Jack Steinberger, who shared the 1988 Nobel Prize in physics for expanding understanding of the ghostly neutrino, a subatomic particle, died Dec.12 at his home in Geneva. He was 99.

The neutrino’s existence was first proposed in 1931, but finding one proved difficult. It has no electrical charge, travels at nearly the speed of light, and has almost no mass. Not until 1956, when ways to smash atoms and examine the debris were developed, was one detected.

Six years later, Dr. Steinberger joined with two fellow Columbia University physicists, Melvin Schwartz and Leon M. Lederman, to show that two types of neutrinos existed. Just as significant, they devised a method to produce a beam composed of vast numbers of neutrinos at very high energies to study one of the basic forces of nature.

In bestowing the physics prize on the three men, the Nobel awards committee said they had “opened new opportunities for research into the structure and dynamics of matter.”

He was born in Bad Kissingen in Bavaria, Germany. His father was a cantor and religious teacher to the town’s small Jewish community. With the rise of the Nazis, his parents arranged for him to go to the U.S. with the help of the American Jewish charities. He was placed in the home of a wealthy grain broker named Barnett Faroll, who several years later arranged for his parents and brothers to join them in Chicago, rescuing them from the Holocaust.