Published by the MIT News Office at the Massachusetts Institute of Technology, Cambridge, Mass.
Published by the MIT News Office at the Massachusetts Institute of
Technology, Cambridge, Mass.
WEDNESDAY, OCTOBER 24, 1990
By Eugene F. Mallove
MIT News Office
Professors Jerome I. Friedman and Henry W. Kendall of the Department of Physics and the Laboratory for Nuclear Science will share the 1990 Nobel prize for physics with a colleague at the Stanford Linear Accelerator Center, Professor Richard E. Taylor.
The $710,000 award cited the physicists for research at the Stanford accelerator (SLAC) from 1967 through 1973 that revolutionized particle physics.
Their seminal investigation provided the first experimental evidence for subnuclear particles called quarks, the most fundamental constituents yet known of heavy particles such as protons and neutrons. The work ultimately had a major impact in reconstructing some of the high-energy physics that attended the birth of the universe.
Professor Kendall met the press at a news conference at MIT the day of the award, October 17. Professor Friedman was in Fort Worth, Texas, attending a symposium on the Superconducting Supercollider.
Professor Friedman was awakened by a phone call from his wife who told him of the early-morning call to their home from the Swedish Academy of Science. "It was so unbelievable," Friedman said, "I literally thought I was still sleeping and that this was part of my dream."
Professor Kendall, who received his call from the Swedish Academy at 5am, said, "I was overwhelmed. The work cited was done 20 years ago. It came as quite a surprise; it was delightful and unexpected."
Professor Robert J. Birgeneau, head of the Department of Physics, said, "This Nobel is special because these MIT faculty members are two outstanding human beings. They illustrate perfectly that you can be devoted both to intellectual achievement and to social accomplishment through teaching and public service."
President Charles M. Vest, who assumed office only two days earlier, delivered a statement at the news conference. "Professors Friedman and Kendall brought great distinction both to themselves and to MIT. We're very pleased to be able to join today in celebrating their accomplishments and congratulating them on behalf of all their MIT colleagues," he said.
Later that day, after Professor Kendall was warmly recognized at the regularly scheduled faculty meeting, Dr. Vest drew a laugh when he said he was considering as his first "presidential edict" requiring every faculty member to attend faculty meetings at least twice -- "once when they're introduced as new assistant professors and once when they win the Nobel Prize."
Professor Friedman, a faculty member at MIT since 1960, has served on many national scientific advisory committees and was director of the Laboratory for Nuclear Science from 1981-1983 and head of the department until 1988. Professor Friedman was named two years ago the William A. Coolidge Professor of Physics.
Professor Kendall has been an MIT faculty member since 1961. He studied mathematics at Amherst College before coming to MIT, receiving his PhD in physics here in 1955. Professor Kendall is a founding member (1969) of the Union of Concerned Scientists and has been its chairman since 1973. He has been deeply involved with arms control and nuclear-power safety issues.
Professors Friedman, Kendall and Taylor were the key members of the research team that found the first confirming experimental evidence for the quark model, which Murray Gell-Mann (MIT PhD 1951) and George Zweig of Caltech had proposed in 1964. Gell-Mann won the 1969 Nobel prize in physics, in part for his theory of quarks. (Gell-Mann's choice of the the name "quark" was taken from a character's phrase in James Joyce's novel, Finnegan's Wake.)
Many physicists consider these pioneering experiments to be related to the current picture of elementary particle structure in the same way that the classic Rutherford scattering experiments in the first decade of the 20th century were related to the basic model of the atom -- a nucleus plus surrounding electrons.
The other Nobel announced October 17 went to an MIT graduate, Professor Elias James Corey, Jr. of Harvard (MIT SB 1948, PhD 1951), who won the 1990 prize for chemistry for developing new methods to synthesize complex molecules -- some ordinarily found only in nature. The Nobel committee said of his work, "It is probable that no other chemist has developed such a comprehensive and varied assortment of methods which, often showing the simplicity of genius, have become commonplace in the synthesizing laboratory."
