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Encyclopedia > W and Z bosons
W± and Z Bosons
Composition Elementary particle
Family Boson
Group Gauge boson
Interaction Weak interaction
Theorized Glashow, Weinberg, Salam (1968)
Discovered UA1 and UA2 collaborations, 1983
Mass W: 80.398±0.25 GeV/c2 [1]
Z: 91.1876±0.0021 GeV/c2 [2]
Electric charge W: ±1 e
Z: 0 e
Spin 1
This box: view  talk  edit

In physics, the W and Z bosons, colloquially known as Weakons, are the elementary particles that mediate the weak force. Their discovery has been heralded as a major success for the Standard Model of particle physics. For the novel, see The Elementary Particles. ... In particle physics, bosons are particles with an integer spin, as opposed to fermions which have half-integer spin. ... Gauge bosons are bosonic particles which act as carriers of the fundamental forces of Nature. ... A fundamental interaction or fundamental force is a mechanism by which particles interact with each other, and which cannot be explained in terms of another interaction. ... The weak interaction (often called the weak force or sometimes the weak nuclear force) is one of the four fundamental interactions of nature. ... Professor Sheldon Lee Glashow (born December 5, 1932) is an American physicist. ... Steven Weinberg (born May 3, 1933) is an American physicist. ... For other uses, see Abdus Salam (disambiguation). ... Year 1968 (MCMLXVIII) was a leap year starting on Monday (link will display full calendar) of the Gregorian calendar. ... The UA1 high energy physics experiment ran at CERN from 1981 until 1993 on the SPS collider. ... The UA2 high energy physics experiment was one of the two major experiments and collaborations at the CERN proton-antiproton collider, and codiscovered the W and Z bosons in 1983. ... For the Jimi Hendrix song, see 1983. ... The invariant mass or intrinsic mass or proper mass or just mass is a measurement or calculation of the mass of an object that is the same for all frames of reference. ... The elementary charge (symbol e or sometimes q) is the electric charge carried by a single proton, or equivalently, the negative of the electric charge carried by a single electron. ... The elementary charge (symbol e or sometimes q) is the electric charge carried by a single proton, or equivalently, the negative of the electric charge carried by a single electron. ... In physics, spin refers to the angular momentum intrinsic to a body, as opposed to orbital angular momentum, which is the motion of its center of mass about an external point. ... A magnet levitating above a high-temperature superconductor demonstrates the Meissner effect. ... In particle physics, an elementary particle is a particle of which other, larger particles are composed. ... The weak nuclear force or weak interaction is one of the four fundamental forces of nature. ... The Standard Model of Fundamental Particles and Interactions For the Standard Model in Cryptography, see Standard Model (cryptography). ... Thousands of particles explode from the collision point of two relativistic (100 GeV per nucleon) gold ions in the STAR detector of the Relativistic Heavy Ion Collider. ...


The W particle is named after the weak nuclear force. The Z particle was semi-humorously given its name because it was said to be the last particle to need discovery. Another explanation is that the Z particle derives its name from the fact that it has zero electric charge. This box:      Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. ...

Contents

Basic properties

Two kinds of W bosons exist with +1 and −1 elementary units of electric charge; the W+ is the antiparticle of the W. The Z boson (or Z) is electrically neutral and is its own antiparticle. All three particles are very short-lived with a mean life of about 3×10−25 s. In particle physics, bosons are particles with an integer spin, as opposed to fermions which have half-integer spin. ... This box:      Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. ... Corresponding to most kinds of particle, there is an associated antiparticle with the same mass and opposite charges. ... In physics, a neutral particle is a particle with no electric charge. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ...


