If you're paying attention, both the bottom quark and the strange quark have a charge of -1/3.
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It was one of these — the bottom quark — that Dr. Lederman and his Fermilab team, outside Chicago, discovered in 19813.
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The Standard Model predicts that around 60% of the time this will create a bottom quark and its antimatter equivalent.
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It implies that the difference in mass between the top and bottom quark must not be larger than a certain value.
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Fusion reactions based on the heavier bottom quark—that is, if the resultant particle actually exists—could release ten times more energy than this xi particle, write the authors.
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But the bottom quarks look much messier in the detector, and it's easy to confuse bottom quark pairs that come from Higgs bosons with those produced in other ways.
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In that paper, published last week on the arXiv physics preprint server, physicists measured the complicated interactions of a kind of B meson containing a bottom quark and a strange quark.
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LHCb focuses on measuring the properties and decays of B mesons, a special combination of two quarks containing antimatter version of the bottom quark and the regular matter version of other kinds of quarks.
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Scientists have since moved on to hunting for CP violation in a new kind of experiment, focusing instead on a heavier combination of particles called "B mesons," those which contain at least one bottom quark.
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All available evidence has made it pretty clear that the new particle was, in fact, the Higgs boson, but spotting the Higgs through the bottom quark decay was much more difficult than finding it via photons or the W and Z bosons.
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Collider Detector at Fermilab. Collider Detector at Fermilab. 28 Apr. 2009 . The existence of the top quark was hypothesized after the observation of the Upsilon at Fermilab in 1977, which was found to consist of a bottom quark and an anti-bottom quark.
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The bottom eta meson () or eta-b meson is a flavourless meson formed from a bottom quark and its antiparticle. It was first observed by the BaBar experiment at SLAC in 2008, and is the lightest particle containing a bottom and anti-bottom quark.
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The bottom quark or b quark, also known as the beauty quark, is a third- generation quark with a charge of − e. All quarks are described in a similar way by electroweak and quantum chromodynamics, but the bottom quark has exceptionally low rates of transition to lower-mass quarks. The bottom quark is also notable because it is a product in almost all top quark decays, and is a frequent decay product of the Higgs boson.
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She worked at Stony Brook University as a postdoctoral fellow. She worked on Fermilab's D0 experiment, building electronics to detect bottom quark particles in real time.
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The bottom quark was first described theoretically in 1973 by physicists Makoto Kobayashi and Toshihide Maskawa to explain CP violation. The name "bottom" was introduced in 1975 by Haim Harari. 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.
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The Upsilon meson () is a quarkonium state (i.e. flavourless meson) formed from a bottom quark and its antiparticle. It was discovered by the E288 experiment team, headed by Leon Lederman, at Fermilab in 1977, and was the first particle containing a bottom quark to be discovered because it is the lightest that can be produced without additional massive particles. It has a lifetime of and a mass about in the ground state.
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For example, the charm quark was first seen in the J/Psi meson () in 1974,J.J. Aubert et al. (1974)J.E. Augustin et al. (1974) and the bottom quark in the upsilon meson () in 1977.
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In particle physics, B mesons are mesons composed of a bottom antiquark and either an up (), down (), strange () or charm quark (). The combination of a bottom antiquark and a top quark is not thought to be possible because of the top quark's short lifetime. The combination of a bottom antiquark and a bottom quark is not a B meson, but rather bottomonium which is something else entirely. Each B meson has an antiparticle that is composed of a bottom quark and an up (), down (), strange () or charm antiquark () respectively.
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In the summer of 1977, a team of physicists, led by Leon M. Lederman, working on Experiment 288, in the proton center beam-line of the Fermilab fixed target areas, discovered the Upsilon (Bottom quark). On 3 September 2008, the discovery of a new particle, the bottom Omega baryon () was announced at the DØ experiment of Fermilab. It is made up of two strange quarks and a bottom quark. This discovery helps to complete the "periodic table of the baryons" and offers insight into how quarks form matter.
