According to government regulations of the time, teacher-training college students wanting to move on to universities needed to serve as schoolteachers for one year.

She embarked for the United States with a female friend and chemist from Taicang, Dong Ruo-Fen (董若芬), on the SS President Hoover in August 1936.

[27] Yuan showed her the Radiation Laboratory, where the director was Ernest O. Lawrence, who would soon win the Nobel Prize for Physics in 1939 for his invention of the cyclotron particle accelerator.

[8] Wu was shocked at the sexism in American society when she learned that at Michigan women were not even allowed to use the front entrance, and decided that she would prefer to study at the more liberal Berkeley in California.

Yuan took her to see Raymond T. Birge, the head of the physics department, and he offered Wu a place in the graduate school despite the fact that the academic year had already commenced.

[32][33] Wu missed Chinese cuisine and was not impressed with the food at Berkeley, so she always dined with friends such as Schaeffer at her favorite restaurant, the Tea Garden.

She quickly became his favorite student and the two conducted studies on beta decay, including xenon, which would provide important results in the future of nuclear bombs.

[43][44] The second part of the thesis was about the production of radioactive isotopes of Xe produced by the nuclear fission of uranium with the 37-inch and 60-inch cyclotrons at the Radiation Laboratory.

In spite of Lawrence and Segrè's recommendations, she could not secure a faculty position at a university, so she remained at the Radiation Laboratory as a post-doctoral fellow.

[43] Because of her early achievements, the Oakland Tribune released an issue on her entitled "Outstanding Research in Nuclear Bombardments by a Petite Chinese Lady".

[50] She accepted a job from Princeton University in New Jersey as the first female faculty member in the history of the physics department, where she taught officers of the navy.

[52] The role of the SAM Laboratories, headed by Harold Urey, was to support the Manhattan Project's gaseous diffusion (K-25) program for uranium enrichment.

Wu worked alongside James Rainwater in a group led by William W. Havens Jr.,[53] whose task was to develop radiation detector instrumentation.

John Archibald Wheeler and partner Enrico Fermi suspected that a fission product, Xe-135, with a half-life of 9.4 hours, was the culprit, and might be a neutron poison or absorber.

[56] The paper on the subject was still unpublished, but after Fermi contacted Wu, Segrè visited her dorm room together with Nichols and collected the typewritten draft prepared for the Physical Review.

The suspicions of Fermi and Wheeler came true, Wu's paper unknowingly verified that Xe-135 was indeed the culprit for the B Reactor; it turned out to have an unexpectedly large neutron absorption cross-section.

[60] Like many involved physicists in their later years, Wu later distanced herself from the Manhattan Project due to its destructive outcome and recommended to the Taiwanese president Chiang Kai-shek in 1962 to never build nuclear weapons.

[68] Specifically, the experiment carried out by Wu was the first important confirmation of quantum results relevant to a pair of entangled photons as applicable to the Einstein-Podolsky-Rosen (EPR) paradox.

[74] Due to the civil war and communist takeover led by Mao Zedong, Wu would not return to China until decades later to meet her surviving uncle and younger brother.

[82] Yuan would regularly travel to Brookhaven in Long Island, and on weekends return to the family's Manhattan home near Columbia University where Wu worked as its first female physics professor.

[86] In the year 1949, Wu completely established Fermi's theory and showed how beta decay worked, especially in creating electrons, neutrinos, and positrons.

After careful research, Wu suspected that the problem was that a thick and uneven film of copper(II) sulfate (CuSO4) was being used as a copper-64 beta ray source, which was causing the emitted electrons to lose energy.

Also, Wu needed to apply a constant and uniform magnetic field across the sample of cobalt-60 in order to cause the spin axes of the atomic nuclei to line up in the same direction.

[95] Lee and Yang's theoretical calculations predicted that the beta particles from the cobalt-60 atoms would be emitted asymmetrically and the hypothetical "law of conservation of parity" was invalid.

Wu's critical contribution providing the experimental confirmation proving the CP violation through her rigorous experiment was omitted by the Nobel committee.

[118] Some of her impish students called her the Dragon Lady, after the character of that name in the comic strip Terry and the Pirates due to Wu's strictness and high standards of excellence.

"[124] Their hypothesis was influenced by Wu's demonstration that parity was not conserved, which brought other assumptions that physicists have made about the weak interaction into question.

Using a Van de Graaff accelerator at Columbia with proton, heavy hydrogen, and helium beams, they were able to perform their notable experiment.

[125] Feynman was very happy with the announcement and was so proud of the outcome that he called the CVC theory, together with his diagram and work in quantum electrodynamics, one of his finest scientific accomplishments.

"[145][128] During her retirement, Columbia hosted a celebration "to honor the First Lady of Physics", which garnered a huge reception, and subsequently held a banquet at the Qian Jia Fu restaurant along Broadway.