Who discovered the quark?
Strange quark
The first strange particle (a particle containing a strange quark) was discovered in 1947 (kaons), but the existence of the strange quark itself (and that of the up and down quarks) was only postulated in 1964 by Murray Gell-Mann and George Zweig to explain the Eightfold Way classification scheme of hadrons. The first evidence for the existence of quarks came in 1968, in deep inelastic scattering experiments at the Stanford Linear Accelerator Center. These experiments confirmed the existence of up and down quarks, and by extension, strange quarks, as they were required to explain the Eightfold Way.
Luciano Maiani
Luciano Maiani has authored over 100 scientific publications on the theory of elementary particles often with several co-authors. In 1970 he predicted the charmed quark in a paper with Glashow and Iliopoulos which was later discovered at SLAC and Brookhaven in 1974 and led to a Nobel Prize in Physics for the discoverers. Working with Guido Altarelli in 1974 they explained that the observed octet enhancement in weak non-leptonic decays was due to a leading gluon exchange effect in quantum chromodynamics. They later extended this effect to describe the weak non-leptonic decays of charm and bottom quarks as well and also produced a parton model description of heavy flavor weak decays. In 1976 Maiani analyzed the CP violation in the six-quark theory and predicted the very small electric dipole moment of the neutron. In the 1980s he started using the numerical simulation of lattice QCD and this led to the first prediction of the decay constant of pseudoscalar charmed mesons and of B mesons. A proponent of supersymmetry, Maiani once said that the search for it was "primary goal of modern particle physics".
He has not confined his interest to the theoretical side of physics either, with involvement in ALPI, EUROBALL, DAFNE, VIRGO and the LHC.
Top quark
The proposal of Kobayashi and Maskawa heavily relied on the GIM mechanism put forward by Sheldon Lee Glashow, John Iliopoulos and Luciano Maiani, which predicted the existence of the then still unobserved charm quark. When in November 1974 teams at Brookhaven National Laboratory (BNL) and the Stanford Linear Accelerator Center (SLAC) simultaneously announced the discovery of the J/ψ meson, it was soon after identified as a bound state of the missing charm quark with its antiquark. This discovery allowed the GIM mechanism to become part of the Standard Model. With the acceptance of the GIM mechanism, Kobayashi and Maskawa's prediction also gained in credibility. Their case was further strengthened by the discovery of the tau by Martin Lewis Perl's team at SLAC between 1974 and 1978. This announced a third generation of leptons, breaking the new symmetry between leptons and quarks introduced by the GIM mechanism. Restoration of the symmetry implied the existence of a fifth and sixth quark.
Daniel Quare
Daniel Quare (1648 or 1649 – 21 March 1724) was an English clockmaker and instrument maker who Invented a repeating watch movement in 1680 and a portable barometer in 1695.
Ralph A. James
Ralph Arthur James (23 September 1920 in Salt Lake City, Utah – 24 February 1973 in Alamo, California) was a chemist at the University of Chicago who co-discovered the elements curium (1944) and americium (1944–1945). Later he worked at UCLA and at the Lawrence Livermore laboratory in California.
Cobalt
Swedish chemist Georg Brandt (1694–1768) is credited with discovering cobalt circa 1735, showing it to be a previously unknown element, different from bismuth and other traditional metals. Brandt called it a new "semi-metal". He showed that compounds of cobalt metal were the source of the blue color in glass, which previously had been attributed to the bismuth found with cobalt. Cobalt became the first metal to be discovered since the pre-historical period. All other known metals (iron, copper, silver, gold, zinc, mercury, tin, lead and bismuth) had no recorded discoverers.
Pentaquark
A quark is a type of elementary particle that has mass, electric charge, and colour charge, as well as an additional property called flavour, which describes what type of quark it is (up, down, strange, charm, top, or bottom). Due to an effect known as colour confinement, quarks are never seen on their own. Instead, they form composite particles known as hadrons so that their colour charges cancel out. Hadrons made of one quark and one antiquark are known as mesons, while those made of three quarks are known as baryons. These 'regular' hadrons are well documented and characterized; however, there is nothing in theory to prevent quarks from forming 'exotic' hadrons such as tetraquarks with two quarks and two antiquarks, or pentaquarks with four quarks and one antiquark.
History of chemistry
Marie Skłodowska-Curie was a Polish-born French physicist and chemist who is famous for her pioneering research on radioactivity. She and her husband are considered to have laid the cornerstone of the nuclear age with their research on radioactivity. Marie was fascinated with the work of Henri Becquerel, a French physicist who discovered in 1896 that uranium casts off rays similar to the X-rays discovered by Wilhelm Röntgen. Marie Curie began studying uranium in late 1897 and theorized, according to a 1904 article she wrote for Century magazine, "that the emission of rays by the compounds of uranium is a property of the metal itself—that it is an atomic property of the element uranium independent of its chemical or physical state." Curie took Becquerel's work a few steps further, conducting her own experiments on uranium rays. She discovered that the rays remained constant, no matter the condition or form of the uranium. The rays, she theorized, came from the element's atomic structure. This revolutionary idea created the field of atomic physics and the Curies coined the word "radioactivity" to describe the phenomena.
Eightfold way (physics)
In physics, the eightfold way is a theory organizing subatomic hadrons. The name was coined by American physicist Murray Gell-Mann as an allusion to the Noble Eightfold Path of Buddhism. It led to the development of the quark model.
Quakers in Europe
Well-known German Quakers include: Elisabeth Abegg, Annot, John William Gerard de Brahm, Hans Einstein, Carl Hermann, John Theodore Merz, Marcello Pirani, and Gerhart von Schulze-Gavernitz.
Quark
The quark flavors were given their names for several reasons. The up and down quarks are named after the up and down components of isospin, which they carry. Strange quarks were given their name because they were discovered to be components of the strange particles discovered in cosmic rays years before the quark model was proposed; these particles were deemed "strange" because they had unusually long lifetimes. Glashow, who co-proposed charm quark with Bjorken, is quoted as saying, "We called our construct the 'charmed quark', for we were fascinated and pleased by the symmetry it brought to the subnuclear world." The names "bottom" and "top", coined by Harari, were chosen because they are "logical partners for up and down quarks". In the past, bottom and top quarks were sometimes referred to as "beauty" and "truth" respectively, but these names have somewhat fallen out of use. While "truth" never did catch on, accelerator complexes devoted to massive production of bottom quarks are sometimes called "beauty factories".
Paul-Jacques Curie
Paul-Jacques Curie (29 October 1855 – 19 February 1941) was a French physicist and professor of mineralogy at the University of Montpellier. Along with his younger brother, Pierre Curie, he studied pyroelectricity in the 1880s, leading to their discovery of some of the mechanisms behind piezoelectricity.