These bosons are heavyweights among the elementary particles. With a mass of 80.4 GeV/c2 and 91.2 GeV/c2, respectively, the W and Z particles are almost 100 times as massive as the proton—heavier than entire atoms of iron. The mass of these bosons are significant because they limit the range of the weak nuclear force. The electromagnetic force, by contrast, has an infinite range because its boson (the photon) is massless. For other uses, see Proton (disambiguation). ... For other uses, see Atom (disambiguation). ... Fe redirects here. ... For other uses, see Mass (disambiguation). ... This box:      Electromagnetism is the physics of the electromagnetic field: a field which exerts a force on particles that possess the property of electric charge, and is in turn affected by the presence and motion of those particles. ... In modern physics the photon is the elementary particle responsible for electromagnetic phenomena. ...


All three types have a spin of 1. In physics, spin refers to the angular momentum intrinsic to a body, as opposed to orbital angular momentum, which is the motion of its center of mass about an external point. ...


The emission of a W+ or W boson can either raise or lower electric charge of the emitting particle by 1 unit, and alter the spin by 1 unit. At the same time a W boson can change the generation of the particle, for example changing a strange quark to an up quark. The Z boson cannot change either electric charge nor any other charges (like strangeness, charm, etc.), only spin and momentum, so it never changes the generation or flavor of the particle emitting it (see weak neutral current). The strange quark is a second-generation quark with a charge of -(1/3)e and a strangeness of −1. ... The up quark is a first-generation quark with a charge of +(2/3)e. ... A neutral current is one of the ways in which subatomic particles can interact by means of the weak nuclear force. ...


The weak nuclear force

The Feynman diagram for beta decay of a neutron into a proton, electron, and electron antineutrino via an intermediate heavy W boson
The Feynman diagram for beta decay of a neutron into a proton, electron, and electron antineutrino via an intermediate heavy W boson

The W and Z bosons are carrier particles that mediate the weak nuclear force, much like the photon is the carrier particle for the electromagnetic force. The W boson is best known for its role in nuclear decay. Consider, for example, the beta decay of cobalt-60, an important process in supernova explosions. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... In this Feynman diagram, an electron and positron annihilate and become a quark-antiquark pair. ... This article or section does not adequately cite its references or sources. ... For other uses, see Proton (disambiguation). ... For other uses, see Electron (disambiguation). ... For other uses, see Neutrino (disambiguation). ... In physics, the W and Z bosons are the elementary particles that mediate the weak nuclear force. ... Radioactive decay is the set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles. ... In nuclear physics, beta decay (sometimes called neutron decay) is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted. ... For other uses, see Cobalt (disambiguation). ... For other uses, see Supernova (disambiguation). ...

6027Co6028Ni + e + νe

This reaction does not involve the whole cobalt-60 nucleus, but affects only one of its 33 neutrons. The neutron is converted into a proton while also emitting an electron (called a beta particle in this context) and an antineutrino: Cobalt 60 is a Front 242 side project featuring Front 242s Jean-Luc de Meyer and Dominique Lallement. ... Nickel (Ni) Standard atomic mass: 58. ... For other uses, see Electron (disambiguation). ... An antineutrino is the antimatter equivalent particle of the neutrino. ... The nucleus of an atom is the very small dense region, of positive charge, in its centre consisting of nucleons (protons and neutrons). ... This article or section does not adequately cite its references or sources. ... For other uses, see Proton (disambiguation). ... For other uses, see Electron (disambiguation). ... Alpha radiation consists of helium nuclei and is readily stopped by a sheet of paper. ... Antineutrinos, the antiparticles of neutrinos, are neutral particles produced in nuclear beta decay. ...

n0p+ + e + νe

Again, the neutron is not an elementary particle but a composite of an up quark and two down quarks (udd). It is in fact one of the down quarks that interacts in beta decay, turning into an up quark to form a proton (uud). At the most fundamental level, then, the weak force changes the flavor of a single quark: This article or section does not adequately cite its references or sources. ... For other uses, see Proton (disambiguation). ... For other uses, see Electron (disambiguation). ... An antineutrino is the antimatter equivalent particle of the neutrino. ... The up quark is a first-generation quark with a charge of +(2/3)e. ... The down quark is a first-generation quark with a charge of -(1/3)e. ... In particle physics, flavor is a property of a fermion that identifies it, a label that specifies the name of the particle. ...

du + W

which is immediately followed by decay of the W itself: The down quark is a first-generation quark with a charge of -(1/3)e. ... The up quark is a first-generation quark with a charge of +(2/3)e. ...

