Jack Steinberger Biography

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World of Physics on Jack Steinberger

Jack Steinberger is an experimentalist in high-energy physics who discovered a new type of neutrino with the physicists Leon Max Lederman and Melvin Schwartz . In a groundbreaking experiment, the three scientists were able to create the first laboratory-made beam of neutrinos. Their discovery led to the development of the so-called "standard theory" of matter. In recognition of these contributions, Steinberger and his co-investigators were awarded the 1988 Nobel Prize in physics.

Steinberger was born on May 25, 1921, in Bad Kissingen, Germany. His father was Ludwig Lazarus Steinberger, a cantor and leader of the local Jewish community, and his mother was Berta May Steinberger. Jack Steinberger and his brother left Germany in 1934 and immigrated to Chicago, Illinois. There, they lived with the family of Barnard Faroll, a grain broker. Later, Faroll was instrumental in bringing the rest of Steinberger's family to the United States.

Steinberger studied chemical engineering at the Illinois Institute of Technology, but left to enlist in the U.S. army following the attack on Pearl Harbor. The army sent him to the Radiation Laboratory at the Massachusetts Institute of Technology, where he made radar bomb sights and studied physics. After the war, he enrolled at the University of Chicago, earning a bachelor of science degree in 1942, and a doctorate in physics in 1948. During his doctoral studies at Chicago, Steinberger had studied muons (semi-stable electrical particles) and showed that, when they decay, they yield two neutrons (nuclear particles with the mass of protons but not the charge) and an electron (a negatively charged atomic particle). He proposed at the time that muons could be broken down into muon-neutrinos and electron-neutrinos. (The neutrino is an elusive electrically uncharged basic particle of matter that lacks mass). The neutrino was important because Steinberger and other nuclear physicists believed neutrinos could be harnessed to study the weak nuclear force, which is responsible for certain types of radioactivity. The weak force, like electromagnetism, is one of the fundamental interactions between elementary particles.

Creates Neutrino Beam

Steinberger's professional career began at the University of California at Berkeley, with his appointment as professor of physics in 1949. He remained there for a year, and then moved on to Columbia University, also as a professor of physics. It was during a coffee break at the Pupin Physics Building of Columbia University that Melvin Schwartz, then Steinberger's graduate student, broached the idea to Leon Max Lederman and Steinberger of making beams of high-energy neutrinos for use in research. They decided to use the Brookhaven accelerator in Upton, Long Island, New York, to make the beam. They set up the accelerator to produce masses of protons at 15 billion electron volts and shoot them at a beryllium metal target. The protons (elementary positively charged particles) smashed the beryllium atomic nuclei into their component protons and neutrons. The impact also created pions, elusive short-lived particles that decay into muons and neutrinos. Seeking to filter out the neutrinos, the researchers constructed a 40 ft (12 m) barrier of steel built from the scrap of the battleship Missouri. The massive obstacle filtered out all the particles but the neutrinos, creating the first laboratory made beam of high-intensity neutrinos.

Until then, scientists had only been aware of the existence of neutrinos produced by the type of radioactive decay that also creates an electron. But the neutrinos that came out of the steel filter were accompanied by muons. These were muon-neutrinos. This finding led to the development of the "standard model theory," which posits the existence of three generations of matter: a first generation consisting of seven electrons, electron neutrinos and the up and the down quarks (hypothetical particles from which fundamental particles are built); a second generation of matter--that revealed by the experiments carried out by Steinberger and his colleagues--consisting of muons, muon-neutrinos and varieties of quarks called charmed and strange quarks; and a third generation, which physicists are exploring now and which includes tau particles (particles produced when electrons and anti-electrons are smashed together), tau neutrinos, and the top and the bottom quarks. The discovery of the muon-neutrino was a pioneering step in a road that enabled high-energy physicists to use neutrinos in scientific investigations. In astronomy, for instance, neutrino telescopes detect explosions of neutrinos associated with far-off supernoves (stars that blow up with great brilliance).

Steinberger left Columbia University in 1968, moving on to become director, administrator and researcher of the European Center for Nuclear Research in Geneva. He retired from his administrative duties in 1986, but remained as a staff physicist. He has continued to work on experiments in elementary particles and conducts research using the Large Electron-Positron Collider. In 1988 Steinberger received extensive public recognition for his discovery of the muon-neutrino and for a lifetime of contributions to physics. He was awarded not only the Nobel Prize in that year, but also received the National Medal of Science from the United States. Steinberger married Joan Beauregard in 1943. The marriage ended in divorce. In 1961 he married Cynthia Eve Alff. Steinberger is the father of three sons, Joseph, Richard, and John, and a daughter, Julia Karen. Steinberger has become a United States citizen.