George Zweig
As pointed out by astrophysicist John Gribbin, Gell-Mann deservedly received the Nobel Prize for physics in 1969, for his overall contributions and discoveries concerning the classification of elementary particles and their interactions; at that time, quark theory had not become fully accepted, and was not specifically mentioned in the official citation of the prize. In later years, when quark theory became established as the standard model of particle physics, the Nobel committee presumably felt they couldn't recognize Zweig as the scientist who first spelled out the theory's implications in detail and suggested that they might be real, without including Gell-Mann again.
Nevertheless, in 1977 Richard Feynman nominated both Gell-Mann and Zweig for the Nobel prize, presumed to be his only
nomination for such.
Whatever the reason, despite Zweig's contributions to a theory central to modern physics, he has not yet been awarded a Nobel prize.
Strangeness production
The diagnosis and the study of the properties of quark–gluon plasma can be undertaken using quarks not present in matter seen around us. The experimental and theoretical work relies on the idea of strangeness enhancement. This was the first observable of quark–gluon plasma proposed in 1980 by Johann Rafelski and Rolf Hagedorn. Unlike the up and down quarks, strange quarks are not brought into the reaction by the colliding nuclei. Therefore, any strange quarks or antiquarks observed in experiments have been "freshly" made from the kinetic energy of colliding nuclei. Conveniently, the mass of strange quarks and antiquarks is equivalent to the temperature or energy at which protons, neutrons and other hadrons dissolve into quarks. This means that the abundance of strange quarks is sensitive to the conditions, structure and dynamics of the deconfined matter phase, and if their number is large it can be assumed that deconfinement conditions were reached.
Charm quark
The existence of a fourth quark had been speculated by a number of authors around 1964 (for instance by James Bjorken and Sheldon Glashow), but its prediction is usually credited to Sheldon Glashow, John Iliopoulos and Luciano Maiani in 1970 (see GIM mechanism). The first charmed particle (a particle containing a charm quark) to be discovered was the J/ψ meson. It was discovered by a team at the Stanford Linear Accelerator Center (SLAC), led by Burton Richter, and one at the Brookhaven National Laboratory (BNL), led by Samuel Ting.
Randolph Quirk
Quirk became so deeply interested in explosives that he started an external degree in chemistry, but his English undergraduate studies were completed from 1945 to 1947 (with the department back in Bloomsbury) and was then invited to take up a research fellowship in Cambridge; however he took up a counter-offer of a junior lectureship at UCL, which he held until 1952. In this period he completed his MA on phonology and his PhD thesis on syntax, and in 1951 became a post-doctoral Commonwealth Fund fellow at Yale University and Michigan State University. Shortly after his return from the US in 1952, he moved to the University of Durham, becoming reader there in 1954, and professor in 1958. He returned to UCL as professor in 1960 and in 1968 succeeded Smith as Quain Professor, a post he held until 1981.
Fundamental interaction
Murray Gell-Mann along with George Zweig first proposed fractionally charged quarks in 1961. Throughout the 1960s, different authors considered theories similar to the modern fundamental theory of quantum chromodynamics (QCD) as simple models for the interactions of quarks. The first to hypothesize the gluons of QCD were Moo-Young Han and Yoichiro Nambu, who introduced the quark color charge and hypothesized that it might be associated with a force-carrying field. At that time, however, it was difficult to see how such a model could permanently confine quarks. Han and Nambu also assigned each quark color an integer electrical charge, so that the quarks were fractionally charged only on average, and they did not expect the quarks in their model to be permanently confined.
QR algorithm
The LR algorithm was developed in the early 1950s by Heinz Rutishauser, who worked at that time as a research assistant of Eduard Stiefel at ETH Zurich. Stiefel suggested that Rutishauer use the sequence of moments "y" "A" "x", "k" = 0, 1, … (where "x" and "y" are arbitrary vectors) to find the eigenvalues of "A". Rutishauer took an algorithm of Alexander Aitken for this task and developed it into the "quotient–difference algorithm" or "qd algorithm". After arranging the computation in a suitable shape, he discovered that the qd algorithm is in fact the iteration "A" = "L""U" (LU decomposition), "A" = "U""L", applied on a tridiagonal matrix, from which the LR algorithm follows.
Keane Wonder Mine
The location was discovered by a miner named Jack Keane. Keane and a partner named Domingo Etcharren had scouted the area, called Chloride Cliffs, and had located a potential silver mine. Etcharren eventually left while Keane stayed behind to scout the area more thoroughly. As Etcharren was leaving he noticed an outcropping of quartz, which can often be found near gold deposits. When Keane investigated further, he discovered gold. Keane named the find "Keane's Wonder" and the two miners quickly sold an option on the claim to a New Yorker named Joseph DeLamar.
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 attention to neurobiology. He has worked as a Research Scientist at Los Alamos National Laboratory and MIT, and in the financial services industry.
Quadratrix of Hippias
The quadratrix is mentioned in the works of Proclus (412–485), Pappus of Alexandria (3rd and 4th centuries) and Iamblichus (c. 240 – c. 325). Proclus names Hippias as the inventor of a curve called quadratrix and describes somewhere else how Hippias has applied the curve on the trisection problem. Pappus only mentions how a curve named quadratrix was used by Dinostratus, Nicomedes and others to square the circle. He neither mentions Hippias nor attributes the invention of the quadratrix to a particular person. Iamblichus just writes in a single line, that a curve called a quadratrix was used by Nicomedes to square the circle.
Quack-monument
The Quack monument was originally founded in 1926 from a legacy of Arnoldus Burchard Adolphus Quack (Nijmegen, 6 April 1842 - Nijmegen, 11 November 1920). Quack was alderman of the municipality of Nijmegen from 1902 to 1919. The monument is named after him and his twin sister Maria (Marie) Christina (Nijmegen, April 6, 1842 - Nijmegen, March 15, 1905). Quack left his legacy to the municipality of Nijmegen under the condition that a fountain, the Marie Adolphron named after his sister, would be erected.
Clock
The piezoelectric properties of crystalline quartz were discovered by Jacques and Pierre Curie in 1880. The first crystal oscillator was invented in 1917 by Alexander M. Nicholson after which, the first quartz crystal oscillator was built by Walter G. Cady in 1921. In 1927 the first quartz clock was built by Warren Marrison and J.W. Horton at Bell Telephone Laboratories in Canada. The following decades saw the development of quartz clocks as precision time measurement devices in laboratory settings—the bulky and delicate counting electronics, built with vacuum tubes, limited their practical use elsewhere. The National Bureau of Standards (now NIST) based the time standard of the United States on quartz clocks from late 1929 until the 1960s, when it changed to atomic clocks. In 1969, Seiko produced the world's first quartz wristwatch, the Astron. Their inherent accuracy and low cost of production resulted in the subsequent proliferation of quartz clocks and watches.