We + νe

Being its own antiparticle, the Z boson has all zero quantum numbers. The exchange of a Z boson between particles, called a neutral current interaction, therefore leaves the interacting particles unaffected, except for a transfer of momentum. Unlike beta decay, the observation of neutral current interactions requires huge investments in particle accelerators and detectors, such as are available in only a few high-energy physics laboratories in the world. For other uses, see Electron (disambiguation). ... An antineutrino is the antimatter equivalent particle of the neutrino. ... A neutral current is one of the ways in which subatomic particles can interact by means of the weak nuclear force. ... This article is about momentum in physics. ... Atom Smasher redirects here. ... A detector is a device that detects or measures some phenomenon or stimulus, and produces some signal in response. ... Particle physics is a branch of physics that studies the elementary constituents of matter and radiation, and the interactions between them. ...


Predicting the W and Z

A Feynman diagram showing the exchange of a pair of W bosons. This is one of the leading terms contributing to neutral Kaon oscillation.
A Feynman diagram showing the exchange of a pair of W bosons. This is one of the leading terms contributing to neutral Kaon oscillation.

Following the spectacular success of quantum electrodynamics in the 1950s, attempts were undertaken to formulate a similar theory of the weak nuclear force. This culminated around 1968 in a unified theory of electromagnetism and weak interactions by Sheldon Glashow, Steven Weinberg, and Abdus Salam, for which they shared the 1979 Nobel Prize in physics. Their electroweak theory postulated not only the W bosons necessary to explain beta decay, but also a new Z boson that had never been observed. Image File history File links This is a lossless scalable vector image. ... Image File history File links This is a lossless scalable vector image. ... In this Feynman diagram, an electron and positron annihilate and become a quark-antiquark pair. ... In particle physics, Kaons (also called K-mesons and denoted K) are a group of four mesons distinguished by the fact that they carry a quantum number called strangeness. ... Quantum electrodynamics (QED) is a relativistic quantum field theory of electrodynamics. ... The 1950s decade refers to the years 1950 to 1959 inclusive. ... Year 1968 (MCMLXVIII) was a leap year starting on Monday (link will display full calendar) of the Gregorian calendar. ... Professor Sheldon Lee Glashow (born December 5, 1932) is an American physicist. ... Steven Weinberg (born May 3, 1933) is an American physicist. ... For other uses, see Abdus Salam (disambiguation). ... In physics, the electroweak theory presents a unified description of two of the four fundamental forces of nature: electromagnetism and the weak nuclear force. ...


The fact that the W and Z bosons have mass while photons are massless was a major obstacle in developing electroweak theory. These particles are accurately described by an SU(2) gauge theory, but the bosons in a gauge theory must be massless. As a case in point, the photon is massless because electromagnetism is described by a U(1) gauge theory. Some mechanism is required to break the SU(2) symmetry, giving mass to the W and Z in the process. One explanation, the Higgs mechanism, was forwarded by Peter Higgs in the late 1960s. It predicts the existence of yet another new particle, the Higgs boson. In physics, gauge theories are a class of physical theories based on the idea that symmetry transformations can be performed locally as well as globally. ... In modern physics the photon is the elementary particle responsible for electromagnetic phenomena. ... This box:      The Higgs mechanism, also called the Brout-Englert-Higgs mechanism, Higgs-Kibble mechanism or Anderson-Higgs mechanism, was proposed in 1964 by Robert Brout and Francois Englert [1], independently by Peter Higgs [2] and by Gerald Guralnik, C. R. Hagen, and Tom Kibble [3] following earlier work by... Peter Ware Higgs (born May 29, 1929), FRSE, FRS, until recently held a personal chair in theoretical physics at the University of Edinburgh and is now an emeritus professor. ... The 1960s decade refers to the years from the beginning of 1960 to the end of 1969. ... The Higgs boson, also known as the God particle, is a hypothetical massive scalar elementary particle predicted to exist by the Standard Model of particle physics. ...


