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82-790: The Global Design Effort (GDE) was an international team tasked with designing the International Linear Collider (ILC), a particle accelerator to succeed machines such as the Large Hadron Collider (LHC) and the Stanford Linear Accelerator (SLAC), with the endorsement of the International Committee for Future Accelerators. Between 2005–2013, the GDE led planning, research and development, and produced an ILC Technical Design Report. The Global Design Effort

164-498: A G a μ ν , {\displaystyle {\mathcal {L}}_{\text{QCD}}={\overline {\psi }}i\gamma ^{\mu }D_{\mu }\psi -{\frac {1}{4}}G_{\mu \nu }^{a}G_{a}^{\mu \nu },} where ψ {\displaystyle \psi } is a three component column vector of Dirac spinors , each element of which refers to a quark field with a specific color charge (i.e. red, blue, and green) and summation over flavor (i.e. up, down, strange, etc.)

246-614: A μ ν W μ ν a − 1 4 B μ ν B μ ν , {\displaystyle {\mathcal {L}}_{\text{EW}}={\overline {Q}}_{Lj}i\gamma ^{\mu }D_{\mu }Q_{Lj}+{\overline {u}}_{Rj}i\gamma ^{\mu }D_{\mu }u_{Rj}+{\overline {d}}_{Rj}i\gamma ^{\mu }D_{\mu }d_{Rj}+{\overline {\ell }}_{Lj}i\gamma ^{\mu }D_{\mu }\ell _{Lj}+{\overline {e}}_{Rj}i\gamma ^{\mu }D_{\mu }e_{Rj}-{\tfrac {1}{4}}W_{a}^{\mu \nu }W_{\mu \nu }^{a}-{\tfrac {1}{4}}B^{\mu \nu }B_{\mu \nu },} where

328-560: A complete theory of fundamental interactions . For example, it does not fully explain why there is more matter than anti-matter , incorporate the full theory of gravitation as described by general relativity , or account for the universe's accelerating expansion as possibly described by dark energy . The model does not contain any viable dark matter particle that possesses all of the required properties deduced from observational cosmology . It also does not incorporate neutrino oscillations and their non-zero masses. The development of

410-466: A $ 20 billion total. Upon completion of the 2013 ILC Design Report, Barish said the cost of building the ILC was the equivalent of 7.78 billion 2012 U.S. dollars; it will require "22.6 million hours of labor and location-specific costs including site preparation, scientific detectors and facility operations." Standard Model The Standard Model of particle physics is the theory describing three of

492-433: A 370-meter linac stage. Synchrotron radiation from high energy electrons will produce electron-positron pairs on a titanium-alloy target, with as much as 60% polarization; the positrons from these collisions will be collected and accelerated to 5 GeV in a separate linac. To compact the 5 GeV electron and positron bunches to a sufficiently small size to be usefully collided, they will circulate for 0.1–0.2 seconds in

574-534: A circular design, particles can be effectively accelerated over longer distances. Also, only a fraction of the particles brought onto a collision course actually collide. In a linear accelerator, the remaining particles are lost; in a ring accelerator, they keep circulating and are available for future collisions. The disadvantage of circular accelerators is that charged particles moving along bent paths will necessarily emit electromagnetic radiation known as synchrotron radiation . Energy loss through synchrotron radiation

656-438: A graphical representation of the perturbation theory approximation, invoke "force mediating particles", and when applied to analyze high-energy scattering experiments are in reasonable agreement with the data. However, perturbation theory (and with it the concept of a "force-mediating particle") fails in other situations. These include low-energy quantum chromodynamics, bound states , and solitons . The interactions between all

738-670: A machine of length similar to the ILC. These two projects, CLIC and the ILC, have been unified under the Linear Collider Collaboration . There are two basic shapes of accelerators. Linear accelerators ("linacs") accelerate elementary particles along a straight path. Circular accelerators ("synchrotrons"), such as the Tevatron , the LEP , and the Large Hadron Collider (LHC), use circular paths. Circular geometry has significant advantages at energies up to and including tens of GeV : With