Richard Feynman
The SLAC National Accelerator Laboratory deep inelastic scattering experiments of the late 1960s showed that nucleons (protons and neutrons) contained point-like particles that scattered electrons. It was natural to identify these with quarks, but Feynman's parton model attempted to interpret the experimental data in a way that did not introduce additional hypotheses. For example, the data showed that some 45% of the energy momentum was carried by electrically neutral particles in the nucleon. These electrically neutral particles are now seen to be the gluons that carry the forces between the quarks, and their three-valued color quantum number solves the omega-minus problem. Feynman did not dispute the quark model; for example, when the fifth quark was discovered in 1977, Feynman immediately pointed out to his students that the discovery implied the existence of a sixth quark, which was discovered in the decade after his death.
Quark epoch
In physical cosmology the Quark epoch was the period in the evolution of the early universe when the fundamental interactions of gravitation, electromagnetism, the strong interaction and the weak interaction had taken their present forms, but the temperature of the universe was still too high to allow quarks to bind together to form hadrons. The quark epoch began approximately 10 seconds after the Big Bang, when the preceding electroweak epoch ended as the electroweak interaction separated into the weak interaction and electromagnetism. During the quark epoch the universe was filled with a dense, hot quark–gluon plasma, containing quarks, leptons and their antiparticles. Collisions between particles were too energetic to allow quarks to combine into mesons or baryons. The quark epoch ended when the universe was about 10 seconds old, when the average energy of particle interactions had fallen below the binding energy of hadrons. The following period, when quarks became confined within hadrons, is known as the hadron epoch.
Lawrence H. Knox
Lawrence Howland Knox (September 30, 1906 – 1966) was among the first African Americans to receive a PhD in chemistry, following his brother William Jacob Knox (1904–1995). He worked with Paul Doughty Bartlett on an experiment for testing organic mechanisms in chemistry which involved the use of the molecule bicyclo(2.2.1)heptane, a type of bicyclic molecule. Knox was the grandson of a slave.
Quark Expeditions
ICEBREAKERS
Kazuhiko Nishijima
where "Q" is the electric charge, "I" is the isospin projection, "B" is the baryon number, and "S" is the strangeness quantum number of the particle. This formula was pivotal for the later development of the quark model by Gell-Mann and George Zweig in 1964 (independently of each other).
Chronology of the universe
The quark epoch began approximately 10 seconds after the Big Bang. This was the period in the evolution of the early universe immediately after electroweak symmetry breaking, when the fundamental interactions of gravitation, electromagnetism, the strong interaction and the weak interaction had taken their present forms, but the temperature of the universe was still too high to allow quarks to bind together to form hadrons.
Cabibbo–Kobayashi–Maskawa matrix
When the charm quark was discovered in 1974, it was noticed that the down and strange quark could decay into either the up or charm quark, leading to two sets of equations:
List of particles
Quark models, first proposed in 1964 independently by Murray Gell-Mann and George Zweig (who called quarks "aces"), describe the known hadrons as composed of valence quarks and/or antiquarks, tightly bound by the color force, which is mediated by gluons. A "sea" of virtual quark-antiquark pairs is also present in each hadron.
History of subatomic physics
The interaction of these particles by scattering and decay provided a key to new fundamental quantum theories. Murray Gell-Mann and Yuval Ne'eman brought some order to mesons and baryons, the most numerous classes of particles, by classifying them according to certain qualities. It began with what Gell-Mann referred to as the "Eightfold Way", but proceeding into several different "octets" and "decuplets" which could predict new particles, most famously the , which was detected at Brookhaven National Laboratory in 1964, and which gave rise to the "quark" model of hadron composition. While the quark model at first seemed inadequate to describe strong nuclear forces, allowing the temporary rise of competing theories such as the S-matrix theory, the establishment of quantum chromodynamics in the 1970s finalized a set of fundamental and exchange particles (). It postulated the fundamental strong interaction, experienced by quarks and mediated by gluons. These particles were proposed as a building material for hadrons (see hadronization). This theory is unusual because individual (free) quarks cannot be observed (see color confinement), unlike the situation with composite atoms where electrons and nuclei can be isolated by transferring ionization energy to the atom.
Quark model
Color quantum numbers are the characteristic charges of the strong force, and are completely uninvolved in electroweak interactions. They were discovered as a consequence of the quark model classification, when it was appreciated that the spin "S" =  baryon, the , required three up quarks with parallel spins and vanishing orbital angular momentum. Therefore, it could not have an antisymmetric wave function, (due to the Pauli exclusion principle), unless there were a hidden quantum number. Oscar Greenberg noted this problem in 1964, suggesting that quarks should be para-fermions.
Daniela Bortoletto
Bortoletto moved to Purdue University to pursue a postdoctoral fellowship. In 1994, she received a NSF Career Advancement Award and became the Alfred P. Sloan Research Fellow. While part of the CDF collaboration in 1995, she co-discovered the top quark. Two years later, she won a NSF Faculty Early Career Development Award. In 2004, she gained fellowship of the American Physical Society.
Quadrant (instrument)
During the Middle Ages the knowledge of these instruments spread to Europe. In the 13th century Jewish astronomer Jacob ben Machir ibn Tibbon was crucial in further developing the quadrant. He was a skilled astronomer and wrote several volumes on the topic, including an influential book detailing how to build and use an improved version of the quadrant. The quadrant that he invented came to be known as the “novus quadrans”, or new quadrant. This device was revolutionary because it was the first quadrant to be built that did not involve several moving parts and thus could be much smaller and more portable.
History of chemistry
The element iodine was discovered by French chemist Bernard Courtois in 1811. Courtois gave samples to his friends, Charles Bernard Desormes (1777–1862) and Nicolas Clément (1779–1841), to continue research. He also gave some of the substance to Gay-Lussac and to physicist André-Marie Ampère. On December 6, 1813, Gay-Lussac announced that the new substance was either an element or a compound of oxygen. It was Gay-Lussac who suggested the name ""iode"", from the Greek word ιώδες (iodes) for violet (because of the color of iodine vapor). Ampère had given some of his sample to Humphry Davy. Davy did some experiments on the substance and noted its similarity to chlorine. Davy sent a letter dated December 10 to the Royal Society of London stating that he had identified a new element. Arguments erupted between Davy and Gay-Lussac over who identified iodine first, but both scientists acknowledged Courtois as the first to isolate the element.
Quark (dairy product)
The word "Quark" (Late Middle High German: "quarc", "twarc", "zwarg"; Lower Saxon: "dwarg"), with usage in German documented since the 14th century, is thought to derive from a West Slavic equivalent, such as Lower Sorbian "twarog", Upper Sorbian "twaroh", Polish "twaróg", Czech and Slovak "tvaroh", and is also cognate with Russian "tvorog" (), Bulgarian "tvarog" () and Belarusian: "tvarog" (тварог).
