was a
Japanese
Japanese may refer to:
* Something from or related to Japan, an island country in East Asia
* Japanese language, spoken mainly in Japan
* Japanese people, the ethnic group that identifies with Japan through ancestry or culture
** Japanese diaspor ...
physicist
A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe.
Physicists generally are interested in the root or ultimate cau ...
and
Marxist
Marxism is a left-wing to far-left method of socioeconomic analysis that uses a materialist interpretation of historical development, better known as historical materialism, to understand class relations and social conflict and a dialecti ...
who was internationally known for theoretical work on the subatomic particles.
[Nussbaum, Louis-Frédéric. (2005). "''Sakata Shōichi''" in ; n.b., Louis-Frédéric is pseudonym of Louis-Frédéric Nussbaum, ''see']
Deutsche Nationalbibliothek Authority File
. He proposed the two meson theory, the
Sakata model
In particle physics, the Sakata model of hadrons was a precursor to the quark model. It proposed that the proton, neutron, and Lambda baryon were elementary particles (sometimes referred to as sakatons
), and that all other known hadrons were made ...
(an early precursor to the
quark model
In particle physics, the quark model is a classification scheme for hadrons in terms of their valence quarks—the quarks and antiquarks which give rise to the quantum numbers of the hadrons. The quark model underlies "flavor SU(3)", or the Ei ...
), and the
Pontecorvo–Maki–Nakagawa–Sakata neutrino mixing matrix.
After the end of
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...
, he joined other physicists in campaigning for the peaceful uses of
nuclear power
Nuclear power is the use of nuclear reactions to produce electricity. Nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions. Presently, the vast majority of electricity from nuclear power is produced b ...
.
Life and career
Early life and education
Sakata was born in
Tokyo
Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, with an estimated 37.46 ...
, Japan on January 18, 1911, to a family that held a tradition of public service. He was the eldest of six children of Tatsue Sakata and . At the time of Sakata's birth, Mikita was secretary to Prime Minister
Katsura Tarō
Prince was a Japanese politician and general of the Imperial Japanese Army who served as the Prime Minister of Japan from 1901 to 1906, from 1908 to 1911, and from 1912 to 1913.
Katsura was a distinguished general of the First Sino-Japanes ...
, who became Sakata's godfather. While attending Kōnan Middle School in
Hyōgo Prefecture
is a prefecture of Japan located in the Kansai region of Honshu. Hyōgo Prefecture has a population of 5,469,762 () and has a geographic area of . Hyōgo Prefecture borders Kyoto Prefecture to the east, Osaka Prefecture to the southeast, an ...
in 1924, Sakata was taught by the physicist
Bunsaku Arakatsu
was a Japanese physics professor in the World War II Japanese Atomic Energy Research Program of the Imperial Japanese Navy. Arakatsu was a former student of Albert Einstein.
Career
In 1928, Arakatsu became a professor in Taihoku Imperial Uni ...
. During his time as a student at Kōnan High School from 1926 to 1929, Sakata attended a lecture given by the influential physicist
Jun Ishiwara. Sakata also became closely acquainted with Katō Tadashi, who would later co-translate
Friedrich Engels's 1883 unfinished work ''
Dialectics of Nature
''Dialectics of Nature'' (german: Dialektik der Natur) is an unfinished 1883 work by Friedrich Engels that applies Marxist ideas – particularly those of dialectical materialism – to nature.
History and contents
Engels wrote most ...
'' into Japanese. According to Sakata, ''Dialectics of Nature'' and
Vladimir Lenin's 1909 work ''
Materialism and Empirio-criticism
''Materialism and Empirio-criticism'' ( Russian: ''Материализм и эмпириокритицизм, Materializm i empiriokrititsizm'') is a philosophical work by Vladimir Lenin, published in 1909. It was an obligatory subject of study ...
'' became formative works for his thinking.
Higher education and career
Sakata got in to the
Kyoto Imperial University in 1930. When he was a second year student,
Yoshio Nishina
was a Japanese physicist who was called "the founding father of modern physics research in Japan". He led the efforts of Japan to develop an atomic bomb during World War II.