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For that reason, mesons containing the bottom quark are exceptionally long-lived for their mass, and are the easiest particles to use to investigate CP violation. Such experiments are being performed at the BaBar, Belle and LHCb experiments.
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2008 Physics Nobel Prize lecture by Makoto Kobayashi2008 Physics Nobel Prize lecture by Toshihide Maskawa On its discovery, there were efforts to name the bottom quark "beauty", but "bottom" became the predominant usage, by analogy of "top" and "bottom" to "up" and "down".
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Depending on the specific details of the SUSY model and the mass hierarchy of the sparticles, the stop might decay into a bottom quark and a chargino, with a subsequent decay of the chargino into the lightest neutralino (which is often the lightest supersymmetric particle).
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The lattice computation of the baryon spectrum was equally impressive. Samuel and Moriarty went on to make mass predictions for hadrons involving the bottom quark that had not yet been produced in accelerators. These predictions were later confirmed except for the one for the baryon.
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The production of single top quarks via weak interaction is a distinctly different process. This can happen in several ways (called channels): Either an intermediate W-boson decays into a top and antibottom quarks ("s-channel") or a bottom quark (probably created in a pair through the decay of a gluon) transforms to a top quark by exchanging a W boson with an up or down quark ("t-channel"). A single top quark can also be produced in association with a W boson, requiring an initial-state bottom quark ("tW- channel"). The first evidence for these processes was published by the DØ collaboration in December 2006, and in March 2009 the CDF and DØ collaborations released twin articles with the definitive observation of these processes.
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From 2002 to 2004, Lockyer served as co-spokesperson for a 600-person international collaboration known as CDF, the Collider Detector at Fermilab experiment at the laboratory's Tevatron particle accelerator. The project achieved world acclaim for discovering and studying the top quark, one of the fundamental building blocks of nature, a counterpart to the bottom quark.
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Taylor graduated from the University of British Columbia with Bachelors of Science in Physics in 1991. As an undergraduate, she worked at TRIUMF, working on rare kaon decay. She completed her graduate studies at the University of Toronto, where she earned a PhD under the supervision of Pekka Sinervo in 1999. She worked on fragmentation properties of the bottom quark.
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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.Lankford, Andy.
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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.
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The bottom quark's "bare" mass is around - a bit more than four times the mass of a proton, and many orders of magnitude larger than common "light" quarks. Although it almost-exclusively transitions from or to a top quark, the bottom quark can decay into either an up quark or charm quark via the weak interaction. CKM matrix elements Vub and Vcb specify the rates, where both these decays are suppressed, making lifetimes of most bottom particles (~10−12 s) somewhat higher than those of charmed particles (~10−13 s), but lower than those of strange particles (from ~10−10 to ~10−8 s). The combination of high mass and low transition-rate gives experimental collision byproducts containing a bottom quark a distinctive signature that makes them relatively easy to identify using a technique called "B-tagging".
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The top quark interacts with gluons of the strong interaction and is typically produced in hadron colliders via this interaction. However, once produced, the top (or antitop) can decay only through the weak force. It decays to a W boson and either a bottom quark (most frequently), a strange quark, or, on the rarest of occasions, a down quark. The Standard Model determines the top quark's mean lifetime to be roughly .
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In 1956, Lederman worked on parity violation in weak interactions. R. L. Garwin, Leon Lederman, and R. Weinrich modified an existing cyclotron experiment, and they immediately verified the parity violation. They delayed publication of their results until after Wu's group was ready, and the two papers appeared back-to-back in the same physics journal. Among his achievements are the discovery of the muon neutrino in 1962 and the bottom quark in 1977.
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However a contains one up, one strange, and one bottom quark, while a contains one up and two bottom quarks. In 2012, the CMS experiment at the Large Hadron Collider detected a baryon (reported mass ). The LHCb experiment at CERN discovered two new Xi baryons in 2014: and . In 2017, the LHCb researchers reported yet another Xi baryon: the double charmed baryon, consisting of two heavy charm quarks and one up quark.