820-1043: A member of the group SU(3), and ϕ a ( x ) {\displaystyle \phi ^{a}(x)} is an arbitrary function of spacetime. The electroweak sector is a Yang–Mills gauge theory with the symmetry group U(1) × SU(2) L , L EW = Q ¯ L j i γ μ D μ Q L j + u ¯ R j i γ μ D μ u R j + d ¯ R j i γ μ D μ d R j + ℓ ¯ L j i γ μ D μ ℓ L j + e ¯ R j i γ μ D μ e R j − 1 4 W

902-535: A new particle with a mass of about 125  GeV/ c (about 133 proton masses, on the order of 10  kg ), which is "consistent with the Higgs boson". On 13 March 2013, it was confirmed to be the searched-for Higgs boson. Technically, quantum field theory provides the mathematical framework for the Standard Model, in which a Lagrangian controls the dynamics and kinematics of the theory. Each kind of particle

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984-459: A non-zero Vacuum expectation value , which generates masses for the Electroweak gauge fields (the Higgs' mechanism), and λ > 0 {\displaystyle \lambda >0} , so that the potential is bounded from below. The quartic term describes self-interactions of the scalar field φ {\displaystyle \varphi } . The minimum of the potential

1066-542: A pair of damping rings, 3.24 km in circumference, in which they will be reduced in size to 6 mm in length and a vertical and horizontal emittance of 2 pm and 0.6 nm, respectively. From the damping rings the particle bunches will be sent to the superconducting radio frequency main linacs, each 11 km long, where they will be accelerated to 250 GeV. At this energy each beam will have an average power of about 5.3 megawatts . Five bunch trains will be produced and accelerated per second. To maintain

1148-611: A sufficient luminosity to produce results in a reasonable time frame after acceleration the bunches will be focused to a few nanometers in height and a few hundred nanometers in width. The focused bunches then will be collided inside one of two large particle detectors . Originally, three sites for the International Linear Collider were leading contenders at established High Energy Physics centers in Europe. At CERN in Geneva

1230-464: Is conventionally called a " positron ". The Standard Model includes 12 elementary particles of spin 1 ⁄ 2 , known as fermions . Fermions respect the Pauli exclusion principle , meaning that two identical fermions cannot simultaneously occupy the same quantum state in the same atom. Each fermion has a corresponding antiparticle , which are particles that have corresponding properties with

1312-431: Is degenerate with an infinite number of equivalent ground state solutions, which occurs when φ † φ = μ 2 2 λ {\displaystyle \varphi ^{\dagger }\varphi ={\tfrac {\mu ^{2}}{2\lambda }}} . It is possible to perform a gauge transformation on φ {\displaystyle \varphi } such that

1394-412: Is described in terms of a dynamical field that pervades space-time . The construction of the Standard Model proceeds following the modern method of constructing most field theories: by first postulating a set of symmetries of the system, and then by writing down the most general renormalizable Lagrangian from its particle (field) content that observes these symmetries. The global Poincaré symmetry

1476-477: Is implied. The gauge covariant derivative of QCD is defined by D μ ≡ ∂ μ − i g s 1 2 λ a G μ a {\displaystyle D_{\mu }\equiv \partial _{\mu }-ig_{s}{\frac {1}{2}}\lambda ^{a}G_{\mu }^{a}} , where The QCD Lagrangian is invariant under local SU(3) gauge transformations; i.e., transformations of

1558-503: Is inversely proportional to the fourth power of the mass of the particles in question. That is why it makes sense to build circular accelerators for heavy particles—hadron colliders such as the LHC for protons or, alternatively, for lead nuclei . An electron–positron collider of the same size would never be able to achieve the same collision energies. In fact, energies at the LEP which used to occupy

1640-405: Is mediated by mesons, such as the pion . The color charges inside the nucleon cancel out, meaning most of the gluon and quark fields cancel out outside of the nucleon. However, some residue is "leaked", which appears as the exchange of virtual mesons, that causes the attractive force between nucleons. The (fundamental) strong interaction is described by quantum chromodynamics, which is a component of