Early life and career
Nishina was born in Satoshō, Okayama. He rece ...
, a granduncle-in-law of Sakata, gave a lecture on
quantum mechanics
Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, ...
at the Kyoto Imperial University. Sakata became acquainted with
Hideki Yukawa
was a Japanese theoretical physicist and the first Japanese Nobel laureate for his prediction of the pi meson, or pion.
Biography
He was born as Hideki Ogawa in Tokyo and grew up in Kyoto with two older brothers, two older sisters, and two yo ...
and
Shin'ichirō Tomonaga, the first and the second Japanese Nobel laureates, through the lecture. After graduating from the university, Sakata worked with Tomonaga and Nishina at Rikagaku Kenkyusho (
RIKEN) in 1933 and moved to
Osaka Imperial University in 1934 to work with Yukawa. Yukawa published his first paper on the
meson
In particle physics, a meson ( or ) is a type of hadronic subatomic particle composed of an equal number of quarks and antiquarks, usually one of each, bound together by the strong interaction. Because mesons are composed of quark subparticles, ...
theory in 1935 and Sakata closely collaborated with him for the developments of the meson theory. Possible existence of the neutral nuclear force carrier particle
was postulated by them.
[
] Accompanied by Yukawa, Sakata moved to Kyoto Imperial University as a lecturer in 1939.
Sakata and Inoue proposed their two-meson theory in 1942.
[
] At the time, a charged particle discovered in the hard component cosmic rays was misidentified as the Yukawa's meson (
, nuclear force career particle). The misinterpretation led to puzzles in the discovered cosmic ray particle. Sakata and Inoue solved these puzzles by identifying the cosmic ray particle as a daughter charged fermion produced in the decay. A new neutral fermion was also introduced to allow decay into fermions.
We now know that these charged and neutral fermions correspond to the second generation leptons μ and in the modern language. They then discussed the decay of the Yukawa particle,
:
Sakata and Inoue predicted correct spin assignment for the muon, and they also introduced the second neutrino. They treated it as a distinct particle from the beta decay neutrino, and anticipated correctly the three body decay of the muon. The English printing of Sakata-Inoue's two-meson theory paper was delayed until 1946,
[
]
one year before the experimental discovery of π → μν decay.
Sakata moved to
Nagoya Imperial University as a professor in October 1942 and remained there until his death. The name of the university was changed to Nagoya University in October 1947 after the end of the Pacific War (1945). Sakata reorganized his research group in Nagoya to be administrated under the democracy principle after the War.
Sakata stayed at the Niels Bohr Institute from May to October 1954 at the invitation of
N. Bohr and
C. Møller. During his stay, Sakata gave a talk introducing works of young Japanese particle physics researchers, especially emphasizing an empirical relation found by Nakano and Nishijima,
[
][
] which is now known as the
Nakano-Nishijima-Gell-Mann (NNG) rule[
]
among the strongly interacting particles (hadrons).
After Sakata returned to Nagoya, Sakata and his Nagoya group started researches trying to uncover the physics behind the NNG rule. Sakata then proposed his
Sakata Model
In particle physics, the Sakata model of hadrons was a precursor to the quark model. It proposed that the proton, neutron, and Lambda baryon were elementary particles (sometimes referred to as sakatons
), and that all other known hadrons were made ...
[
]
in 1956, which explains the NNG rule by postulating the fundamental building blocks of all strongly interacting particles are the
proton
A proton is a stable subatomic particle, symbol , H+, or 1H+ with a positive electric charge of +1 ''e'' elementary charge. Its mass is slightly less than that of a neutron and 1,836 times the mass of an electron (the proton–electron mass ...
, the
neutron
The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the atomic nucleus, nuclei of atoms. Since protons and ...
and the
lambda baryon
The lambda baryons (Λ) are a family of subatomic hadron particles containing one up quark, one down quark, and a third quark from a higher flavour generation, in a combination where the quantum wave function changes sign upon the flavour of a ...