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The large mass of the top quark caused the top quark to decay almost instantaneously, within the order of 10−25 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.
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Leptoquarks, predicted to be nearly as heavy as an atom of lead, could only be created at high energies, and would decay rapidly. A so-called third generation leptoquark, for example, might decay into a bottom quark and a tau lepton. Some theorists proposed that data recorded in experiments at the HERA accelerator at DESY could hint at leptoquarks, which would be a new force that bonds positrons and quarks. Also preons at high energies were considered.
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Although tetraquarks with two quarks and two antiquarks can be considered mesons they are not listed here. The symbols encountered in these lists are: I (isospin), J (total angular momentum), P (parity), C (C-parity), G (G-parity), u (up quark), d (down quark), s (strange quark), c (charm quark), b (bottom quark), Q (charge), B (baryon number), S (strangeness), C (charm), and B′ (bottomness), as well as a wide array of subatomic particles (hover for name).
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The opened Belle II detector before installation of the inner tracking detectors. The Belle II experiment is a particle physics experiment designed to study the properties of B mesons (heavy particles containing a bottom quark). Belle II is the successor to the Belle experiment, and is currently being commissioned at the SuperKEKB accelerator complex at KEK in Tsukuba, Ibaraki Prefecture, Japan. The Belle II detector was "rolled in" (moved into the collision point of SuperKEKB) in April 2017.
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Isgur become the head of the Theory Group at Jefferson Lab in 1990 and eventually became the chief scientist in 1996. He joined the faculty at the College of William & Mary at Williamsburg. Isgur and Mark Wise studied the semileptonic decays of mesons with a charm and bottom quark and they discovered what is now known as the heavy quark symmetry of QCD. This symmetry, which becomes exact for infinitely heavy quarks, leads to important simplifications of form- factors in such decays.
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Lockyer is a fellow of the American Physical Society and is well known in the physics community for his work on the particle known as the bottom quark. In 2006, Lockyer was awarded the American Physical Society's W.K.H. Panofsky Prize for having measured the abnormally long lifetime of the B quark while at SLAC's Mark-II. In 2014 Lockyer received the Pinnacle Achievement Bryden Award from York University for achievement in his field. In May 2015, Lockyer received an honorary doctoral degree from Northern Illinois University.
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The LHCb (Large Hadron Collider beauty) experiment is one of eight particle physics detector experiments collecting data at the Large Hadron Collider at CERN. LHCb is a specialized b-physics experiment, designed primarily to measure the parameters of CP violation in the interactions of b-hadrons (heavy particles containing a bottom quark). Such studies can help to explain the matter-antimatter asymmetry of the Universe. The detector is also able to perform measurements of production cross sections, exotic hadron spectroscopy, charm physics and electroweak physics in the forward region.
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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.
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Several tetraquark candidates have been reported by particle physics experiments in the 21st century. The quark contents of these states are almost all qQ, where q represents a light (up, down or strange) quark, Q represents a heavy (charm or bottom) quark, and antiquarks are denoted with an overline. The existence and stability of tetraquark states with the qq (or QQ) have been discussed by theoretical physicists for a long time, however these are yet to be reported by experiments. Colour flux tubes produced by four static quark and antiquark charges, computed in lattice QCD.
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A W′-boson could be detected at hadron colliders through its decay to lepton plus neutrino or top quark plus bottom quark, after being produced in quark-antiquark annihilation. The LHC reach for W′ discovery is expected to be a few TeV. Direct searches for Z′-bosons are carried out at hadron colliders, since these give access to the highest energies available. The search looks for high-mass dilepton resonances: the Z′-boson would be produced by quark-antiquark annihilation and decay to an electron-positron pair or a pair of opposite-charged muons.