1722-404: Is postulated for all relativistic quantum field theories. It consists of the familiar translational symmetry , rotational symmetry and the inertial reference frame invariance central to the theory of special relativity . The local SU(3)×SU(2)×U(1) gauge symmetry is an internal symmetry that essentially defines the Standard Model. Roughly, the three factors of the gauge symmetry give rise to

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1804-558: Is the Higgs doublet and φ ~ = i τ 2 φ ∗ {\displaystyle {\tilde {\varphi }}=i\tau _{2}\varphi ^{*}} is its charge conjugate state. The Yukawa terms are invariant under the SU ⁡ ( 2 ) L × U ⁡ ( 1 ) Y {\displaystyle \operatorname {SU} (2)_{\text{L}}\times \operatorname {U} (1)_{\text{Y}}} gauge symmetry of

1886-467: Is the electroweak gauge covariant derivative defined above and V ( φ ) {\displaystyle V(\varphi )} is the potential of the Higgs field. The square of the covariant derivative leads to three and four point interactions between the electroweak gauge fields W μ a {\displaystyle W_{\mu }^{a}} and B μ {\displaystyle B_{\mu }} and

1968-469: Is the only long-range force in the Standard Model. It is mediated by photons and couples to electric charge. Electromagnetism is responsible for a wide range of phenomena including atomic electron shell structure , chemical bonds , electric circuits and electronics . Electromagnetic interactions in the Standard Model are described by quantum electrodynamics. The weak interaction is responsible for various forms of particle decay , such as beta decay . It

2050-424: Is weak and short-range, due to the fact that the weak mediating particles, W and Z bosons, have mass. W bosons have electric charge and mediate interactions that change the particle type (referred to as flavour) and charge. Interactions mediated by W bosons are charged current interactions . Z bosons are neutral and mediate neutral current interactions, which do not change particle flavour. Thus Z bosons are similar to

2132-488: The Future Circular Collider , which has overlapping physics goals with the ILC. In March 2024, the "Federation of Diet Members for the ILC" met to receive "Reports on the ILC project's progress and initiatives by relevant organizations". Fifty participants, including Diet members and other government agencies, as well as researchers and businesses, received reports on the project's progress. Participants discussed

2214-553: The GIM mechanism , predicting the charm quark . In 1973 Gross and Wilczek and Politzer independently discovered that non-Abelian gauge theories, like the color theory of the strong force, have asymptotic freedom . In 1976, Martin Perl discovered the tau lepton at the SLAC . In 1977, a team led by Leon Lederman at Fermilab discovered the bottom quark. The Higgs mechanism is believed to give rise to

2296-647: The T2K experiment , a factor not in its favor, although 20 huge caverns with access tunnels have already been constructed in Japan for hydroelectric power plants (e.g. the Kannagawa Hydropower Plant ). Following the closure of the Tevatron some groups within the USA had expressed interest, with Fermilab being a favored site because of the facilities and experts already present. Much of the speculated interest from other countries

2378-471: The atomic nucleus , ultimately constituted of up and down quarks. On the other hand, second- and third-generation charged particles decay with very short half-lives and can only be observed in high-energy environments. Neutrinos of all generations also do not decay, and pervade the universe, but rarely interact with baryonic matter. There are six quarks: up , down , charm , strange , top , and bottom . Quarks carry color charge , and hence interact via

2460-628: The electron , electron neutrino , muon , muon neutrino , tau , and tau neutrino . The leptons do not carry color charge, and do not respond to strong interaction. The main leptons carry an electric charge of -1 e , while the three neutrinos carry a neutral electric charge. Thus, the neutrinos' motion are only influenced by weak interaction and gravity , making them difficult to observe. The Standard Model includes 4 kinds of gauge bosons of spin 1, with bosons being quantum particles containing an integer spin. The gauge bosons are defined as force carriers , as they are responsible for mediating