The 1990 Nobels bring to 24 the number of Nobel prizes to people who have either been educated or affiliated with MIT. Friedman and Kendall are the 9th and 10th Nobel laureates currently at MIT.
Friedman, 60, Kendall, 63, and Taylor, 60, first met during the 1950s as graduate students and post-doctoral researchers at Stanford's High Energy Physics Lab. When construction of the two-mile-long Stanford Linear Accelerator began in 1962, they teamed with other physicists, including the current SLAC Director Burton Richter (MIT SB 1952, PhD 1956) to build two huge "magnetic spectrometers," which are used to analyze particles emerging from violent collisions.
In the late 1960s, Professors Friedman, Kendall and Taylor executed at the accelerator a famous series of experiments on the scattering of electrons by protons, deuterons (a proton bound to a neutron), and heavier nuclei. Firing a beam of high-energy electrons at targets made of hydrogen or deuterium, the researchers were able to unravel mysteries in the data that characterized how the electrons were scattered.
In 1968, these investigations gave the first clear evidence of a charged, point-like substructure -- quarks -- inside these massive particles. The revelation went completely against the conventional model of the interiors of protons and neutrons as "mushy" regions. It was believed that no point-like substructure would be found within the nucleons -- protons and neutrons.
Physicists at the time were very skeptical about quarks as real particles. Searches had been made in vain for "free" (outside the proton or neutron) quarks, which -- by Gell-Mann's theory -- had to have unheard-of fractional charges, +2/3 or -1/3 (-2/3 and +1/3 for "anti-quarks"). Professor Friedman said, "The idea of quarks as real physical entities was objected to as totally unreasonable at the time. . . .Old physics dies with great difficulty."
As Friedman and Kendall related at a celebratory colloquium last Thursday, the late physics Nobel laureate Richard Feynmann (MIT SB '39) had been talking at the time about a "parton model" to describe dense mass concentrations, "partons," within nucleons, but his work was not widely accepted. As Professor Friedman related, Feynmann showed great interest in the evidence that he, Kendall, and Taylor had shown him privately.
The interpretation of their data not only gave strong support to the quark model, it provided the experimental underpinnings for "quantum chromodynamics," the currently favored theory of strong interactions among particles -- one of the four basic forces of nature.
As Professor Kendall said at the Wednesday press conference, "It was not a sudden event, like Archimedes discovering the law of buoyancy and jumping out of his bathtub shouting, 'Eureka!' ...It wasn't realized at the time how fundamental [the discovery] was."
The research also found tantalizing hints about what else might be locked within the proton and neutron. Eventually confirmed by others were particles called "gluons," which play a role in sticking the quarks together within a nucleon.
The particles with which most laypeople are familiar are protons and neutrons. Each consists of three quarks. The neutron, for example, is composed of two so-called "down" quarks and one "up" quark. The proton consists of two "up" quarks and one "down" quark.
Unlike protons, each of which has a charge of +1, or neutrons, each with charge 0, quarks have electric charge that comes in fractions.Theory suggests that the quarks are permanently bound within the heavier particles and never appear outside. Other heavy particles called mesons also are composed of quarks, but each has two rather than three.
There are thought to be six different kinds (physicists call them "flavors") of quarks in nature, five of which have already been proved to exist. MIT Professor Samuel C.C. Ting shared the 1976 Nobel Prize for physics with Professor Burton Richter of SLAC for uncovering the first evidence -- through the "J/psi" particle -- of the existence of the "charm" quark. The quarks that have been discovered so far are designated "up, down, charm, strange, and bottom." The search goes on for evidence of the sixth, or "top," quark.
High-energy physicists eagerly await future results from the next generation of accelerator, as represented by the 40-trillion electron-volt Superconducting Supercollider (SSC), 54 miles in circumference, now under development in Texas.
"I think that the SSC is the greatest scientific project ever conceived. It is essential to maintaining intellectual vigor in the field. Possibly we may find with the SSC a level of structure lying within quarks themselves," Professor Friedman said.