Instruct: Given a question, retrieve passages that can help answer the question.
Query: Who discovered the quark?
The quark model was independently proposed by physicists Murray Gell-Mann and George Zweig in 1964.[5] Quarks were introduced as parts of an ordering scheme for hadrons, and there was little evidence for their physical existence until deep inelastic scattering experiments at the Stanford Linear Accelerator Center in 1968.[6][7] Accelerator experiments have provided evidence for all six flavors. The top quark, first observed at Fermilab in 1995, was the last to be discovered.[5]
Hadrons are categorized into two families: baryons, made of an odd number of quarks – usually three quarks – and mesons, made of an even number of quarks—usually one quark and one antiquark. Protons and neutrons are examples of baryons; pions are an example of a meson. "Exotic" hadrons, containing more than three valence quarks, have been discovered in recent years. A tetraquark state (an exotic meson), named the Z(4430), was discovered in 2007 by the Belle Collaboration and confirmed as a resonance in 2014 by the LHCb collaboration. Two pentaquark states (exotic baryons), named and , were discovered in 2015 by the LHCb collaboration. There are several more exotic hadron candidates, and other colour-singlet quark combinations that may also exist.
Quark inspects the family ledgers and discovers that D'Ghor has for years been using financial scams to weaken the House of Kozak's assets. This is dishonorable conduct for a Klingon, and when Quark exposes D'Ghor's actions before Chancellor Gowron. D'Ghor, in return exposes Quark's lie regarding the circumstances of Kozak's death. D'Ghor challenges Quark to a duel to the death, and to everyone's astonishment Quark shows up for the fight. Quark throws his weapon to the ground, and denounces the duel as no better than an execution since Quark is no warrior. D'Ghor is happy to kill the unarmed Quark anyway, and moves in for the kill. Gowron, disgusted by D'Ghor's conduct, aborts the duel and discommendates D'Ghor on the spot. Gowron, after complimenting Quark for showing exceptional bravery for a Ferengi, rules that there are enough "unusual circumstances" to grant Grilka special dispensation to lead her House in her dead husband's stead. Quark asks the grateful Grilka for a divorce, which she happily and immediately grants.
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.
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.
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.[55] 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.[56] 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."[57] The names "bottom" and "top", coined by Harari, were chosen because they are "logical partners for up and down quarks".[41][42][56] In the past, bottom and top quarks were sometimes referred to as "beauty" and "truth" respectively,[nb 3] but these names have somewhat fallen out of use.[61] While "truth" never did catch on, accelerator complexes devoted to massive production of bottom quarks are sometimes called "beauty factories".[62]
Quark offers Larell ten percent to keep her out of his hair, but he is unable to find the loot. He returns to his quarters to find two alien brothers, Krit and Nahsk. Claiming to be Morn's business associates, they tell Quark that Morn owes them all of the latinum. Quark tries to bargain when Nahsk smashes one of Morn's paintings over Quark's head. The two parties finally agree to a figure of fifty percent, and the brothers leave. Moments later, Quark discovers a storage locker claim slip woven into what's left of the painting.
At the much higher energy of the Large Hadron Collider (LHC) the production of strangeness in quark gluon plasma saturates leading to quark-level chemical equilibrium yield. As the fireball of matter expands and breaks apart, this, in turn, provides a very high abundance of strange hadrons. Among these, heavy mesons composed of strange quarks and a heavy quark, such as bottom () or charm (), are of particular interest. The coincident high yield of charm and strangeness present at LHC will lead to copious production of . Other heavy flavor particles, some which have not even been discovered at this time are also likely to appear. In that way, the Strangeness has turned today more generally into the Quark Flavor signature of quark–gluon plasma.
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.
Mesons are hadrons containing an even number of valence quarks (at least 2). Most well known mesons are composed of a quark-antiquark pair, but possible tetraquarks (4 quarks) and hexaquarks (6 quarks, comprising either a dibaryon or three quark-antiquark pairs) may have been discovered and are being investigated to confirm their nature. Several other hypothetical types of exotic meson may exist which do not fall within the quark model of classification. These include glueballs and hybrid mesons (mesons bound by excited gluons).
The success of the Sakata model is due to the fact that there is a correspondence between the proton, neutron, and Lambda baryon, and the up, down, and strange quarks. The proton contains two up quarks and a down quark, the neutron contains one up quark and two down quarks, while the Lambda baryon contains one up quark, one down quark, and one strange quark. That is, each of these baryons is made of one up and one down quark, and an additional quark: up for the proton, down for the neutron, and strange for the Lambda baryon. Because of this correspondence to the up, down, and strange quarks, the Sakata model has the same SU(3) symmetry as the quark model, and can reproduce the flavour quantum numbers of all hadrons made of up, down and strange quarks. Because the charm quark was not discovered until 1974, the Sakata model remained a staple of particle physics for some time after the quark model had been proposed.
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.
The first omega baryon discovered was the , made of three strange quarks, in 1964. The discovery was a great triumph in the study of quark processes, since it was found only after its existence, mass, and decay products had been predicted in 1961 by the American physicist Murray Gell-Mann and, independently, by the Israeli physicist Yuval Ne'eman. Besides the , a charmed omega particle () was discovered, in which a strange quark is replaced by a charm quark. The decays only via the weak interaction and has therefore a relatively long lifetime. Spin ("J") and parity ("P") values for unobserved baryons are predicted by the quark model.