2542-562: The fundamental interactions . The Standard Model explains the four fundamental forces as arising from the interactions, with fermions exchanging virtual force carrier particles, thus mediating the forces. At a macroscopic scale, this manifests as a force . As a result, they do not follow the Pauli exclusion principle that constrains fermions; bosons do not have a theoretical limit on their spatial density . The types of gauge bosons are described below. The Feynman diagram calculations, which are

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2624-549: The masses of all the elementary particles in the Standard Model. This includes the masses of the W and Z bosons , and the masses of the fermions , i.e. the quarks and leptons . After the neutral weak currents caused by Z boson exchange were discovered at CERN in 1973, the electroweak theory became widely accepted and Glashow, Salam, and Weinberg shared the 1979 Nobel Prize in Physics for discovering it. The W and Z bosons were discovered experimentally in 1983; and

2706-651: The mn term giving the coupling of the generations m and n , and h.c. means Hermitian conjugate of preceding terms. The fields Q L {\displaystyle Q_{\text{L}}} and ℓ L {\displaystyle \ell _{\text{L}}} are left-handed quark and lepton doublets. Likewise, u R , d R {\displaystyle u_{\text{R}},d_{\text{R}}} and e R {\displaystyle e_{\text{R}}} are right-handed up-type quark, down-type quark, and lepton singlets. Finally φ {\displaystyle \varphi }

2788-585: The strong interaction . The color confinement phenomenon results in quarks being strongly bound together such that they form color-neutral composite particles called hadrons ; quarks cannot individually exist and must always bind with other quarks. Hadrons can contain either a quark-antiquark pair ( mesons ) or three quarks ( baryons ). The lightest baryons are the nucleons : the proton and neutron . Quarks also carry electric charge and weak isospin , and thus interact with other fermions through electromagnetism and weak interaction . The six leptons consist of

2870-558: The 50 GeV Stanford Linear Accelerator , the longest existing linear particle accelerator. The proposal is based on previous similar proposals from Europe, the U.S., and Japan. In a staged approach, the ILC could initially be constructed at 250 GeV, for use as a Higgs factory . Such a design would be approximately 20 km in length. Studies for an alternative project, the Compact Linear Collider (CLIC) are also underway, which would operate at higher energies (up to 3 TeV) in

2952-476: The Higgs boson is massive, it must interact with itself. Because the Higgs boson is a very massive particle and also decays almost immediately when created, only a very high-energy particle accelerator can observe and record it. Experiments to confirm and determine the nature of the Higgs boson using the Large Hadron Collider (LHC) at CERN began in early 2010 and were performed at Fermilab 's Tevatron until its closure in late 2011. Mathematical consistency of

3034-1333: The Higgs' mass could not be predicted beforehand and had to be determined experimentally. The Yukawa interaction terms are: L Yukawa = ( Y u ) m n ( Q ¯ L ) m φ ~ ( u R ) n + ( Y d ) m n ( Q ¯ L ) m φ ( d R ) n + ( Y e ) m n ( ℓ ¯ L ) m φ ( e R ) n + h . c . {\displaystyle {\mathcal {L}}_{\text{Yukawa}}=(Y_{\text{u}})_{mn}({\bar {Q}}_{\text{L}})_{m}{\tilde {\varphi }}(u_{\text{R}})_{n}+(Y_{\text{d}})_{mn}({\bar {Q}}_{\text{L}})_{m}\varphi (d_{\text{R}})_{n}+(Y_{\text{e}})_{mn}({\bar {\ell }}_{\text{L}})_{m}{\varphi }(e_{\text{R}})_{n}+\mathrm {h.c.} } where Y u {\displaystyle Y_{\text{u}}} , Y d {\displaystyle Y_{\text{d}}} , and Y e {\displaystyle Y_{\text{e}}} are 3 × 3 matrices of Yukawa couplings, with

3116-473: The ILC's future. The meeting resulted in three recommendations: 1. The ILC project will be further promoted by the research community, industry, organizations promoting the candidate sites, relevant ministries and agencies, the Diet members and other political organizations within an all-Japan framework. 2. For the ILC project, international collaboration will be further strengthened as a global initiative involving