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The Ξb baryon is made of a down, a strange and a bottom quark, making it the first observed baryon formed of quarks from all three generations of matter. The original quark hypotheses by Murray Gell-Mann and George Zweig noted that exotic mesons containing two quarks and two antiquarks (instead of just a quark and antiquark) are possible. Examples were finally observed 40 years later in cases where the exotic meson contains the more distinctive heavy b- and c-quarks. DØ has contributed new understanding of these heavy flavor exotic states.
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At Kyoto University in the early 1970s, he collaborated with Makoto Kobayashi on explaining broken symmetry (the CP violation) within the Standard Model of particle physics. Maskawa and Kobayashi's theory required that there be at least three generations of quarks, a prediction that was confirmed experimentally four years later by the discovery of the bottom quark. Maskawa and 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. The Cabibbo–Kobayashi–Maskawa matrix, which defines the mixing parameters between quarks was the result of this work.
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Throughout the runs with the upgraded detector, the UA2 collaboration was in competition with experiments at Fermilab in the US in the search for the top quark. Physicists had anticipated its existence since 1977, when its partner — the bottom quark — was discovered. It was felt that the discovery of the top quark was imminent. During the 1987-1990 run UA2 collected 2065 W \rightarrow e u decays, and 251 Z decays to electron pairs, from which the ratio of the mass of the W boson and the mass of the Z boson could be measured with a precision of 0.5%.
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In the same year there were the first tests of X-ray lithography at DESY, a procedure that was later refined to X-ray depth lithography. In 1987 the ARGUS detector of the DORIS storage ring was the first place where the conversion of a B-meson into its antiparticle, the anti-B-meson was observed. From this one could conclude that it was possible, for the second-heaviest quark - the bottom-quark - under certain circumstances to convert into a different quark. One could also conclude from this that the unknown sixth quark - the top quark - had to possess a huge mass.
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Like all flavour quantum numbers, topness is preserved under strong and electromagnetic interactions, but not under weak interaction. However the top quark is extremely unstable, with a half-life under 10−23 s, which is the required time for the strong interaction to take place. For that reason the top quark does not hadronize, that is it never forms any meson or baryon, so the topness of a meson or a baryon is always zero. By the time it can interact strongly it has already decayed to another flavour of quark (usually to a bottom quark).
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The particle is a "doubly strange" baryon containing two strange quarks and a bottom quark. A discovery of this particle was first claimed in September 2008 by physicists working on the DØ experiment at the Tevatron facility of the Fermi National Accelerator Laboratory. However, the reported mass of was significantly higher than expected in the quark model. The apparent discrepancy from the Standard Model has since been dubbed the " puzzle". In May 2009, the CDF collaboration made public their results on the search for the based on analysis of a data sample roughly four times the size of the one used by the DØ experiment.
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Nicola Cabibbo and Makoto Kobayashi Paul Krugman, Roger Tsien, Martin Chalfie, Osamu Shimomura, Makoto Kobayashi and Toshihide Masukawa, Nobel Prize Laureates 2008, at a press conference at the Swedish Academy of Science in Stockholm. After completing his doctoral research at Nagoya University in 1972, Kobayashi worked as a research associate on particle physics at Kyoto University. Together, with his colleague Toshihide Maskawa, he worked on explaining CP-violation within the Standard Model of particle physics. Kobayashi and Maskawa's theory required that there were at least three generations of quarks, a prediction that was confirmed experimentally four years later by the discovery of the bottom quark.
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The starting points of the tracks yield useful information for identifying particles; for example, if a group of tracks seem to originate from a point other than the original proton–proton collision, this may be a sign that the particles came from the decay of a hadron with a bottom quark (see b-tagging). The Inner Detector has three parts, which are explained below. The Pixel Detector, the innermost part of the detector, contains three concentric layers and three disks on each end-cap, with a total of 1,744 modules, each measuring 2 centimetres by 6 centimetres. The detecting material is 250 µm thick silicon.
