Maurice Goldhaber, one of the pioneers of modern physics whose experiments helped create the current understanding of how the world works, died May 11 at his home on Long Island, N.Y., after a short illness. He had celebrated his 100th birthday less than a month earlier.
Goldhaber was "one of the world's most distinguished nuclear and particle physicists," the U.S. government said in 1998 when it presented him the prestigious Enrico Fermi Award. His innovative and thought-provoking experiments provided much of the foundation for the standard model of physics that now paints our view of the universe, and his leadership and vision as head of the Brookhaven National Laboratory during the 1960s led to three Nobel Prizes in Physics for the Long Island institution.
He was also the head of a family of physicists that made fundamental contributions to the field. His brother Gerson, who died last year, played a key role in the discovery of the antiproton, the charm quark and the psi particle. Maurice's wife, Gertrude Scharff Goldhaber, worked with him on some of his key discoveries and is credited with the discovery that spontaneous fission leads to the emission of neutrons.
Their son Alfred Scharff Goldhaber and grandson David Goldhaber-Gordon are distinguished physicists in their own right.
One of Goldhaber's most important contributions came during the 1950s and involved neutrinos, those insubstantial, nearly invisible particles that can pass through dense matter with virtually no interactions — a phenomenon that makes them extremely difficult to detect and measure.
One of the fundamental rules of physics up until then was the symmetry principle, which held that elementary particles, including the neutrino, are equally likely to spin in either direction, either clockwise or counterclockwise.
In an elegant tabletop experiment conducted at Brookhaven over a period of four years, Goldhaber, L. Grodzins and A.W. Sunyar demonstrated that the neutrino always spins in only one direction, counterclockwise. This discovery led to the overthrow of the idea of parity conservation in weak interactions and to a new view of the nature of fundamental particles.
Maurice Goldhaber was born in Lemberg, Austria, on April 18, 1911. He enrolled in the University of Berlin but moved to England in the early 1930s because of the rise of the Nazi party. As a graduate student at Cambridge University, he approached physicist James Chadwick, who had recently discovered the neutron, with an idea about how to measure the particle's mass.
At the time, researchers believed that the neutron was composed of a proton and an electron. Goldhaber proposed that the pair measure its mass by using radiation to dissociate the recently discovered deuteron, which is composed of a proton and a neutron. Chadwick was enthusiastic, and they made the first accurate measurement of the neutron's mass, proving that it was a new elementary particle and not a composite of the proton and electron.
Goldhaber and Chadwick were also the first to show that some light nuclei break up when bombarded by so-called slow neutrons — neutrons with low kinetic energy. Bombarding lithium-6, for example, produces hydrogen-3 (tritium), which decays into helium-3. Bombarding nitrogen-14 produces carbon-14. Those reactions are still widely used to produce tritium and carbon-14 for scientific experiments.
Goldhaber also demonstrated that beryllium could be a useful moderator for neutrons, reducing their kinetic energy — a principle used in nuclear reactors.
In 1938, Goldhaber immigrated to the United States, taking a position at the University of Illinois. He became a naturalized citizen in 1944.
Working with his wife at the university, he demonstrated that the beta-rays emitted during radioactive decay are identical to electrons.
Illinois had strict anti-nepotism rules, so Gertrude Goldhaber could not be hired onto the faculty. In 1950, the couple therefore moved to Brookhaven, which would hire both. He formally retired from Brookhaven in 1985 but continued performing research almost until the time of his death.
Physicist Martin Blume, who was then editor of the journals published by the American Physical Society, recalled driving Goldhaber to Brookhaven every morning from about 2000 until 2008. "He had an idea a minute," Blume said, noting that he sometimes had to take desperate measures to keep Goldhaber quiet so he could concentrate on driving.
Among physicists, Goldhaber is well known for losing a bet. At a dinner party in 1954 at the home of theoretical physicist Hartland Snyder, Goldhaber got into an animated argument with his host, denying the existence of the antiproton. Snyder said, "I bet you $500 that the antiproton exists." Goldhaber recalled, "Without thinking, I said, 'OK.' "
The next year, a team that included Gerson Goldhaber proved the existence of the particle. Some experts said they finally accepted the existence of the particle because Maurice paid up.
In addition to the Fermi Award, Goldhaber received the National Medal of Science in 1985, the Wolf Prize in 1991 and the J. Robert Oppenheimer Memorial Prize in 1992.
Gertrude Goldhaber died in 1998. In addition to his son Alfred, Goldhaber is survived by another son, Michael; two grandchildren; and four great-grandchildren.