3198-631: The International Linear Collider. On August 23, 2013, the Japanese high-energy physics community's site evaluation committee proposed it should be located in the Kitakami Mountains of the Iwate and Miyagi Prefectures . As of March 7, 2019, the Japanese government has stated that it is not ready to support the construction of the Collider due to its high proposed cost of approximately $ 7 billion. This decision

3280-778: The Next Linear Collider (NLC), the Global Linear Collider (GLC) and Teraelectronvolt Energy Superconducting Linear Accelerator (TESLA) – joined their efforts into one single project (the ILC). In March 2005, the International Committee for Future Accelerators (ICFA) announced Prof. Barry Barish , director of the LIGO Laboratory at Caltech from 1997 to 2005, as the Director of the Global Design Effort (GDE). In August 2007,

3362-512: The Reference Design Report for the ILC was released. Physicists working on the GDE completed a detailed ILC design report, publishing it in June 2013. The electron source for the ILC will use 2-nanosecond laser light pulses to eject electrons from a photocathode , a technique allowing for up to 80% of the electrons to be polarized; the electrons then will be accelerated to 5 GeV in

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3444-510: The Standard Model and generate masses for all fermions after spontaneous symmetry breaking. The Standard Model describes three of the four fundamental interactions in nature; only gravity remains unexplained. In the Standard Model, such an interaction is described as an exchange of bosons between the objects affected, such as a photon for the electromagnetic force and a gluon for the strong interaction. Those particles are called force carriers or messenger particles . Despite being perhaps

3526-489: The Standard Model are expected to be discovered and measured. At the ILC physicists hope to be able to: To achieve these goals, new generation particle detectors are necessary. In August 2004, the International Technology Recommendation Panel (ITRP) recommended a superconducting radio frequency technology for the accelerator. After this decision the three existing linear collider projects –

3608-430: The Standard Model requires that any mechanism capable of generating the masses of elementary particles must become visible at energies above 1.4  TeV ; therefore, the LHC (designed to collide two 7 TeV proton beams) was built to answer the question of whether the Higgs boson actually exists. On 4 July 2012, two of the experiments at the LHC ( ATLAS and CMS ) both reported independently that they had found

3690-510: The Standard Model was driven by theoretical and experimental particle physicists alike. The Standard Model is a paradigm of a quantum field theory for theorists, exhibiting a wide range of phenomena, including spontaneous symmetry breaking , anomalies , and non-perturbative behavior. It is used as a basis for building more exotic models that incorporate hypothetical particles , extra dimensions , and elaborate symmetries (such as supersymmetry ) to explain experimental results at variance with

3772-496: The Standard Model, such as the existence of dark matter and neutrino oscillations. In 1928, Paul Dirac introduced the Dirac equation which implied the existence of antimatter . In 1954, Yang Chen-Ning and Robert Mills extended the concept of gauge theory for abelian groups , e.g. quantum electrodynamics , to nonabelian groups to provide an explanation for strong interactions . In 1957, Chien-Shiung Wu demonstrated parity

3854-432: The accelerator complex and detectors is expected to require seven years. The host country would be required to pay $ 1.8 billion for site-specific costs like digging tunnels and shafts and supplying water and electricity. Former U.S. Secretary of Energy Steven Chu estimated the total cost to be US$ 25 billion. ILC Director Barish said this is likely to be an overestimate. Other Department of Energy officials have estimated

3936-462: The addition of fermion mass terms into the electroweak Lagrangian is forbidden, since terms of the form m ψ ¯ ψ {\displaystyle m{\overline {\psi }}\psi } do not respect U(1) × SU(2) L gauge invariance. Neither is it possible to add explicit mass terms for the U(1) and SU(2) gauge fields. The Higgs mechanism is responsible for the generation of

4018-447: The energy is distributed among the constituent quarks , antiquarks and gluons of baryonic particles. As such, one of the roles of the ILC would be making precision measurements of the properties of particles discovered at the LHC. It is widely expected that effects of physics beyond that described in the current Standard Model will be detected by experiments at the proposed ILC. In addition, particles and interactions described by

