Lee (Lee), Tszundao( Chinese-American physicist, Nobel Prize in Physics, 1957)
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Biography Lee (Lee), Tszundao
genus. November 25, 1926
Chinese-American physicist Lee Tszundao was born in Shanghai. He was the third of six children of a businessman Lee and Tszinkuna nee Chang Minsk. At the end of 1943. school in Jiangxi Kanchu L. enrolled in the National University of Cheuzyan Kueychu. After the Japanese invasion of China University moved to Kunming, which joined the association evacuees institutions, known as the National South-Western Joint University. L. evacuated along with his university in 1945. For the same reasons, a university student in Kunming was and Chen Ning Yang, who later became a colleague L. Bachelor of Science in Physics A. began in 1946. In the same year, received a scholarship of the Chinese government, he entered the University of Chicago, where he studied under the direction of Enrico Fermi. Ibid held their familiarity with Young, who was also a scholar of Chinese Government. Thesis for doctoral degree, successfully defended L. in 1950, called 'The content of hydrogen in white dwarf stars' ( 'Hydrogen Content of white Dwart Stars').
In 1950, Mr.. L. spent several months as an assistant researcher in astrophysics at Yerksskoy astronomical observatory at Lake Geneva (Wisconsin). The following year he worked as an assistant researcher in physics at the University of California at Berkeley. L. and Young met again in 1951. the Institute for Basic Research in Princeton (New Jersey). In 1953, Mr.. L. became an assistant professor at the Physics Department at Columbia University, and in 1956 at the age of twenty-nine years - full professor. This was the youngest professor in history at Columbia University. From 1960 to 1963. L. served as a professor at the Institute of Fundamental Research, and in 1963. returned to Columbia University.
His friendship with Young, matured for two years he spent them in Princeton. She has continued after the L. returned to Columbia University, and Young remained in the Institute of Fundamental Research. Every week they met for lunch to discuss the scientific issues. One of them dealt with two external types of K-mesons - unstable particles found among the fragments in the bombardment of atomic nuclei high-energy particles. K-mesons decay varied in nature: one K-mesons (called the theta-meson) decays into two pi-meson, and the other K-meson (called tau-meson) - three pi-meson. However, some experimental data indicated that the tau and theta mesons are actually one and the same particle, in particular, they have the same mass and lifetime. The most serious reasons for considering the tau and theta mesons the various particles was the law of parity conservation, coming from one of the most fundamental symmetry. Above all, parity conservation means that the interaction of particles and the mirror image of such interactions satisfy the same physical laws and are indistinguishable from each other. Nature does not favor either the left or right, and therefore we expect that the outcome of any experiment will not be removed. Particles or energy states have a definite parity and are called even (+1) or odd (-1). The law of conservation of parity states that the parity of the decaying particle is the product of parities of particles on which it falls, and the total parity remains unchanged. Since the parity of the pi-meson is equal to -1, the parity of the system of two pi-meson is equal to (-1) бT (-1) = +1. Consequently, the theta-meson decays into two pi-meson, should have parity equal to +1, and the tau-meson decays into three pi-meson - parity, equal to (-1) бT (-1) бT (-1 ) = 1. Thus, conservation of parity requires that the theta-and tau-mesons were different particles. However, it is reliable experimental data that established their similarities, contradicted this conclusion. I L. and Yang began to ponder over this unsolved mystery.
The law of conservation of parity was first clearly formulated in 1925. and has since gained universal acceptance since its use in theoretical and experimental studies proved extremely fruitful. Besides, . intuitively parity conservation was perceived as self-evident: why nature should give a preference to drugimN physics we know four fundamental interactions: strong (between the nucleons - the particles, . which comprise the core), . electromagnetic (between charged particles), . weak (the emission of particles during radioactive decay) and gravitational (between any of the masses),
. In seeking a solution to the problem of theta and tau mesons L. and Young were subjected to analysis of experimental data confirming the conservation of parity. To their surprise, they discovered that there is a lot of data attesting to parity conservation in strong or electromagnetic interaction, but not such that would support the conservation of parity in weak interactions. The gravitational interaction, the weakest of the four, usually negligible in the interactions of subatomic particles. Experimenters have never been subjected to direct experimental verification of parity conservation in weak interactions, probably due to the fact that implied the belief in it. In the dissolution of theta and tau mesons play a major role is the weak interaction.
L. and Young in the first place were theorists, but they suggested several experiments intended to give a final answer to the question of the symmetry of right and left in the weak interactions. After six months of hard training is one of those experiments was carried out in 1956 ... 1957. employee of Columbia University By Tszinsyan and other physicists at the National Bureau of Standards United States at Stanford. Radioactive cobalt, . turns into the decay of nickel and emitting energy difference in the form of beta radiation (electrons) and neutrinos (particles with zero mass and zero charge), . was placed inside the coil of an electromagnet and cooled to a temperature, . close to absolute zero, . that minimizes the influence of thermal effects,
. Because the atoms and their nuclei behave in some respects like tiny magnets, most of the cobalt atoms formed a strong parallel magnetic field in the coil, the direction of which was the reference. Beta-decay (emission of electrons) - the result of the weak interaction. If parity is conserved in the decay of cobalt, in the directions north and south magnetic poles of the source would have to emit the same number of electrons. By convincing evidence is that from the south magnetic pole flies more electrons than with the northern. Thus, the parity in weak interactions is not saved. The outcome of the experiment was a surprise even for L. and Yang, although they expressed daring hypothesis.
Soon it was confirmed in other experiments performed at Columbia University, Richard L. Garwin, Leon Ledermanom and Marcel Veynrichem. These experimenters used the decay of pi mesons in the mu-mesons with subsequent decay of mu-meson into an electron and a neutrino (or antineutrino). They found that the mu-mesons and electrons fly up and down is not symmetrical, as expected, if the parity is conserved. Subsequent experiments conducted in different laboratories, have shown that parity is not conserved and the decay of other particles.
. The fall lasted long enough the law of conservation of parity easier solution to the puzzle of tau and theta mesons: the collapse of one and the same particle can occur on two different routes
. All this has opened new horizons in research and engendered hope for progress towards the target even Albert Einstein - to build a unified theory encompassing all four fundamental interactions.
L. and to Yang was awarded the Nobel Prize in Physics 1957. 'for an insightful study of the so-called conservation laws, which led to important discoveries in physics of elementary particles'. At the award ceremony O.B. Klein of the Royal Swedish Academy of Sciences said: 'Consistency and fairness of mind enabled you to cut the mysterious dead knot in elementary particle physics, . where now, . thanks to your brilliant achievements, . experimental and theoretical works are a continuous flow '.,
. His research interests L
. versatile. He worked successfully in such different fields of physics, field theory, statistical mechanics (the science of the atomic origins of thermal phenomena), hydrodynamics, turbulence theory and astrophysics.
In 1950, Mr.. L. married Chin Yuychzhan (Jeannette), they have two sons. Colleagues speak of L. as a modest, reserved man. Sam L. considers that his main occupation is to contemplate. In his leisure hours he reads novels and enigmatic stories and listening to music. In 1963, Mr.. L. became a citizen of the United States of America.
In 1957. L. won the Albert Einstein Yeshiva University. In 1958, Mr.. Princeton University elected him an honorary doctor. He is a member of the National Academy of Sciences of the USA and the American Physical Society