Zek offers Quark the position of First Clerk. Quark happily accepts – then discovers the Nagus is not the profit-making whiz he once was. By day's end, the Ferengi market exchange has experienced a drastic slide due to the Nagus's failing memory. A stunned Quark returns home, where Ishka reveals that she had been helping Zek. Quark realizes that his mother was more than Zek's lover – she was the power behind the throne. Ishka, in turn, realizes that Quark turned Zek against her, and may have destroyed the Ferengi economy in the process.
The Mirror Universe version of Quark appeared only once, in the episode "". At first he appears much the same as his regular counterpart (although mirror Quark has no idea what 'gold pressed latinum' - a staple of Ferengi currency - is), but it's soon revealed that mirror Quark is actively helping Terran slaves escape the cruelty of the Klingon/Cardassian Alliance. This version of Quark is eventually caught and executed when his activities are discovered.
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 .
The strange quark's existence was indirectly validated by SLAC's scattering experiments: not only was it a necessary component of Gell-Mann and Zweig's three-quark model, but it provided an explanation for the kaon (K) and pion (π) hadrons discovered in cosmic rays in 1947.[37]
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.
This episode also features a subplot involving a DS9 visitor called Tiron (Jeffrey Combs, in the first of many Star Trek appearances), who employs Quark to make him a custom holosuite program featuring a holographic Kira. Quark tries multiple times to get enough data on Kira to make the hologram, and eventually breaks into secure files to accomplish this. Odo and Kira discover the security break, and have a little fun at Quark's expense, by altering the holographic Kira's head to that of Quark's.
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.
Quark repeatedly clashed with FCA (Ferengi Commerce Authority) liquidator Brunt, who believed that Quark was detrimental to Ferengi society and beliefs. The two met initially in a scandal involving Quark's mother Ishka, who had earned profit despite this being illegal for a female. Following this, Brunt was responsible for Quark receiving a savage beating at the hands of Nausicaan thugs. The attack was meant to coerce Quark into dissolving the employee union founded by his brother, Rom. Instead, Quark secretly honored many of the union's demands. Later, when Quark was falsely diagnosed with a fatal disease, Brunt anonymously bought the Ferengi bartender's remains six days in advance. When Quark discovered he was not dying and backed out of the contract, Brunt revoked Quark's business license with glee, but Quark's friends supplied him with all the equipment necessary to continue operating his bar anyway. (The license was later reinstated as part of a deal between Quark and Brunt to break up Zek and Ishka, who had begun a relationship.) When Brunt almost became Grand Nagus, Quark temporarily became a female named Lumba. This was in order to convince FCA commissioner Nilva that allowing Ferengi females to wear clothing was an opportunity for profit. Brunt did not believe the charade for a minute. Nilva, owner of Slug-O-Cola: "The Slimiest Cola In The Galaxy!", on the other hand, was more than convinced that Lumba was a woman, and chased "her" amorously.
Although they return to the station empty-handed, Zek tells Quark and Pel that he intentionally requested more wine than the Dosi could provide in order to make contact with someone from the Dominion. Unfortunately, while Quark and Pel were gone, Rom discovered Pel's true identity. He tells Quark, who instantly faints. When he wakes up, Quark orders Rom not to tell anyone, knowing his own career would be ruined. Pel later reveals her identity to Zek herself, but when Zek threatens to put Quark and Pel in prison, he realizes that he too did business with Pel. The group decides to keep Pel's identity a secret and she leaves to make a new life in the Gamma Quadrant.
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 reminds the group that he must be there to take the delivery, so they agree to split the money five ways. However, the "partners" try to double cross each other, and Quark runs for cover until Odo arrives to arrest the four thieves. Quark excitedly examines the latinum, only to discover that the bars have had all the latinum extracted, leaving mere gold. Resigned to his fate, Quark returns to the bar to find Morn, alive and well. He faked his own death, leaving Quark to get the others out of the way. Morn then reveals where he really hid the latinum — in his second stomach. He regurgitates a few milliliters (100 bricks worth) as a reward for Quark, making the whole experience a worthwhile one after all.
Since 2003 a frontier for the Standard Model (SM) has emerged at low energies through XYZ particle discoveries. The well-established theory of Quantum Chromodynamics (QCD) is tested by many exotic charmonium discoveries since the X(3872) was first identified at the Belle experiment in 2003. The basic model of hadron physics is the assembling of quarks into groups of 3 (baryons) or a quark and anti-quark pair (mesons). A meson with a charm quark and an anti-charm quark is called "charmonium", and the same parallels with the bottom quark and bottomonium. More than two dozen previously unpredicted charmonium- and bottomonium-like states have been discovered, and the understanding of heavy quarkonium physics is undetermined. Previously postulated exotic Standard Model states might apply to these new unique particles. One proposed state is the hybrid state of a quark, anti-quark, and a gluon, sometimes mentioned with charm quarks as an excited charmonium. A multi-quark state of 4 or more quarks (tetraquark, pentaquark, etc.) is also proposed as well as a molecule-like state of multiple mesons. While each of these three types of states have had some success of explaining the newly discovered particle, a complete explanation has not been found.