. The positively charged pion is made out of a proton and an antineutron, in a manner similar to the Fermi-Yang composite Yukawa meson
model,
[
]
while the positively charged kaon is composed of a proton and an anti-lambda, succeeding to explain the NNG rule in the Sakata model. Aside from the integer charges, the proton, neutron, and lambda have similar properties as the
up quark
The up quark or u quark (symbol: u) is the lightest of all quarks, a type of elementary particle, and a significant constituent of matter. It, along with the down quark, forms the neutrons (one up quark, two down quarks) and protons (two up quark ...
,
down quark
The down quark or d quark (symbol: d) is the second-lightest of all quarks, a type of elementary particle, and a major constituent of matter. Together with the up quark, it forms the neutrons (one up quark, two down quarks) and protons (two up ...
, and
strange quark
The strange quark or s quark (from its symbol, s) is the third lightest of all quarks, a type of elementary particle. Strange quarks are found in subatomic particles called hadrons. Examples of hadrons containing strange quarks include kaons ( ...
respectively.
In 1959, Ikeda, Ogawa and Ohnuki
[
][
]
and, independently, Yamaguchi
[
][
]
found out the
U(3) symmetry in the Sakata model. The U(3) symmetry provides a mathematical descriptions of hadrons in the
eightfold way[
]
idea (1961) of Murray Gell-Mann. Sakata's model was superseded by the
quark model
In particle physics, the quark model is a classification scheme for hadrons in terms of their valence quarks—the quarks and antiquarks which give rise to the quantum numbers of the hadrons. The quark model underlies "flavor SU(3)", or the Ei ...
, proposed by Gell-Mann and
George Zweig
George Zweig (; born May 30, 1937) is a Russian-American physicist. He was trained as a particle physicist under Richard Feynman. He introduced, independently of Murray Gell-Mann, the quark model (although he named it "aces"). He later turned his ...
in 1964, which keeps the U(3) symmetry, but made the constituents fractionally charged and rejected the idea that they could be identified with observed particles. Still, within Japan, integer charged quark models parallel to Sakata's were used until the 1970s, and are still used as effective descriptions in certain domains.
Sakata's model was used in
Harry J. Lipkin's book ''"
Lie Group
In mathematics, a Lie group (pronounced ) is a group that is also a differentiable manifold. A manifold is a space that locally resembles Euclidean space, whereas groups define the abstract concept of a binary operation along with the addi ...
s for Pedestrians"'' (1965).
[
]
The Sakata model and its
SU(3)
In mathematics, the special unitary group of degree , denoted , is the Lie group of unitary matrices with determinant 1.
The more general unitary matrices may have complex determinants with absolute value 1, rather than real 1 in the specia ...
symmetry were also explained in the textbook ''"Weak Interaction of Elementary Particles"'',
L.B.Okun (1965).
[
]
In 1959, Gamba, Marshak and Okubo
[
]
found Sakata's baryon triplet (proton, neutron and lambda baryon) bears striking similarity to the lepton triplet (neutrino, electron and muon) in the weak interaction aspects.
In order to explain the physics behind this similarity in the composite model framework, in 1960, Sakata expanded his composite model to include leptons with his Nagoya University associates Maki, Nakagawa, and Ohnuki.
[
]
The expanded model was termed “Nagoya Model”. Shortly thereafter the existence of two kinds of neutrinos was experimentally confirmed. In 1962, Maki, Nakagawa and Sakata,
[
]
and also Katayama, Matumoto, Tanaka and Yamada
[
]
accommodated the two distinct types of neutrino into the composite model framework.
In his 1962 paper with Maki and Nakagawa, they used the Gell-Mann-Levy proposal of modified universality to define the weak mixing angle that later became known as Cabibbo angle; and extended it to the
leptons
In particle physics, a lepton is an elementary particle of half-integer spin (spin ) that does not undergo strong interactions. Two main classes of leptons exist: charged leptons (also known as the electron-like leptons or muons), and neutra ...