Murray Gell-Mann
In 1972 he and Harald Fritzsch introduced the conserved quantum number "color charge", and later, together with Heinrich Leutwyler, they coined the term quantum chromodynamics (QCD) as the gauge theory of the strong interaction. The quark model is a part of QCD, and it has been robust enough to accommodate in a natural fashion the discovery of new "flavors" of quarks, which superseded the eightfold way scheme.
Sheldon Lee Glashow
In collaboration with James Bjorken, Glashow was the first to predict a fourth quark, the charm quark, in 1964. This was at a time when 4 leptons had been discovered but only 3 quarks proposed. The development of their work in 1970, the GIM mechanism showed that the two quark pairs: (d.s), (u,c), would largely cancel out flavor changing neutral currents, which had been observed experimentally at far lower levels than theoretically predicted on the basis of 3 quarks only. The prediction of the charm quark also removed a technical disaster for any quantum field theory with unequal numbers of quarks and leptons — an anomaly — where classical field theory symmetries fail to carry over into the quantum theory.
History of science and technology in Japan
The bottom quark is a product in almost all top quark decays, and is a frequent decay product for the Higgs boson. The bottom quark was theorized in 1973 by physicists Makoto Kobayashi and Toshihide Maskawa to explain CP violation. Toshihide Maskawa and Makoto Kobayashi's 1973 article, "CP Violation in the Renormalizable Theory of Weak Interaction", is the fourth most cited high energy physics paper of all time as of 2010. They discovered the origin of the explicit breaking of CP symmetry in the weak interactions. The Cabibbo–Kobayashi–Maskawa matrix, which defines the mixing parameters between quarks, was the result of this work. Kobayashi and Maskawa were awarded the 2008 Nobel Prize in Physics "for the discovery of the origin of the broken symmetry which predicts the existence of at least three families of quarks in nature."Leo Esaki was awarded the 1973 Nobel Prize in Physics for the discovery of electron tunneling (quantum tunnelling) in the 1950s. The tunnel diode (Esaki diode) was invented in August 1957 by Leo Esaki, Yuriko Kurose and Takashi Suzuki when they were working at Tokyo Tsushin Kogyo, now Sony.
Louis J. Cabri
Louis Jean-Pierre Cabri (born February 23, 1934 in Cairo) is an eminent Canadian scientist in the field of platinum group elements (PGE) mineralogy with expertise in precious metal mineralogy and base metals at the Canada Centre for Mineral and Energy Technology (CANMET). First as Research Scientist and later as Principal Scientist (1996–1999). In the 1970s he discovered two new Cu–Fe sulfide minerals, "mooihoekite" and "haycockite". In 1983 he discovered another new mineral, named after him: cabriite (PdSnCu).
Bernard Courtois
Courtois was acknowledged by Humphry Davy and Joseph Louis Gay-Lussac as the true discoverer of iodine. He went into manufacturing high-quality iodine and its salts in 1822. In 1831 he was awarded 6,000 francs as part of the Montyon Prize by "L'Academie royale des sciences" for the medicinal value of this element. He struggled financially for the rest of his life and died September 27, 1838. He was 62 years old and had no assets left for his widow or son. In the year of his death, the "Journal de chimie médicale" drily noted his passing under the heading Obituary as:"Bernard Courtois, the discoverer of iodine, died at Paris the 27th of September, 1838, leaving his widow without fortune. If, on making this discovery, Courtois had taken out a certificate of invention, he would have realized a large estate."
Quark
The quark model was independently proposed by physicists Murray Gell-Mann and George Zweig in 1964. The proposal came shortly after Gell-Mann's 1961 formulation of a particle classification system known as the "Eightfold Way"—or, in more technical terms, SU(3) flavor symmetry, streamlining its structure. Physicist Yuval Ne'eman had independently developed a scheme similar to the Eightfold Way in the same year. An early attempt at constituent organization was available in the Sakata model.
Quartz
Quartz's piezoelectric properties were discovered by Jacques and Pierre Curie in 1880. The quartz oscillator or resonator was first developed by Walter Guyton Cady in 1921. George Washington Pierce designed and patented quartz crystal oscillators in 1923. Warren Marrison created the first quartz oscillator clock based on the work of Cady and Pierce in 1927.
Quantum chromodynamics
With the invention of bubble chambers and spark chambers in the 1950s, experimental particle physics discovered a large and ever-growing number of particles called hadrons. It seemed that such a large number of particles could not all be fundamental. First, the particles were classified by charge and isospin by Eugene Wigner and Werner Heisenberg; then, in 1953–56, according to strangeness by Murray Gell-Mann and Kazuhiko Nishijima (see Gell-Mann–Nishijima formula). To gain greater insight, the hadrons were sorted into groups having similar properties and masses using the "eightfold way", invented in 1961 by Gell-Mann and Yuval Ne'eman. Gell-Mann and George Zweig, correcting an earlier approach of Shoichi Sakata, went on to propose in 1963 that the structure of the groups could be explained by the existence of three flavors of smaller particles inside the hadrons: the quarks.
Quantum chromodynamics
QCD exhibits two main properties:Physicist Murray Gell-Mann (b. 1929) coined the word "quark" in its present sense. It originally comes from the phrase "Three quarks for Muster Mark" in "Finnegans Wake" by James Joyce. On June 27, 1978, Gell-Mann wrote a private letter to the editor of the "Oxford English Dictionary", in which he related that he had been influenced by Joyce's words: "The allusion to three quarks seemed perfect." (Originally, only three quarks had been discovered.)
University of Cambridge
In physics, Ernest Rutherford who is regarded as the father of nuclear physics, spent much of his life at the university where he worked closely with E. J. Williams and Niels Bohr, a major contributor to the understanding of the atom, J. J. Thomson, discoverer of the electron, Sir James Chadwick, discoverer of the neutron, and Sir John Cockcroft and Ernest Walton, responsible for first splitting the atom. J. Robert Oppenheimer, leader of the Manhattan Project that developed the atomic bomb, also studied under Rutherford and Thomson. Joan Curran devised the 'chaff' technique during the Second World War to disrupt radar on enemy planes.
Astronomers Sir John Herschel, Sir Arthur Eddington, Paul Dirac, the discoverer of antimatter and one of the pioneers of quantum mechanics; Stephen Hawking, theoretical physicist and the university's long-serving Lucasian Professor of Mathematics until 2009; and Lord Martin Rees, the current Astronomer Royal and former Master of Trinity College. John Polkinghorne, a mathematician before his entrance into the Anglican ministry, received the Templeton Prize for his work reconciling science and religion.
Strange quark
At first people were reluctant to identify the three-bodies as quarks, instead preferring Richard Feynman's parton description, but over time the quark theory became accepted (see "November Revolution").
