Maurice Goldhaber, a prominent American physicist whose discovery of the “left-handedness” of an important subatomic particle was only one of his major contributions to the understanding of nature’s deepest secrets, died May 11 at his home on Long Island, N.Y.

He was 100 years old and reportedly had pneumonia.

One of the European-born scientists who fled the Nazis and made their way to the United States, Dr. Goldhaber helped tease out properties of the atomic nucleus and also headed of one of the nation’s foremost federal research institutions, the Brookhaven National Laboratory in Upton, N.Y.

Scientists ascribe to fundamental particles a quality called spin. An appeal to principles of simplicity and symmetry might suggest that particles spin equally often in one direction as the other, but Dr. Goldhaber helped show through ingenious experimentation that this was not so.

In a paper sent to a scientific journal in 1957, he and collaborators announced that “we find that the neutrino is ‘left-handed.’ ” (The reference is to the direction of rotation around the axis of the neutrino, a mysterious fundamental particle.)

The finding helped prompt the world of physics to set aside one model of the basic structure of matter and look at another.

On one occasion, Dr. Goldhaber’s reputation, his skepticism and his willingness to back up his doubts with cash were credited with leading to the discovery of a key subatomic particle.

This was the antiproton, an ingredient of antimatter. Its existence had been predicted by an important theory, but it had not been found.

Dr. Goldhaber “had bet that the antiproton didn’t exist,” University of California physicist Owen Chamberlain once said. Chamberlain described his reaction to the bet in this way: “Maurice Goldhaber is a good physicist. So if someone of the stature of Maurice thought maybe antiprotons didn’t exist, then this was a real spur to showing that they did.”

Chamberlain discovered the elusive particle and won the Nobel Prize.

Maurice Goldhaber was born April 18, 1911, in Lemberg, a city then in Austria. He was pursuing graduate work at the University of Berlin in the early 1930s as the Nazis were taking power.

Deciding that the best way to avoid the Nazis was to leave Germany, Dr. Goldhaber was accepted to work at Cambridge University by famed physicist Ernest Rutherford, who discovered the nucleus of the atom. At Cambridge, Dr. Goldhaber worked with James Chadwick, who discovered the neutron, the particle that causes nuclear fission.

Late in the 1930s, Dr. Goldhaber came to the United States, joining the faculty of the University of Illinois, before going in 1950 to Brookhaven, where he was director of the laboratory from 1961 to 1973. Three Brookhaven scientists won Nobel Prizes while he was in charge.

After retirement, he remained active at the laboratory and once said of himself, “I don’t have time to age.”

His wife, Gertrude Scharff-Goldhaber, also a nuclear scientist and refu­gee from the Nazis, died in 1998.

His brother, Gerson Goldhaber, a prominent American physicist, died last year at 86.

Dr. Goldhaber’s survivors include two sons, two grandchildren and four great grandchildren.

Ten years ago, when Brookhaven held a celebration to mark his 90th birthday, Dr. Goldhaber offered advice to the young: “Listen to your inner voice,” he said, “and do not run with the crowd.”