4100-626: The exception of opposite charges . Fermions are classified based on how they interact, which is determined by the charges they carry, into two groups: quarks and leptons . Within each group, pairs of particles that exhibit similar physical behaviors are then grouped into generations (see the table). Each member of a generation has a greater mass than the corresponding particle of generations prior. Thus, there are three generations of quarks and leptons. As first-generation particles do not decay, they comprise all of ordinary ( baryonic ) matter. Specifically, all atoms consist of electrons orbiting around

4182-593: The existence of quarks . Since then, proof of the top quark (1995), the tau neutrino (2000), and the Higgs boson (2012) have added further credence to the Standard Model. In addition, the Standard Model has predicted various properties of weak neutral currents and the W and Z bosons with great accuracy. Although the Standard Model is believed to be theoretically self-consistent and has demonstrated some success in providing experimental predictions , it leaves some physical phenomena unexplained and so falls short of being

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4264-486: The form ψ → ψ ′ = U ψ {\displaystyle \psi \rightarrow \psi '=U\psi } , where U = e − i g s λ a ϕ a ( x ) {\displaystyle U=e^{-ig_{s}\lambda ^{a}\phi ^{a}(x)}} is 3 × 3 {\displaystyle 3\times 3} unitary matrix with determinant 1, making it

4346-400: The four known fundamental forces ( electromagnetic , weak and strong interactions – excluding gravity ) in the universe and classifying all known elementary particles . It was developed in stages throughout the latter half of the 20th century, through the work of many scientists worldwide, with the current formulation being finalized in the mid-1970s upon experimental confirmation of

4428-862: The gauge boson masses, and the fermion masses result from Yukawa-type interactions with the Higgs field. In the Standard Model, the Higgs field is an SU ⁡ ( 2 ) L {\displaystyle \operatorname {SU} (2)_{\text{L}}} doublet of complex scalar fields with four degrees of freedom: φ = ( φ + φ 0 ) = 1 2 ( φ 1 + i φ 2 φ 3 + i φ 4 ) , {\displaystyle \varphi ={\begin{pmatrix}\varphi ^{+}\\\varphi ^{0}\end{pmatrix}}={\frac {1}{\sqrt {2}}}{\begin{pmatrix}\varphi _{1}+i\varphi _{2}\\\varphi _{3}+i\varphi _{4}\end{pmatrix}},} where

4510-626: The global accelerator program. This collaboration should utilize the framework of the Liaison Committee on Future High-Performance Accelerators, in partnership with the Cabinet Office, as well as other relevant ministries and agencies. The Reference Design Report estimated the cost of building the ILC, excluding R&D, prototyping, land acquisition, underground easement costs, detectors, contingencies, and inflation, at US$ 6.75 billion (in 2007 prices). From formal project approval, completion of

4592-428: The ground state is transformed to a basis where φ 1 = φ 2 = φ 4 = 0 {\displaystyle \varphi _{1}=\varphi _{2}=\varphi _{4}=0} and φ 3 = μ λ ≡ v {\displaystyle \varphi _{3}={\tfrac {\mu }{\sqrt {\lambda }}}\equiv v} . This breaks

4674-614: The interactions between quarks and gluons, which is a Yang–Mills gauge theory with SU(3) symmetry, generated by T a = λ a / 2 {\displaystyle T^{a}=\lambda ^{a}/2} . Since leptons do not interact with gluons, they are not affected by this sector. The Dirac Lagrangian of the quarks coupled to the gluon fields is given by L QCD = ψ ¯ i γ μ D μ ψ − 1 4 G μ ν

4756-642: The left-handed doublet and right-handed singlet lepton fields. The electroweak gauge covariant derivative is defined as D μ ≡ ∂ μ − i g ′ 1 2 Y W B μ − i g 1 2 τ → L W → μ {\displaystyle D_{\mu }\equiv \partial _{\mu }-ig'{\tfrac {1}{2}}Y_{\text{W}}B_{\mu }-ig{\tfrac {1}{2}}{\vec {\tau }}_{\text{L}}{\vec {W}}_{\mu }} , where Notice that