Synthetic element
The first discovered purely synthetic element was curium, synthesized in 1944 by Glenn T. Seaborg, Ralph A. James, and Albert Ghiorso by bombarding plutonium with alpha particles. The discoveries of americium, berkelium, and californium followed soon. Einsteinium and fermium were discovered by a team of scientists led by Albert Ghiorso in 1952 while studying the radioactive debris from the detonation of the first hydrogen bomb. The isotopes discovered were einsteinium-253, with a half-life of 20.5 days, and fermium-255, with a half-life of about 20 hours.
Collider Detector at Fermilab
One of CDF's most famous observations is the observation of the top quark in February 1995. The existence of the top quark was hypothesized after the observation of the Upsilon in 1977, which was found to consist of a bottom quark and an anti-bottom quark. The Standard Model, which today is the most widely accepted theory describing the particles and interactions, predicted the existence of three generations of quarks. The first generation quarks are the up and down quarks, second generation quarks are strange and charm, and third generation are top and bottom. The existence of the bottom quark solidified physicists’ conviction that the top quark existed. The top quark was the very last quark to be observed, mostly due to its comparatively high mass. Whereas, the masses of the other quarks range from .005 GeV (up quark) to 4.7GeV (bottom quark), the top quark has a mass of 175 GeV. Only Fermilab’s Tevatron had the energy capability to produce and detect top anti-top pairs. The large mass of the top quark caused the top quark to decay almost instantaneously, within the order of 10 seconds, making it extremely difficult to observe. The Standard Model predicts that the top quark may decay leptonically into a bottom quark and a W boson. This W boson may then decay into a lepton and neutrino (t→Wb→ѵlb). Therefore, CDF worked to reconstruct top events, looking specifically for evidence of bottom quarks, W bosons neutrinos. Finally in February 1995, CDF had enough evidence to say that they had "discovered" the top quark.
Bottom quark
The bottom quark was discovered in 1977 by the Fermilab E288 experiment team led by Leon M. Lederman, when collisions produced bottomonium. Kobayashi and Maskawa won the 2008 Nobel Prize in Physics for their explanation of CP-violation.
Flavour (particle physics)
The terms "strange" and "strangeness" predate the discovery of the quark, but continued to be used after its discovery for the sake of continuity (i.e. the strangeness of each type of hadron remained the same); strangeness of anti-particles being referred to as +1, and particles as −1 as per the original definition. Strangeness was introduced to explain the rate of decay of newly discovered particles, such as the kaon, and was used in the Eightfold Way classification of hadrons and in subsequent quark models. These quantum numbers are preserved under strong and electromagnetic interactions, but not under weak interactions.
Henri Becquerel
Antoine Henri Becquerel (; ; 15 December 1852 – 25 August 1908) was a French physicist, Nobel laureate, and the first person to discover evidence of radioactivity. For work in this field he, along with Marie Skłodowska-Curie and Pierre Curie, received the 1903 Nobel Prize in Physics. The SI unit for radioactivity, the becquerel (Bq), is named after him.
Zc(3900)
The Z(3900) is a hadron, a type of subatomic particle made of quarks, believed to be the first tetraquark that has been observed experimentally. The discovery was made in 2013 by two independent research groups: one using the BES III detector at the Chinese Beijing Electron Positron Collider, the other being part of the Belle experiment group at the Japanese KEK particle physics laboratory.
Quark
In less than a year, extensions to the Gell-Mann–Zweig model were proposed. Sheldon Lee Glashow and James Bjorken predicted the existence of a fourth flavor of quark, which they called "charm". The addition was proposed because it allowed for a better description of the weak interaction (the mechanism that allows quarks to decay), equalized the number of known quarks with the number of known leptons, and implied a mass formula that correctly reproduced the masses of the known mesons.
New Zealand quail
The New Zealand quail ("Coturnix novaezelandiae"), or koreke (the Māori name), has been extinct since 1875. The male and female were similar, except the female was lighter. The first scientist to describe it was Sir Joseph Banks when he visited New Zealand on James Cook's first voyage. Terrestrial and temperate, this species inhabited lowland tussock grassland and open fernlands. The first specimen to be obtained by a European was collected in 1827 by Jean René Constant Quoy and Joseph Paul Gaimard on Dumont D'Urville's voyage. 
Research was conducted between 2007 and 2009 into whether the quails on Tiritiri Matangi Island – which was spared the worst impact of introduced predators – might be a surviving population of this species, or "koreke"-brown quail ("Coturnix ypsilophora") hybrids. However, a genetic study showed instead that the quail on Tiritiri Matangi are Australian brown quail, "Coturnix ypsilophora". Sequences were derived for all quail species within the Australian and New Zealand "Coturnix sp". complex.
James Bjorken
Richard Feynman subsequently reformulated this concept into the parton model, used to understand the quark composition of hadrons at high energies. The predictions of Bjorken scaling were confirmed in the early late 1960s electroproduction experiments at SLAC, in which quarks were seen for the first time. The general idea, with small logarithmic modifications, is explained in quantum chromodynamics by "asymptotic freedom".
Soo-Bong Kim
Kim was a postdoctoral fellow and a research investigator at the University of Michigan before moving to Boston University in 1996. He took up his current position at Seoul National University in 1998. He jointly led the efforts of discovering the top quark in 1994 and measuring its mass in 1995 using the Fermilab Tevatron hadron collider as a member of the CDF collaboration. The top quark was the heaviest fundamental fermion yet to be observed before the experiment. The observation and mass measurement of the particle opened a new field of "top quark physics".
André-Louis Debierne
Debierne studied at the elite École supérieure de physique et de chimie industrielles de la ville de Paris (ESPCI ParisTech). He was a student of Charles Friedel, was a close friend of Pierre and Marie Curie and was associated with their work. In 1899, he discovered the radioactive element actinium, as a result of continuing the work with pitchblende that the Curies had initiated.
Quark
In the following years a number of suggestions appeared for extending the quark model to six quarks. Of these, the 1975 paper by Haim Harari was the first to coin the terms "top" and "bottom" for the additional quarks.
Stephen Quake
Stephen Ronald Quake (born 1969) is an American scientist, inventor and entrepreneur. He earned his B.S. in Physics and M.S. in Mathematics from Stanford in 1991 and his D.Phil. in Physics from Oxford University in 1994 as a Marshall Scholar. His thesis research was in statistical mechanics and the effects of knots on polymers. He did his postdoctoral work at Stanford in single molecule biophysics with Steven Chu. Quake joined the faculty of the California Institute of Technology at the age of 26, where he rose through the ranks and was ultimately appointed the Thomas and Doris Everhart Professor of Applied Physics and Physics. He moved back to Stanford University in 2005 to help launch a new department in Bioengineering, where he is now the Lee Otterson Professor of Bioengineering and Applied Physics, and an Investigator of the Howard Hughes Medical Institute.