, clearly distinguishing neutrino weak and mass eigenstates, thus defining the neutrino flavor mixing angle as well as predicting neutrino flavor oscillations. The neutrino flavor mixing matrix is now named
Maki–Nakagawa–Sakata matrix. The nontrivial neutrino mixing as introduced in the Maki–Nakagawa–Sakata paper is now experimentally confirmed through the
neutrino oscillation experiments.
Influences
The U(3) symmetry found first in the Sakata model gave a guiding principle to construct the quark model of Gell-Mann and Zweig. The two-meson theory of Sakata and Inoue became well-recognized in the world around 1950.
The 2008 physics
Nobel laureates
The Nobel Prizes ( sv, Nobelpriset, no, Nobelprisen) are awarded annually by the Royal Swedish Academy of Sciences, the Swedish Academy, the Karolinska Institutet, and the Norwegian Nobel Committee to individuals and organizations who make ou ...
Yoichiro Nambu
was a Japanese-American physicist and professor at the University of Chicago. Known for his contributions to the field of theoretical physics, he was awarded half of the Nobel Prize in Physics in 2008 for the discovery in 1960 of the mechanism ...
,
Toshihide Maskawa
was a Japanese theoretical physicist known for his work on CP-violation who was awarded one quarter of the 2008 Nobel Prize in Physics "for the discovery of the origin of the broken symmetry which predicts the existence of at least three famil ...
and
Makoto Kobayashi, who received their awards for work on symmetry breaking, all came under his tutelage and influence. The baryonic mixing in the weak current in the Nagoya Model was the inspiration for the later
Cabibbo–Kobayashi–Maskawa matrix
In the Standard Model of particle physics, the Cabibbo–Kobayashi–Maskawa matrix, CKM matrix, quark mixing matrix, or KM matrix is a unitary matrix which contains information on the strength of the flavour-changing weak interaction. Technicall ...
of 1973, which specifies the mismatch of
quantum states
In quantum physics, a quantum state is a mathematical entity that provides a probability distribution for the outcomes of each possible measurement on a system. Knowledge of the quantum state together with the rules for the system's evolution in ...
of quarks, when they propagate freely and when they take part in
weak interactions
In nuclear physics and particle physics, the weak interaction, which is also often called the weak force or weak nuclear force, is one of the four known fundamental interactions, with the others being electromagnetism, the strong interaction, ...
. Physicists however, generally attribute the introduction of a third generation of
quark
A quark () is a type of elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. All commonly ...
s (the "top" and "bottom" quarks) into the
Standard Model
The Standard Model of particle physics is the theory describing three of the four known fundamental forces ( electromagnetic, weak and strong interactions - excluding gravity) in the universe and classifying all known elementary particles. It ...
of the elementary particles to that 1973 paper by Kobayashi and Maskawa.
The neutrino oscillation phenomena, as predicted by Maki, Nakagawa and Sakata, has been experimentally confirmed (2015 Nobel prize in physics).
Kent Staley (2004) describes the historical background to their paper, emphasizing the largely forgotten role of theorists at Nagoya University and the "Nagoya model" they developed. Several of the authors of the Nagoya model embraced the philosophy of
dialectical materialism
Dialectical materialism is a philosophy of science, history, and nature developed in Europe and based on the writings of Karl Marx and Friedrich Engels. Marxist dialectics, as a materialist philosophy, emphasizes the importance of real-world co ...
, and he discusses the role that such metaphysical commitments play in physical theorizing. Both theoretical and experimental developments that generated great interest in Japan, and ultimately stimulated Kobayashi and Maskawa's 1973 work, went almost entirely unnoticed in the U.S. The episode exemplifies both the importance of untestable "themata" in developing new theories, and the difficulties that may arise, when two parts of a research community work in relative isolation from one another.