4838-408: The massive spin-zero particle, was proposed as the Higgs boson , and is a key building block in the Standard Model. It has no intrinsic spin , and for that reason is classified as a boson with spin-0. The Higgs boson plays a unique role in the Standard Model, by explaining why the other elementary particles, except the photon and gluon , are massive. In particular, the Higgs boson explains why

4920-415: The most familiar fundamental interaction, gravity is not described by the Standard Model, due to contradictions that arise when combining general relativity, the modern theory of gravity, and quantum mechanics. However, gravity is so weak at microscopic scales, that it is essentially unmeasurable. The graviton is postulated to be the mediating particle, but has not yet been proved to exist. Electromagnetism

5002-427: The particles described by the Standard Model are summarized by the diagrams on the right of this section. The Higgs particle is a massive scalar elementary particle theorized by Peter Higgs ( and others ) in 1964, when he showed that Goldstone's 1962 theorem (generic continuous symmetry, which is spontaneously broken) provides a third polarisation of a massive vector field. Hence, Goldstone's original scalar doublet,

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5084-431: The photon has no mass, while the W and Z bosons are very heavy. Elementary-particle masses and the differences between electromagnetism (mediated by the photon) and the weak force (mediated by the W and Z bosons) are critical to many aspects of the structure of microscopic (and hence macroscopic) matter. In electroweak theory , the Higgs boson generates the masses of the leptons (electron, muon, and tau) and quarks. As

5166-423: The photon, aside from them being massive and interacting with the neutrino. The weak interaction is also the only interaction to violate parity and CP . Parity violation is maximal for charged current interactions, since the W boson interacts exclusively with left-handed fermions and right-handed antifermions. In the Standard Model, the weak force is understood in terms of the electroweak theory, which states that

5248-450: The ratio of their masses was found to be as the Standard Model predicted. The theory of the strong interaction (i.e. quantum chromodynamics , QCD), to which many contributed, acquired its modern form in 1973–74 when asymptotic freedom was proposed (a development which made QCD the main focus of theoretical research) and experiments confirmed that the hadrons were composed of fractionally charged quarks. The term "Standard Model"

5330-481: The research community. This will be achieved through close cooperation between the ILC International Development Team (IDT), an international promotion organization established under ICFA, and the domestic research community. 3. The Ministry of Education, Culture, Sports, Science and Technology (MEXT) should play an active role in collaborating with the international research community to achieve

5412-649: The scalar field φ {\displaystyle \varphi } . The scalar potential is given by V ( φ ) = − μ 2 φ † φ + λ ( φ † φ ) 2 , {\displaystyle V(\varphi )=-\mu ^{2}\varphi ^{\dagger }\varphi +\lambda \left(\varphi ^{\dagger }\varphi \right)^{2},} where μ 2 > 0 {\displaystyle \mu ^{2}>0} , so that φ {\displaystyle \varphi } acquires

5494-689: The scale of electroweak physics. This is the only dimensional parameter of the Standard Model and has a measured value of ~ 246 GeV/ c . After symmetry breaking, the masses of the W {\displaystyle {\text{W}}} and Z {\displaystyle {\text{Z}}} are given by m W = 1 2 g v {\displaystyle m_{\text{W}}={\frac {1}{2}}gv} and m Z = 1 2 g 2 + g ′ 2 v {\displaystyle m_{\text{Z}}={\frac {1}{2}}{\sqrt {g^{2}+g'^{2}}}v} , which can be viewed as predictions of

5576-430: The strong force becomes weaker, as the energy scale increases. The strong force overpowers the electrostatic repulsion of protons and quarks in nuclei and hadrons respectively, at their respective scales. While quarks are bound in hadrons by the fundamental strong interaction, which is mediated by gluons, nucleons are bound by an emergent phenomenon termed the residual strong force or nuclear force . This interaction

5658-522: The subscript j {\displaystyle j} sums over the three generations of fermions; Q L , u R {\displaystyle Q_{L},u_{R}} , and d R {\displaystyle d_{R}} are the left-handed doublet, right-handed singlet up type, and right handed singlet down type quark fields; and ℓ L {\displaystyle \ell _{L}} and e R {\displaystyle e_{R}} are