The Quirk
The Quirk was a for-charity literary magazine which publishes work from poets and artists across the world. It printed work from a wide array of writers, including W.D. Snodgrass, Yusef Komunyakaa, Robert Bly, Naomi Shihab Nye, Alberto Rios, Dorianne Laux, Daisy Fried, Diane di Prima, Jim Daniels, Alicia Ostriker, and many others. The magazine was founded in 2005 by Kaveh Akbar when he was a high school student. He was also the editor, as a local general interest magazine. After thirteen issues, "The Quirk" premiered its first literary issue.
Daniel Quare
When Quare began his career horology was rapidly advancing. The pendulum was a novelty; so were the spiral spring and anchor escapement invented by Robert Hooke, and the fusee chain. To Quare belongs the honour of inventing repeating watches, and it is also claimed for him that he adapted the concentric minute hand. If he was actually the inventor of the latter, he must have constructed it early in his career, for two concentric hands are shown in a diagram in Christiaan Huygens's "Horologium Oscillatorium" (1673). Clocks and watches made by Quare with only one hand are extant, or with two circles and pointers, one for the hours and another for the minutes, and the concentric invention did not quickly supersede this arrangement even in Quare's own workshop. In the "London Gazette" for 25–29 March 1686, is an advertisement for a lost "pendulum" watch made by Quare, that had only one hand, but was curiously arranged to give the minutes: "it had but 6 hours upon the dial plate, with 6 small cipher figures within every hour; the hand going round every 6 hours, which shows also the minutes between every hour."
Top quark
It was in fact not long until a fifth quark, the bottom, was discovered by the E288 experiment team, led by Leon Lederman at Fermilab in 1977. This strongly suggested that there must also be a sixth quark, the top, to complete the pair. It was known that this quark would be heavier than the bottom, requiring more energy to create in particle collisions, but the general expectation was that the sixth quark would soon be found. However, it took another 18 years before the existence of the top was confirmed.
Quark (hash function)
Quark is a cryptographic hash function (family).
It was designed by Jean-Philippe Aumasson, Luca Henzen, Willi Meier and María Naya-Plasencia.
Quark (Star Trek)
When the Bajoran wormhole was discovered, Quark helped broker deals between several Gamma Quadrant races and the Ferengi. The Alpha Quadrant's first knowledge of the Dominion came through business dealings that Quark and the Ferengi had in the Gamma Quadrant with the Karemma of the Dominion. Quark's role in these dealings came about as a result of the interference of Grand Nagus Zek. Quark became Grand Nagus for a brief period when it appeared that Zek had died; however, Zek's death turned out to be a ruse and Quark was promptly deposed. Along with Commander Sisko, Quark was also among the first to encounter the genetically engineered soldiers of the Dominion, the Jem'Hadar.
Color charge
Shortly after the existence of quarks was first proposed in 1964, Oscar W. Greenberg introduced the notion of color charge to explain how quarks could coexist inside some hadrons in otherwise identical quantum states without violating the Pauli exclusion principle. The theory of quantum chromodynamics has been under development since the 1970s and constitutes an important component of the Standard Model of particle physics.
Xi baryon
The particle is also known as the cascade B particle and contains quarks from all three families. It was discovered by D0 and CDF experiments at Fermilab. The discovery was announced on 12 June 2007. It was the first known particle made of quarks from all three quark generations – namely, a down quark, a strange quark, and a bottom quark. The D0 and CDF collaborations reported the consistent masses of the new state. The Particle Data Group world average mass is .
Ralph A. James
Curium (atomic number 96) was discovered in 1944 by Glenn T. Seaborg, Ralph A. James and Albert Ghiorso during World War II in the Chicago Metallurgical Laboratory, as part of the Manhattan Project, by bombing plutonium with helium ions. It was named in honor of Pierre Curie and Marie Sklodowska Curie.
Isospin
Isospin was introduced as a concept in 1932, well before the 1960s development of the quark model. The man who introduced it, Werner Heisenberg, did so to explain symmetries of the then newly discovered neutron (symbol n):
Down quark
This classification scheme organized the hadrons into isospin multiplets, but the physical basis behind it was still unclear. In 1964, Gell-Mann and George Zweig (independently of each other) proposed the quark model, then consisting only of up, down, and strange quarks. However, while the quark model explained the Eightfold Way, no direct evidence of the existence of quarks was found until 1968 at the Stanford Linear Accelerator Center. Deep inelastic scattering experiments indicated that protons had substructure, and that protons made of three more-fundamental particles explained the data (thus confirming the quark model).
Harald Fritzsch
Harald Fritzsch (born 10 February 1943 in Zwickau, Germany) is a German theoretical physicist known for his contributions to the theory of quarks, the development of Quantum Chromodynamics and the great unification of the standard model of particle physics.
Quark
In 1968, deep inelastic scattering experiments at the Stanford Linear Accelerator Center (SLAC) showed that the proton contained much smaller, point-like objects and was therefore not an elementary particle. Physicists were reluctant to firmly identify these objects with quarks at the time, instead calling them "partons"—a term coined by Richard Feynman. The objects that were observed at SLAC would later be identified as up and down quarks as the other flavors were discovered. Nevertheless, "parton" remains in use as a collective term for the constituents of hadrons (quarks, antiquarks, and gluons).
Strangeness
The terms "strange" and "strangeness" predate the discovery of the quark, and were adopted after its discovery in order to preserve the continuity of the phrase; strangeness of anti-particles being referred to as +1, and particles as −1 as per the original definition. For all the quark flavour quantum numbers (strangeness, charm, topness and bottomness) the convention is that the flavour charge and the electric charge of a quark have the same sign. With this, any flavour carried by a charged meson has the same sign as its charge.
Quantum chromodynamics
Richard Feynman argued that high energy experiments showed quarks are real particles: he called them "partons" (since they were parts of hadrons). By particles, Feynman meant objects which travel along paths, elementary particles in a field theory.
History of chemistry
Pierre and Marie further explored radioactivity by working to separate the substances in uranium ores and then using the electrometer to make radiation measurements to ‘trace’ the minute amount of unknown radioactive element among the fractions that resulted. Working with the mineral pitchblende, the pair discovered a new radioactive element in 1898. They named the element polonium, after Marie's native country of Poland. On December 21, 1898, the Curies detected the presence of another radioactive material in the pitchblende. They presented this finding to the French Academy of Sciences on December 26, proposing that the new element be called radium. The Curies then went to work isolating polonium and radium from naturally occurring compounds to prove that they were new elements. In 1902, the Curies announced that they had produced a decigram of pure radium, demonstrating its existence as a unique chemical element. While it took three years for them to isolate radium, they were never able to isolate polonium. Along with the discovery of two new elements and finding techniques for isolating radioactive isotopes, Curie oversaw the world's first studies into the treatment of neoplasms, using radioactive isotopes. With Henri Becquerel and her husband, Pierre Curie, she was awarded the 1903 Nobel Prize for Physics. She was the sole winner of the 1911 Nobel Prize for Chemistry. She was the first woman to win a Nobel Prize, and she is the only woman to win the award in two different fields.