[Kent W. Staley; ''Lost Origins of the Third Generation of Quarks: Theory, Philosophy'': Pages 210-229 in Physics in Perspective (PIP), Birkhäuser, Basel (2004). ISSN 1422-6944]
Missed out on Nobel Prize
Shoichi Sakata's "Sakata model" inspired
Murray Gell-Mann
Murray Gell-Mann (; September 15, 1929 – May 24, 2019) was an American physicist who received the 1969 Nobel Prize in Physics for his work on the theory of elementary particles. He was the Robert Andrews Millikan Professor of Theoretical ...
and
George Zweig
George Zweig (; born May 30, 1937) is a Russian-American physicist. He was trained as a particle physicist under Richard Feynman. He introduced, independently of Murray Gell-Mann, the quark model (although he named it "aces"). He later turned his ...
's
quark model
In particle physics, the quark model is a classification scheme for hadrons in terms of their valence quarks—the quarks and antiquarks which give rise to the quantum numbers of the hadrons. The quark model underlies "flavor SU(3)", or the Ei ...
, but the 1969 prize was only awarded to Murray Gell-Mann. Afterward,
Ivar Waller
Ivar Waller (11 June 1898 – 12 April 1991) was a Swedish professor of theoretical physics at Uppsala University. He developed the theory of X-ray scattering by lattice vibrations of a crystal, building upon the prior work of Peter Debye. The De ...
, the member of
Nobel Committee for Physics
The Nobel Committee for Physics is the Nobel Committee responsible for proposing laureates for the Nobel Prize for Physics. was sorry that Sakata had not received a prize.
[Robert Marc Friedman, ''The Politics of Excellence: Behind the Nobel Prize in Science.'' New York: Henry Holt & Company (October 2001)]
In September 1970,
Hideki Yukawa
was a Japanese theoretical physicist and the first Japanese Nobel laureate for his prediction of the pi meson, or pion.
Biography
He was born as Hideki Ogawa in Tokyo and grew up in Kyoto with two older brothers, two older sisters, and two yo ...
politely wrote to Waller informing him that Sakata had been ill when the nomination was written; since then, his condition had worsened significantly. Three weeks later, Sakata died. Yukawa informed Waller that a prize to Sakata would have brought him much honor and encouragement. He, then, in the name of leading Japanese particle physicists, asked to know what the Nobel committee thought of Sakata's merits, for that would perhaps bring them consolation.
Honors
*
Asahi Prize
The , established in 1929, is an award presented by the Japanese newspaper ''Asahi Shimbun'' and Asahi Shimbun Foundation to honor individuals and groups that have made outstanding accomplishments in the fields of arts and academics and have greatl ...
1948
*
Imperial Prize of the Japan Academy
The is a prestigious honor conferred to two of the recipients of the Japan Academy Prize.
Overviews
It is awarded in two categories: humanities and natural sciences. The Emperor and Empress visit the awarding ceremony and present a vase to ...
1950
*
Order of the Sacred Treasure
The is a Japanese order, established on 4 January 1888 by Emperor Meiji as the Order of Meiji. Originally awarded in eight classes (from 8th to 1st, in ascending order of importance), since 2003 it has been awarded in six classes, the lowest tw ...
(瑞宝章 ''Zuihōshō'') 1970
References
Further reading
* Nussbaum, Louis-Frédéric and Käthe Roth. (2005)
''Japan encyclopedia.''Cambridge:
Harvard University Press
Harvard University Press (HUP) is a publishing house established on January 13, 1913, as a division of Harvard University, and focused on academic publishing. It is a member of the Association of American University Presses. After the retir ...
.
OCLC 58053128
External links
CP Violation"> CP Violation and Flavour Mixing
{{DEFAULTSORT:Sakata, Shoichi
1970_deaths">1911_births
1970_deaths
Japanese_Marxists.html" ;"title="1970_deaths.html" ;"title="1911 births
1970 deaths">1911 births
1970 deaths
Japanese Marxists">1970_deaths.html" ;"title="1911 births
1970 deaths">1911 births
1970 deaths
Japanese Marxists
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Osaka University faculty
Kyoto University faculty
Nagoya University faculty
Osaka University alumni
Laureates of the Imperial Prize
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