From left, Dr. Chen Ning Yang of Princeton University; professor Daniel Bovet of Rome, who received a prize in medicine for his work in the field of pharmacology; Dr. Tsung-Dao Lee, of Columbia University; Sir Alexander Todd of Cambridge University, England, cited for his work in chemistry; and Albert Camus, of France, who received the prize in literature, are shown after receiving their awards in Stockholm, Sweden, Dec. 10, 1957. Associated Press

Tsung-Dao Lee, a physicist who studied science on his own after stumbling upon textbooks in his native China, and then less than two decades later shared a Nobel Prize for upending an assumed law of nature in the subatomic realm, died Aug. 4 at his home in San Francisco. He was 97.

The death was announced in a joint statement by the Tsung-Dao Lee Institute at Shanghai Jiao Tong University and the Beijing-based China Center for Advanced Science and Technology. Lee, who became a U.S. citizen in 1962, was a professor emeritus at Columbia University.

Until the experiments in 1956 spurred by Lee and another physicist born in China – Chen Ning Yang at the Institute for Advanced Study in Princeton, N.J. – understanding of subatomic dynamics was shaped by a tenet known as conservation of parity. That meant that every phenomenon and its “mirror” image – different electric charge, for example – should behave exactly in the same manner.

Since the 1930s, parity was part of the inviolable rules of physics and governed the playbook of quantum physics, the study of subatomic particles. Lee and Yang overturned the principle with studies into intriguing particles, a K meson or kaon, which exists for less than a nanosecond and whose decay includes electrons, neutrinos and photons.

The theory of Lee and Yang was that the “weak” nuclear forces binding a K meson were different from the strong nuclear and electromagnetic forces in other particles. In 1956, they outlined a series of experiments to test the idea. The lab work at Columbia, directed by physicist Chien-Shiung Wu, confirmed their hypothesis: Some particles from the decay of cobalt isotopes spun in a different direction than others. Lee and Yang called it “right-handed” and “left-handed.”

The discovery marked one of the breakthrough moments in 20th-century physics and opened new horizons in disciplines such as high-energy neutrino physics (including the Higgs boson, or “God particle”) and quantum field theory, a conceptual framework that seeks to comprehend the underlying forces of the universe.

The Nobel Prize in physics in 1957 recognized the theoretical contributions of Lee and Yang, described as the first Chinese nationals to receive the prize. The omission of Wu for the experiments was seen by her supporters as a wrongful oversight.

In a 2007 interview to mark the 50th anniversary of their Nobel Prize in physics, Lee credited his atypical path into physics for giving him the perspective to challenge some of the basic premises of the time. (Lee was 31 when the Nobel was presented.)

“Probably because I learned physics in a different way, probably with a different approach so I was questioning what proof do we have,” Lee told Adam Smith, editor of NobelPrize.org. “And so this inquisitiveness, to question that and then, that maybe had to do with my own background.”

Tsung-Dao Lee was born Nov. 24, 1926, in Shanghai in what he called a “family of learning.” His father was a merchant in the chemical industry, and his mother was a homemaker who enjoyed finding books to add to the family library.

When Japanese forces invaded China in 1937, his school studies were disrupted. Then in late 1941, after Japan’s attack on Pearl Harbor drew the United States into World War II, he left Shanghai. He enrolled in 1943 in the National Chekian University (now Zhejiang University in Hangzhou) under a program that allowed an “equal ability” exam in lieu of a high school diploma.

The widening Pacific war forced classes to close again. He still had no introduction to physics. “Zero idea. … But in that period, of course, I tried to learn things in an unorganized way,” he recalled.

He came across some books on science, including a physics textbook on Isaac Newton’s laws, and began to teach himself. He was fascinated by the equations and the ability to test, prove or refute problems in physics. “So I just developed my own system of judgment,” he said in the 2007 interview.

When the war ended, he resumed studies at the National Southwest Associated University, an institution set up during wartime in the 1930s in Kunming. One of his instructors, theoretical physicist Ta-You Wu, nominated him for a government fellowship to study in the United States. He was accepted but still did not have his bachelor’s degree. One institution, the University of Chicago, accepted him into a graduate program in astrophysics.

The physics department was led by Enrico Fermi, a Nobel laureate who had developed the foundations for nuclear fusion and was sometimes called the “father of the atomic bomb.” Fermi took on Tsung-Dao, who became widely known as T.D., as his sole doctorate student in theoretical physics. They had weekly meetings that became an ongoing dialectic.

“He would ask questions and I would have to answer,” Lee recounted. “Everything has to be proved just like that and why. … Later I realized that this was a fantastic effort of Fermi’s part. Personally guiding. To transfer his knowledge to build up the young man’s confidence.”

Lee received his doctorate in 1950 with a dissertation on the hydrogen content of white dwarf stars. He then held various research and lecture positions, including at Yerkes Observatory in Williams Bay, Wisc. In 1953, he became an assistant professor at Columbia and was named full professor at age 29, at the time the youngest person to achieve that title at the university.

Lee later oversaw advanced studies in particle physics including as a director of Brookhaven National Laboratory on Long Island. He also added to research on black holes and cosmic dark matter. In 1957, he received the Albert Einstein Award in Science.

His wife of 46 years, Jeannette Hui-Chun Chin, died in 1996. Survivors include two sons; a brother; a sister; seven grandchildren; and a great-grandson.

In his 2007 interview with the Nobel news site, Lee was asked whether there are more major discoveries ahead in understanding the fundamental laws of physics.

“I would hope it’s still true,” he said, noting that nature never stops presenting a “further puzzle” to solve.