The combination of the SU(2) gauge theory of the weak interaction, the electromagnetic interaction, and the Higgs mechanism is known as the Glashow-Weinberg-Salam model. These days it is widely accepted as one of the pillars of the Standard Model of particle physics. As of 2008, despite intensive search for the Higgs boson carried out at CERN and Fermilab, its existence remains the main prediction of the Standard Model not to be confirmed experimentally. 2008 (MMVIII) will be a leap year starting on Tuesday of the Gregorian calendar. ... CERN logo The European Organization for Nuclear Research (French: ), commonly known as CERN (see Naming), pronounced (or in French), is the worlds largest particle physics laboratory, situated just northwest of Geneva on the border between France and Switzerland. ... Aerial view of the Fermilab site. ...


Discovery

The discovery of the W and Z particles is a major CERN success story. First, in 1973, came the observation of neutral current interactions as predicted by electroweak theory. The huge Gargamelle bubble chamber photographed the tracks of a few electrons suddenly starting to move, seemingly of their own accord. This is interpreted as a neutrino interacting with the electron by the exchange of an unseen Z boson. The neutrino is otherwise undetectable, so the only observable effect is the momentum imparted to the electron by the interaction. Gargamelle was a giant particle detector at CERN, designed mostly for the detection of neutrinos. ... A bubble chamber A bubble chamber is a vessel filled with a superheated transparent liquid used to detect electrically charged particles moving through it. ... For other uses, see Neutrino (disambiguation). ...


The discovery of the W and Z particles themselves had to wait for the construction of a particle accelerator powerful enough to produce them. The first such machine that became available was the Super Proton Synchrotron, where unambiguous signals of W particles were seen in January 1983 during a series of experiments conducted by Carlo Rubbia and Simon van der Meer. (The actual experiments were called UA1 (led by Rubbia) and UA2 (led by Darriulat), and were the collaborative effort of many people. Van der Meer was the driving force on the accelerator end (stochastic cooling).) UA1 and UA2 found the Z a few months later, in May 1983. Rubbia and van der Meer were promptly awarded the 1984 Nobel Prize in physics, a most unusual step for the conservative Nobel Foundation. Atom Smasher redirects here. ... The Super Proton Synchrotron (SPS) is a particle accelerator at CERN. Originally specified as a 300 GeV machine, the SPS was actually built to be capable of 400GeV, an operating energy it achieved on the official commissioning date of 17 June 1976. ... Carlo Rubbia (born March 31, 1934) is an Italian physicist. ... Simon van der Meer (born November 24, 1925) is a Dutch physicist. ... The UA1 high energy physics experiment ran at CERN from 1981 until 1993 on the SPS collider. ... The UA2 high energy physics experiment was one of the two major experiments and collaborations at the CERN proton-antiproton collider, and codiscovered the W and Z bosons in 1983. ... In a storage ring the charged particles travel in bunches in potential hollows. ... The Nobel Prize (Swedish: ) was established in Alfred Nobels will in 1895, and it was first awarded in Physics, Chemistry, Physiology or Medicine, Literature, and Peace in 1901. ...


Decay

The W and Z bosons decay to fermion-antifermion pairs. Neglecting phase space effects and higher order corrections, simple estimates of their banching fractions can be calculated from the coupling constants.


W bosons can decay to a lepton and neutrino or to an up-type quark and a down-type quark. The W cannot decay to the higher-mass top quark. The decay width of the W boson to a quark-antiquark pair is proportional to the corresponding squared CKM matrix element and the number of quark colors, NC = 3. The decay widths for the W boson are then proportional to In the standard model of particle physics the Cabibbo Kobayashi Maskawa matrix (CKM matrix, sometimes earlier called KM matrix) is a unitary matrix which contains information on the strength of flavour changing weak decays. ...

