resolution.” To achieve these conditions, he took his group back to the United States in 1971, to the Brookhaven National Laboratory in Stony-brook, New York.
In the spring of 1972, Ting’s group modified the detector they had designed in Germany, increasing its sensitivity to the specific energy signal of the electron-positron pairs in order to discern its specific signal amid the noise of millions of other particle collisions. The Nobel Prize committee would later liken this feat to being able to “hear a cricket close to a jumbo jet taking off.” With their newly improved detector, Ting’s team bombarded a beryllium target with a proton beam, took measurements, and looked for the signature of the electron-positron pairs. In August 1974, they made a startling discovery: the first of a totally unpredicted new group of extremely heavy long-lived mesons. After rechecking his results, in November of that year, Ting announced his discovery, which he called the J particle (a name based on the symbol for the electromagnetic current).
Just before publishing his findings, Ting attended a conference at Stanford University with scientists working at the Stanford Linear Accelerator Center and made another astounding discovery: The physicist Burton Richter, using a wholly different experimental approach, had found the same particle, which he called the psi particle. Two years later, both men shared the Nobel Prize for their work in detecting what came to be called the J/y particle, determined to be more than twice as heavy as any comparable particle and yet a thousand times more narrow in its energy spectrum (and that, according to the uncertainty principle, meant that it was a long-lived particle).
In 1961, murray gell-mann and yuval ne’eman had devised the eightfold way, a system for classifying the myriad newly discovered elementary particles into eight families of elementary building blocks called quarks, of which there were three types. The unique feature of the newly discovered J/y particle was that it did not belong to any of the families as they were known prior to 1974. Its detection confirmed sheldon lee glashow’s prediction of a fourth quark (i.e., the charmed quark, which was needed in order to make the Gell-Mann SU(3) quark theory of the strong interactions consistent with this observation).
In 1969, Ting was appointed professor of physics at the Massachusetts Institute of Technology (MIT) in Cambridge, where, in 1977, he was selected as the first recipient of the Thomas Dudley Cabot Institute Professorship. In 1985, he married Dr. Susan Marks, with whom he had a son, Christopher, the following year. He also has two daughters, Jeanne and Amy, from a previous marriage.
Ting continues to spend most of his time at CERN, where he heads the L3 Experiment, launched in 1982, involving more than 500 physicists from about 33 universities and institutions throughout the world. Another major current project in which he is involved is the construction of a three-ton detector, called the Alpha Magnetic Spectrometer (AMS), designed to search for the existence of antimatter nuclei among cosmic rays, which will operate in the International Space Station. Since antimatter is expected to be extremely difficult to detect, experimentation in empty space, where “background noise” is considerably less, is essential. In June 1998, a prototype AMS was tested on the Space Shuttle Discovery.
The AMS may also play a role in investigating the mysterious dark matter, which, though estimated to make up the greater part of the universe, has so far eluded detection. The AMS may be sensitive to certain properties of weakly interacting particles that some physicists believe to be the essence of dark matter.
Ting and Richter’s discovery of the J/y particle changed the landscape of particle physics.
By verifying the need for a charmed quark, it opened the door to the further elaboration of the full Standard Model, which contains six quarks: up, down, strange, charm, top, and bottom.