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Quarkonia are bound states of heavy flavour quarks (charm or bottom) and their antiquarks. Two types of quarkonia have been extensively studied: charmonia, which consist of a charm quark and an anti-charm, and bottomonia made of a bottom and an anti-bottom quark. Charm and anticharm quarks in the presence of the Quark Gluon Plasma, in which there are many free colour charges, are not able to see each other any more and therefore they cannot form bound states. The "melting" of quarkonia into the QGP manifests itself in the suppression of the quarkonium yields compared to the production without the presence of the QGP.
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The symbols encountered in these lists are: I (isospin), J (total angular momentum), P (parity), u (up quark), d (down quark), s (strange quark), c (charm quark), t (top quark), b (bottom quark), Q (electric charge), S (strangeness), C (charmness), B′ (bottomness), T (topness), as well as other subatomic particles (hover for name). Antiparticles are not listed in the table; however, they simply would have all quarks changed to antiquarks (and vice versa), and Q, B, S, C, B′, T, would be of opposite signs. I, J, and P values in red have not been firmly established by experiments, but are predicted by the quark model and are consistent with the measurements.C. Amsler et al.
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Since CP violations were seen in neutral kaon decays already in 1964, the emergence of the Standard Model soon after was a clear signal of the existence of a third generation of quarks, as pointed out in 1973 by Kobayashi and Maskawa. The discovery of the bottom quark at Fermilab (by Leon Lederman's group) in 1976 therefore immediately started off the search for the missing third-generation quark, the top quark. Note, however, that the specific values of the angles are not a prediction of the standard model: they are open, unfixed parameters. At this time, there is no generally accepted theory that explains why the measured values are what they are.
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The true analogs of positronium in the theory of strong interactions, however, are not exotic atoms but certain mesons, the quarkonium states, which are made of a heavy quark such as the charm or bottom quark and its antiquark. (Top quarks are so heavy that they decay through the weak force before they can form bound states.) Exploration of these states through non-relativistic quantum chromodynamics (NRQCD) and lattice QCD are increasingly important tests of quantum chromodynamics. Muonium, despite its name, is not an onium containing a muon and an antimuon, because IUPAC assigned that name to the system of an antimuon bound with an electron. However, the production of a muon–antimuon bound state, which is an onium, has been theorized.
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CLEO was a general purpose particle detector at the Cornell Electron Storage Ring (CESR), and the name of the collaboration of physicists who operated the detector. The name CLEO is not an acronym; it is short for Cleopatra and was chosen to go with CESR (pronounced Caesar).Berkelman (2004) p. 24 CESR was a particle accelerator designed to collide electrons and positrons at a center- of-mass energy of approximately 10 GeV. The energy of the accelerator was chosen before the first three bottom quark Upsilon resonances were discovered between 9.4 GeV and 10.4 GeV in 1977. The fourth Υ resonance, the Υ(4S), was slightly above the threshold for, and therefore ideal for the study of, B meson production.
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Since different standard model fermions are grouped together in larger representations, GUTs specifically predict relations among the fermion masses, such as between the electron and the down quark, the muon and the strange quark, and the tau lepton and the bottom quark for and . Some of these mass relations hold approximately, but most don't (see Georgi-Jarlskog mass relation). The boson matrix for is found by taking the matrix from the representation of and adding an extra row and column for the right-handed neutrino. The bosons are found by adding a partner to each of the 20 charged bosons (2 right-handed W bosons, 6 massive charged gluons and 12 X/Y type bosons) and adding an extra heavy neutral Z-boson to make 5 neutral bosons in total.
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Working with Dimitri Nanopoulos and Mary Gaillard, he proposed in 1976 the so-called "Higgs-strahlung" process in which a Higgs boson is radiated from a Z-boson (this proved to be the best way to search for the Higgs boson at the Large Electron–Positron Collider), and in the same year estimated the direct CP-violation contribution to rare neutral kaon decays (which led to the success of the NA31 and NA48 experiments at CERN). Also in 1976, he published two papers suggesting techniques for finding the gluon in annihilations. The following year he predicted the mass of the bottom quark on the basis of Grand Unified Theory, before this quark was observed in experiment. In 1978 he published a frequently cited general paper on such theories, with Andrzej J. Buras, Gaillard and Nanopoulos.