e+νe 1
μ+νμ 1
τ+ντ 1
ud 3|Vud|2
us 3|Vus|2
ub 3|Vub|2
cd 3|Vcd|2
cs 3|Vcs|2
cb 3|Vcb|2

Unitarity of the CKM matrix implies that |Vud|2 + |Vus|2 + |Vub|2 = |Vcd|2 + |Vcs|2 + |Vcb|2 = 1. Therefore the leptonic branching ratios of the W boson are approximately B(e+νe) = B(μ+ντ) = B(τ+ντ) = 1/9. The hadronic branching ratio is dominated by the CKM favored ud and cs final states, and the sum of the hadronic branching ratios is roughly 2/3. The branching ratios have been measured experimentally: B(l+νl) = 10.80±0.09% and B(hadrons) = 67.60±0.27%.[1]


Z bosons can decay to a fermion and its antiparticle, with the exception of the top quark, which is too massive. The decay width of a Z boson to a fermion-antifermion pair is proportional to the square of the weak charge T3-Qx, where T3 is the third component of the weak isospin of the fermion, Q is the charge of the fermion, and x = sin2θW, where θW is the weak mixing angle. Because the weak isospin is different for left-handed and right-handed fermions, the coupling is different as well. The decay width of the Z boson for quarks is also proportional to NC. The weak charge of the fermions is:

e, νμ, ντ)L ½
(e, μ, τ)L -½+x
(e, μ, τ)R x
(u, c)L ½-⅔x
(d, s, b)L -½+⅓x
(u, c)R -⅔x
(d, s, b)R ⅓x

The decay widths of the Z boson are then proportional to

e, νμ, ντ) ½2
(e, μ, τ) (-½+x)2+x2
(u, c) 3(½-⅔x)2+3(-⅔x)2
(d, s, b) 3(-½+⅓x)2+3(⅓x)2

For x = 0.23, the branching ratios of the Z boson are predicted to be B(νν) = 20.5%, B(e+e-) = B(μ+μ-) = B(τ+τ-) = 3.4%, B(uu) = B(cc) = 11.8%, B(dd) = B(ss) = B(bb) = 15.2% and B(hadrons) = 69.2%. The branching ratios have been measured experimentally: B(l+l+) = 3.3658±0.0023%, B(νν) = 20.00±0.06%, B(hadrons) = 69.91±0.06%, B(uu + cc) = 11.6±0.6% and B(dd + ss + bb) = 15.6±0.4%.[2]


See also

This is a detailed description of the standard model (SM) of particle physics. ... This is a list of particles in particle physics, including currently known and hypothetical elementary particles, as well as the composite particles that can be built up from them. ... In particle physics, the X and Y bosons are hypothetical elementary particles analogous to the W and Z bosons, but corresponding to a new type of force, such as the forces predicted by grand unified theory. ... For the album, see Grand Unification (album). ... It has been suggested that this article or section be merged with Z boson. ... In particle physics, a Z boson (or Z-prime boson) refers to a hypothetical new neutral gauge boson (named in analogy with the Standard Model Z boson). ...