Nicola Cabibbo
Before the discovery of the third generation of quarks, this work was extended by Makoto Kobayashi and Toshihide Maskawa to the Cabibbo–Kobayashi–Maskawa matrix. In 2008, Kobayashi and Maskawa shared one half of the Nobel Prize in Physics for their work. Some physicists had bitter feelings that the Nobel Prize committee failed to reward Cabibbo for his vital part. Asked for a reaction on the prize, Cabibbo preferred to give no comment. According to sources close to him, however, he was embittered.
Henri Becquerel
In 1889, Becquerel became a member of the Académie des Sciences. In 1900, Becquerel won the Rumford Medal for his discovery of the radioactivity of uranium and he was made an Officer of the Legion of Honour.The Berlin-Brandenburg Academy of Sciences and Humanities awarded him the Helmholtz Medal in 1901. In 1903, Henri shared a Nobel Prize in Physics with Pierre Curie and Marie Curie for the discovery of spontaneous radioactivity. In 1905, he was awarded the Barnard Medal by the U.S. National Academy of Sciences. In 1906, Henri was elected Vice Chairman of the academy, and in 1908, the year of his death, Becquerel was elected Permanent Secretary of the Académie des Sciences. During his lifetime, Becquerel was honored with membership into the Accademia dei Lincei and the Royal Academy of Berlin. Becquerel was elected a Foreign Member of the Royal Society (ForMemRS) in 1908. Becquerel has been honored with being the namesake of many different scientific discoveries. The SI unit for radioactivity, the becquerel (Bq), is named after him. There is a crater named Becquerel on the Moon and also a crater named Becquerel on Mars. The uranium-based mineral becquerelite was named after Henri.
University of Chicago
Notable faculty in physics have included the speed of light calculator A. A. Michelson, elementary charge calculator Robert A. Millikan, discoverer of the Compton Effect Arthur H. Compton, the creator of the first nuclear reactor Enrico Fermi, "the father of the hydrogen bomb" Edward Teller, "one of the most brilliant and productive experimental physicists of the twentieth century" Luis Walter Alvarez, Murray Gell-Mann who introduced the quark, second female Nobel laureate Maria Goeppert-Mayer, the youngest American winner of the Nobel Prize Tsung-Dao Lee, and astrophysicist Subrahmanyan Chandrasekhar.
Quantum
The concept of quantization of radiation was discovered in 1900 by Max Planck, who had been trying to understand the emission of radiation from heated objects, known as black-body radiation. By assuming that energy can be absorbed or released only in tiny, differential, discrete packets (which he called "bundles", or "energy elements"), Planck accounted for certain objects changing colour when heated. On December 14, 1900, Planck reported his findings to the German Physical Society, and introduced the idea of quantization for the first time as a part of his research on black-body radiation. As a result of his experiments, Planck deduced the numerical value of "h", known as the Planck constant, and reported more precise values for the unit of electrical charge and the Avogadro–Loschmidt number, the number of real molecules in a mole, to the German Physical Society. After his theory was validated, Planck was awarded the Nobel Prize in Physics for his discovery in 1918.
Discovery of the neutron
The discoveries of the neutron and positron in 1932 were the start of the discoveries of many new particles. Muons were discovered in 1936. Pions and kaons were discovered in 1947, while lambda particles were discovered in 1950. Throughout the 1950s and 1960s, a large number of particles called hadrons were discovered. A classification scheme for organizing all these particles, proposed independently by Murray Gell-Mann and
George Zweig in 1964, became known as the quark model. By this model, particles such as the proton and neutron were not elementary, but composed of various configurations of a small number of other truly elementary particles called partons or quarks. The quark model received experimental verification beginning in the late 1960s and finally provided an explanation for the neutron's anomalous magnetic moment.
Quark model
The modern concept of color completely commuting with all other charges and providing the strong force charge was articulated in 1973, by William Bardeen, ,
and Murray Gell-Mann.
Franz N. D. Kurie
Franz Newell Devereux Kurie (February 6, 1907 in Victor, Colorado – June 12, 1972) was an American physicist who, while working at Yale in 1933, showed that the neutron was neither a dumbbell-shaped combination of proton and electron, nor an onion-shaped combination of an electron embracing the proton. Consequently, and until the discovery of the quark structure of hadrons, the neutron was assumed to be an elementary particle.
Curium
The discovery of curium, as well as americium, in 1944 was closely related to the Manhattan Project, so the results were confidential and declassified only in 1945. Seaborg leaked the synthesis of the elements 95 and 96 on the U.S. radio show for children, the Quiz Kids, five days before the official presentation at an American Chemical Society meeting on November 11, 1945, when one of the listeners asked whether any new transuranium element beside plutonium and neptunium had been discovered during the war. The discovery of curium (Cm and Cm), their production and compounds were later patented listing only Seaborg as the inventor.
The new element was named after Marie Skłodowska-Curie and her husband Pierre Curie who are noted for discovering radium and for their work in radioactivity. It followed the example of gadolinium, a lanthanide element above curium in the periodic table, which was named after the explorer of the rare earth elements Johan Gadolin:
Quark (technical festival)
Quark also hosted speeches from world famous cartoonist Stephan Pastis and Indian journalist Rajdeep Sardesai. Bollywood actress Aditi Rao Hydari gave a candid talk, while Brendan Eich, the creator of Javascript and co-founder of Mozilla Corp., addressed the audience with his wise words.
Quink
A popular misconception is that the ink was invented by a Filipino, Francisco Quisumbing, and takes its name from 'Quisumbing Ink'. Although this apocryphal tale appears on numerous websites, no is ever cited. The accounts uniformly identify the supposed inventor as 
Francisco Quisumbing, a Filipino botanist who studied in both the Philippines and the US, gaining a PhD in Plant Taxonomy, Systematics and Morphology from the University of Chicago in 1923. What biographical information that can be found is incomplete and unreliable. There is no indication that such a person ever worked for Parker.
Jerome Isaac Friedman
In 1968-69, commuting between MIT and California, he conducted experiments with Henry W. Kendall and Richard E. Taylor at the Stanford Linear Accelerator Center which gave the first experimental evidence that protons had an internal structure, later known to be quarks. For this, Friedman, Kendall and Taylor shared the 1990 Nobel Prize in Physics. He is an Institute Professor at the Massachusetts Institute of Technology. Friedman is also a member of the Board of Sponsors of the Bulletin of the Atomic Scientists.
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. Due to a phenomenon known as "color confinement", quarks are never directly observed or found in isolation; they can be found only within hadrons, which include baryons (such as protons and neutrons) and mesons. For this reason, much of what is known about quarks has been drawn from observations of hadrons.