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In quantum field theory, soft-collinear effective theory (or SCET) is a theoretical framework for doing calculations that involve interacting particles carrying widely different energies. The motivation for developing SCET was to control the infrared divergences that occur in quantum chromodynamics (QCD) calculations that involve particles that are soft—carrying much lower energy or momentum than other particles in the process—or collinear—traveling in the same direction as another particle in the process. SCET is an effective theory for highly energetic quarks interacting with collinear and/or soft gluons. It has been used for calculations of the decays of B mesons (quark-antiquark bound states involving a bottom quark) and the properties of jets (sprays of hadrons that emerge from particle collisions when a quark or gluon is produced).
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Beyond this idealization of massless quarks, the actual small quark masses also break the chiral symmetry explicitly as well (providing non- vanishing pieces to the divergence of chiral currents, commonly referred to as PCAC: partially conserved axial currents). The masses of the pseudoscalar meson octet are specified by an expansion in the quark masses which goes by the name of chiral perturbation theory. The internal consistency of this argument is further checked by lattice QCD computations, which allow one to vary the quark mass and confirm that the variation of the pseudoscalar masses with the quark masses is as dictated by chiral perturbation theory, effectively as the square-root of the quark masses. For the three heavy quarks: the charm quark, bottom quark, and top quark, their masses, and hence the explicit breaking these amount to, are much larger than the QCD spontaneous chiral symmetry breaking scale.
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Glueballs are predicted by quantum chromodynamics to be massive, despite the fact that gluons themselves have zero rest mass in the Standard Model. Glueballs with all four possible combinations of quantum numbers P (parity) and C (C parity) for every possible total angular momentum have been considered, producing at least fifteen possible glueball states including excited glueball states that share the same quantum numbers but have differing masses with the lightest states having masses as low as 1.4 GeV/c2 (for a glueball with quantum numbers J=0, P=+, C=+), and the heaviest states having masses as great as almost 5 GeV/c2 (for a glueball with quantum numbers J=0, P=+, C=-). These masses are on the same order of magnitude as the masses of many experimentally observed mesons and baryons, as well as to the masses of the tau lepton, charm quark, bottom quark, some hydrogen isotopes, and some helium isotopes.
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The discovery of this oscillatory behavior > is thus another reinforcement of the Standard Model's durability ... > > CDF physicists have previously measured the rate of the matter-antimatter > transitions for the B meson, which consists of the heavy bottom quark bound > by the strong nuclear interaction to a strange antiquark. Now they have > achieved the standard for a discovery in the field of particle physics, > where the probability for a false observation must be proven to be less than > about 5 in 10 million (). For CDF's result the probability is even smaller, > at 8 in 100 million Ronald Kotulak, writing for the Chicago Tribune, called the particle "bizarre" and stated that the meson "may open the door to a new era of physics" with its proven interactions with the "spooky realm of antimatter". On 14 May 2010, physicists at the Fermi National Accelerator Laboratory reported that the oscillations decayed into matter 1% more often than into antimatter, which may help explain the abundance of matter over antimatter in the observed Universe.
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She has served on several committees of the American Physical Society, advisory panels for the Department of Energy and the United States National Research Council, and on a number of advisory and visiting committees at universities and national laboratories. She was a member of the National Science Board from 1996-2002. Her research accomplishments include pioneering work with Benjamin W. Lee on the evaluation of strong interaction corrections to weak transitions, including the successful prediction of the mass of the charm quark; work with John Ellis and others on the analysis of final states in electron-positron collisions, including the prediction of Three-jet events, and studies of unified gauge theories, including the prediction of the bottom quark mass; studies with Michael Chanowitz of signatures at proton-proton colliders which showed, on very general grounds, that new physics must show up at sufficiently high energies. Her work in recent years has focused on effective supergravity theories based on superstrings, and their implications for phenomena that may be detected both in accelerator experiments and cosmological observations.
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