External links

CERN logo The European Organization for Nuclear Research (French: ), commonly known as CERN (see Naming), pronounced (or in French), is the worlds largest particle physics laboratory, situated just northwest of Geneva on the border between France and Switzerland. ... Thousands of particles explode from the collision point of two relativistic (100 GeV per nucleon) gold ions in the STAR detector of the Relativistic Heavy Ion Collider. ... For the novel, see The Elementary Particles. ... In particle physics, fermions are particles with half-integer spin, such as protons and electrons. ... For other uses, see Quark (disambiguation). ... The up quark is a first-generation quark with a charge of +(2/3)e. ... The down quark is a first-generation quark with a charge of -(1/3)e. ... The charm quark is a second-generation quark with a charge of +(2/3)e. ... The strange quark is a second-generation quark with a charge of -(1/3)e and a strangeness of −1. ... The top quark is the third-generation up-type quark with a charge of +(2/3)e. ... The bottom quark is a third-generation quark with a charge of -(1/3)e. ... For the former Greek currency unit, see Greek drachma. ... For other uses, see Electron (disambiguation). ... The first detection of the positron in 1932 by Carl D. Anderson The positron is the antiparticle or the antimatter counterpart of the electron. ... The muon (from the letter mu (μ)--used to represent it) is an elementary particle with negative electric charge and a spin of 1/2. ... The tau lepton (often called the tau, tau particle, or occasionally the tauon, symbol ) is a negatively charged elementary particle with a lifetime of 2. ... For other uses, see Neutrino (disambiguation). ... Antineutrinos, the antiparticles of neutrinos, are neutral particles produced in nuclear beta decay. ... In particle physics, bosons are particles with an integer spin, as opposed to fermions which have half-integer spin. ... Gauge bosons are bosonic particles which act as carriers of the fundamental forces of Nature. ... In modern physics the photon is the elementary particle responsible for electromagnetic phenomena. ... In particle physics, gluons are subatomic particles that cause quarks to interact, and are indirectly responsible for the binding of protons and neutrons together in atomic nuclei. ... In physics, Faddeev-Popov ghost ci is a field that violates the spin-statistics relation. ... In physics, a bound state is a composite of two or more building blocks (particles or bodies) that behaves as a single object. ... A hadron, in particle physics, is a subatomic particle which experiences the nuclear force. ... Combinations of three u, d or s-quarks with a total spin of 3/2 form the so-called baryon decuplet. ... In particle physics, a hyperon is any subatomic particle which is a baryon (and hence a hadron and a fermion) with non-zero strangeness, but with zero charm and zero bottomness. ... In physics a nucleon is a collective name for two baryons: the neutron and the proton. ... For other uses, see Proton (disambiguation). ... This article or section does not adequately cite its references or sources. ... The Delta baryon is a relatively light 1,232 MeV/c² baryon which contains only up (u) and down (d) quarks in a combination whose total spin is 3/2 and its ground state parity is +. All varieties of Δ quickly decay via the strong force into an ordinary nucleon plus... Properties In particle physics, the omega minus (Ω−) is a type of baryon (more specifically, a hyperon). ... Mesons of spin 1 form a nonet In particle physics, a meson is a strongly interacting boson, that is, it is a hadron with integral spin. ... In high energy physics, a quarkonium (pl. ... In particle physics, pion (short for pi meson) is the collective name for three subatomic particles: Ï€0, Ï€+ and π−. Pions are the lightest mesons and play an important role in explaining low-energy properties of the strong nuclear force. ... In particle physics, Kaons (also called K-mesons and denoted K) are a group of four mesons distinguished by the fact that they carry a quantum number called strangeness. ... In particle physics, a rho meson is a short-lived hadronic particle that is an isospin triplet whose three states are denoted as , and . ... The upsilon particle () is a flavorless meson formed from a bottom quark and its antiparticle. ... The nucleus of an atom is the very small dense region, of positive charge, in its centre consisting of nucleons (protons and neutrons). ... For other uses, see Atom (disambiguation). ... An exotic atom is the anologue of a normal atom in which one or more of the electrons are replaced by other negative particles, such as a muon or a pion, or the positively charged nucleus is replaced by other positively charged elementary particles, or both. ... Positronium (Ps) is a system consisting of an electron and its anti-particle, a positron, bound together into an exotic atom. The orbit of the two particles and the set of energy levels is similar to that of the hydrogen atom (electron and proton). ... A muonium particle is an exotic atom made up of a positive muon and an electron, and is given the symbol Mu or μ+e–. During the muons 2 microsecond lifetime, muonium can enter into compounds such as muonium chloride (MuCl) or sodium muonide (NaMu). ... 