History of quantum mechanics
In 1923, the French physicist Louis de Broglie put forward his theory of matter waves by stating that particles can exhibit wave characteristics and vice versa. This theory was for a single particle and derived from special relativity theory. Building on de Broglie's approach, modern quantum mechanics was born in 1925, when the German physicists Werner Heisenberg, Max Born, and Pascual Jordan developed matrix mechanics and the Austrian physicist Erwin Schrödinger invented wave mechanics and the non-relativistic Schrödinger equation as an approximation to the generalised case of de Broglie's theory. Schrödinger subsequently showed that the two approaches were equivalent.
Lambda baryon
The Lambda baryon was first discovered in October 1950, by V. D. Hopper and S. Biswas of the University of Melbourne, as a neutral V particle with a proton as a decay product, thus correctly distinguishing it as a baryon, rather than a meson, i.e. different in kind from the K meson discovered in 1947 by Rochester and Butler; they were produced by cosmic rays and detected in photographic emulsions flown in a balloon at . Though the particle was expected to live for , it actually survived for . The property that caused it to live so long was dubbed "strangeness" and led to the discovery of the strange quark. Furthermore, these discoveries led to a principle known as the "conservation of strangeness", wherein lightweight particles do not decay as quickly if they exhibit strangeness (because non-weak methods of particle decay must preserve the strangeness of the decaying baryon).
Electron scattering
Stanford Linear Accelerator Center is located near Stanford University, California. Construction began on the 2 mile long linear accelerator in 1962 and was completed in 1967, and in 1968 the first experimental evidence of quarks was discovered resulting in the 1990 Nobel Prize in Physics, shared by SLAC's Richard Taylor and Jerome I. Friedman and Henry Kendall of MIT. The accelerator came with a 20GeV capacity for the electron acceleration, and while similar to Rutherford's scattering experiment, that experiment operated with alpha particles at only 7MeV. In the SLAC case the incident particle was an electron and the target a proton, and due to the short wavelength of the electron (due to its high energy and momentum) it was able to probe into the proton.
The Stanford Positron Electron Asymmetric Ring (SPEAR) addition to the SLAC made further such discoveries possible, leading to the discovery in 1974 of the J/psi particle, which consists of a paired charm quark and anti-charm quark, and another Nobel Prize in Physics in 1976.
This was followed up with Martin Perl's announcement of the discovery of the tau lepton, for which he shared the 1995 Nobel Prize in Physics.
Fred La Rose
Alfred "Fred" La Rose, also known as "Fred Rose" and "Frederick LaRose" (c. 1870 - September 1940), was a blacksmith from Quebec who discovered silver on September 15, 1903 at the future site of Cobalt, Ontario. He is often referred to as the "Father of Cobalt," an unofficial title shared by the Province of Ontario's first geologist, Dr. W. G. Miller (1866 - 1925).
Neutron
In one of the early successes of the Standard Model (SU(6) theory, now understood in terms of quark behavior), in 1964 Mirza A.B. Beg, Benjamin W. Lee, and Abraham Pais theoretically calculated the ratio of proton to neutron magnetic moments to be −3/2, which agrees with the experimental value to within 3%. The measured value for this ratio is . A contradiction of the quantum mechanical basis of this calculation with the Pauli exclusion principle, led to the discovery of the color charge for quarks by Oscar W. Greenberg in 1964.
Top quark
Its existence (and that of the bottom quark) was postulated in 1973 by Makoto Kobayashi and Toshihide Maskawa to explain the observed CP violations in kaon decay, and was discovered in 1995 by the CDF and DØ experiments at Fermilab. Kobayashi and Maskawa won the 2008 Nobel Prize in Physics for the prediction of the top and bottom quark, which together form the third generation of quarks.
KLOE (experiment)
Data from the original experiment allowed Makoto Kobayashi and Toshihide Maskawa to give the most precise measurement of one of the elements of the quark mixing matrix currently available. They then used this value to discover "the origin of the broken symmetry which predicts the existence of at least three families of quarks in nature", which won them the Nobel Prize in Physics in 2008.
Shoichi Sakata
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, proposed by Gell-Mann and George Zweig 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.
Paris in the Belle Époque
The physicist Henri Becquerel (1852-1908), while studying the fluorescence of uranium salts, discovered radioactivity in 1896, and in 1903 was awarded the Nobel Prize in physics for his discovery. Pierre Curie (1859-1906) and Marie Curie (1867-1934) jointly carried on Becquerel's work, discovering radium and polonium (1898). They jointly received the Nobel Prize for physics in 1903. Marie Curie became the first female professor at the University of Paris and won the Nobel Prize for chemistry in 1911. She was the first woman to be buried in the Panthéon.
Americium
The discovery of americium and curium in 1944 was closely related to the Manhattan Project; the results were confidential and declassified only in 1945. Seaborg leaked the synthesis of the elements 95 and 96 on the U.S. radio show for children "Quiz Kids" five days before the official presentation at an American Chemical Society meeting on 11 November 1945, when one of the listeners asked whether any new transuranium element beside plutonium and neptunium had been discovered during the war. After the discovery of americium isotopes Am and Am, their production and compounds were patented listing only Seaborg as the inventor. The initial americium samples weighed a few micrograms; they were barely visible and were identified by their radioactivity. The first substantial amounts of metallic americium weighing 40–200 micrograms were not prepared until 1951 by reduction of americium(III) fluoride with barium metal in high vacuum at 1100 °C.
Richard Dalitz
Dalitz was directly involved in pioneering quark research since the early 1960s, at a time when leading theorists considered quarks as purely mathematical entities, and he participated in the identification of the top quark. In 1965 he began a series of lectures on the physics of quarks that became a "bible for the relatively few who then took it seriously."
Exotic hadron
When the quark model was first postulated by Murray Gell-Mann and others in the 1960s, it was to organize the states known then to be in existence in a meaningful way. As quantum chromodynamics (QCD) developed over the next decade, it became apparent that there was no reason why only three-quark and quark-antiquark combinations could exist. Indeed, Gell-Mann's original 1964 paper alludes to the possibility of exotic hadrons and classifies hadrons into baryons and mesons depending upon whether they have an odd (baryon) or even (meson) number of valence quarks. In addition, it seemed that gluons, the mediator particles of the strong interaction, could also form bound states by themselves (glueballs) and with quarks (hybrid hadrons). Several decades have passed without conclusive evidence of an exotic hadron that could be associated with the S-matrix pole.
Dyon
Dyons were first proposed by Julian Schwinger in 1969 as a phenomenological alternative to
quarks. He extended the Dirac quantization condition to the dyon and used the model to predict the existence of a particle with the properties of the J/ψ meson prior to its discovery in 1974.