3D (left and center) and 2D (right) representations of the terpenoid molecule atisane. ... This is a list of particles in particle physics, including currently known and hypothetical elementary particles, as well as the composite particles that can be built up from them. ... In supersymmetry, it is proposed that every fermion should have a partner boson, known as its Superpartner. ... The axino is a hypothetical elementary particle predicted by some theories of particle physics. ... In particle physics, chargino refers to a charged superpartner, i. ... In particle physics, a gaugino is the hypothetical superpartner of a gauge boson, as predicted by gauge theory combined with supersymmetry. ... A gluino is a subatomic particle, the fermion superpartner of the gluon predicted by supersymmetry. ... The gravitino is the hypothetical supersymmetric partner of the graviton, as predicted by theories combining general relativity and supersymmetry, i. ... In particle physics, a higgsino is the hypothetical superpartner of the Higgs boson, as predicted by supersymmetry. ... In particle physics, the neutralino is a hypothetical particle and part of the doubling of the menagerie of particles predicted by supersymmetric theories. ... In particle physics, a sfermion is any of the class of spin-0 superpartners of ordinary fermions appearing in supersymmetric extensions to the Standard Model. ... The axion is an exotic subatomic particle postulated by Peccei-Quinn theory to resolve the strong-CP problem in quantum chromodynamics (QCD). ... In theoretical physics, dilaton originally referred to a theoretical scalar field; as a photon refers in one sense to the electromagnetic field. ... This article is about the hypothetical particle. ... The Higgs boson, also known as the God particle, is a hypothetical massive scalar elementary particle predicted to exist by the Standard Model of particle physics. ... This box:      A tachyon (from the Greek , takhyónion, from , takhýs, i. ... In particle physics, the X and Y bosons are hypothetical elementary particles analogous to the W and Z bosons, but corresponding to a new type of force, such as the forces predicted by grand unified theory. ... It has been suggested that this article or section be merged with Z boson. ... In particle physics, a Z boson (or Z-prime boson) refers to a hypothetical new neutral gauge boson (named in analogy with the Standard Model Z boson). ... A sterile particle does not have any charge known to us. ... A regular meson made from a quark (q) and antiquark (q-bar) with spins s2 and s1 respectively and having an overall angular momentum L Exotic hadrons are subatomic particles made of quarks (and possibly gluons), but which do not fit into the usual schema of hadrons. ... Ordinary baryons are bound states of 3 quarks. ... A pentaquark is a subatomic particle consisting of a group of five quarks (compared to three quarks in normal baryons and two in mesons), or more specifically four quarks and one anti-quark. ... Identities and classification of possible tetraquark mesons. ... In particle physics, a glueball is a particle containing no valence quarks. ... A tetraquark is a subatomic particle composed of four quarks. ... A mesonic molecule is a set of two or more mesons bound together by the strong force. ... In physics, a quasiparticle refers to a particle-like entity arising in certain systems of interacting particles. ... Side view of an α-helix of alanine residues in atomic detail. ... This page is about the quasiparticle. ... There is a place named Magnon (pronunciation: ma-nyon) in Gabon, see Magnon, Gabon A magnon is a collective excitation of the electrons spin structure in a crystal lattice. ... Normal modes of vibration progression through a crystal. ... In physics, the plasmon is the quasiparticle resulting from the quantization of plasma oscillations just as photons and phonons are quantizations of light and sound waves, respectively. ... This article is in need of attention. ... In solid-state physics, a polaron is formed when a moving charge (typically an electron or a hole) in a crystal with some ionic character polarizes (by its electric field) the lattice around it. ... This is a list of particles in particle physics, including currently known and hypothetical elementary particles, as well as the composite particles that can be built up from them. ... Baryon decuplet: Spin=3/2 Baryon octet: Spin=1/2 This is a list of baryons. ... A list of mesons. ... Timeline of subatomic particle discoveries. ...

  Results from FactBites:
 
Theory: Weak Interaction Carrier Particles (SLAC VVC) (268 words)
Because the mass of the Z is large compared to the mass of the photon in most low energy situations the effects of Z-exchanges are tiny compared to photon exchanges.
Z bosons produced by colliding electron and positron beams with just the right energy to make a single Z are the main object of study for the linear collider at SLAC.
Z bosons decay to produce either quark and its matching flavor antiquark or a lepton and its matching anti-lepton.
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