5740-774: The superscripts + and 0 indicate the electric charge Q {\displaystyle Q} of the components. The weak hypercharge Y W {\displaystyle Y_{\text{W}}} of both components is 1. Before symmetry breaking, the Higgs Lagrangian is L H = ( D μ φ ) † ( D μ φ ) − V ( φ ) , {\displaystyle {\mathcal {L}}_{\text{H}}=\left(D_{\mu }\varphi \right)^{\dagger }\left(D^{\mu }\varphi \right)-V(\varphi ),} where D μ {\displaystyle D_{\mu }}

5822-409: The surface in non-permeable soil. Dubna has a pre-accelerator complex which could have been easily adapted for the needs for the ILC. But all three were more or less well suited for housing a Linear Collider and one had ample choice for a site selection process in Europe. Outside Europe a number of countries expressed interest. Japan receives a large amount of funding for neutrino activities, such as

5904-451: The symmetry of the ground state. The expectation value of φ {\displaystyle \varphi } now becomes ⟨ φ ⟩ = 1 2 ( 0 v ) , {\displaystyle \langle \varphi \rangle ={\frac {1}{\sqrt {2}}}{\begin{pmatrix}0\\v\end{pmatrix}},} where v {\displaystyle v} has units of mass and sets

5986-467: The theory. The photon remains massless. The mass of the Higgs Boson is m H = 2 μ 2 = 2 λ v {\displaystyle m_{\text{H}}={\sqrt {2\mu ^{2}}}={\sqrt {2\lambda }}v} . Since μ {\displaystyle \mu } and λ {\displaystyle \lambda } are free parameters,

6068-434: The three fundamental interactions. The fields fall into different representations of the various symmetry groups of the Standard Model (see table). Upon writing the most general Lagrangian, one finds that the dynamics depends on 19 parameters, whose numerical values are established by experiment. The parameters are summarized in the table (made visible by clicking "show") above. The quantum chromodynamics (QCD) sector defines

6150-549: The tunnel is located deep underground in non-permeable bedrock. This site was considered favorable for a number of practical reasons but due to the LHC the site was disfavored. At DESY in Hamburg the tunnel is close to the surface in water saturated soil. Germany leads Europe for scientific funding and was therefore considered reliable in terms of funding. At JINR in Dubna the tunnel is close to

6232-417: The tunnel now given over to the LHC, were limited to 209 GeV by energy loss via synchrotron radiation. Even though the nominal collision energy at the LHC will be higher than the ILC collision energy (14,000  GeV for the LHC vs. ~500 GeV for the ILC), measurements could be made more accurately at the ILC. Collisions between electrons and positrons are much simpler to analyze than collisions in which

6314-546: The weak and electromagnetic interactions become united into a single electroweak interaction at high energies. The strong nuclear force is responsible for hadronic and nuclear binding . It is mediated by gluons, which couple to color charge. Since gluons themselves have color charge, the strong force exhibits confinement and asymptotic freedom . Confinement means that only color-neutral particles can exist in isolation, therefore quarks can only exist in hadrons and never in isolation, at low energies. Asymptotic freedom means that

6396-520: Was headed by Barry Barish of Caltech , former director of the LIGO laboratory. This particle physics –related article is a stub . You can help Misplaced Pages by expanding it . This accelerator physics -related article is a stub . You can help Misplaced Pages by expanding it . International Linear Collider The ILC would collide electrons with positrons . It will be between 30 km and 50 km (19–31 mi) long, more than 10 times as long as

6478-537: Was hearsay from within the scientific community, and very few facts were published officially. The information presented above is a summary of that contained in the International Workshop on Linear Colliders 2010 (ECFA-CLIC-ILC Joint Meeting) at CERN. The 2008 economic crisis led the United States and United Kingdom to cut funds to the collider project, leading to Japan's position as the most likely host for

6560-516: Was informed partly by the Science Council of Japan . The Japanese government sought monetary support from other countries to help fund this project. In 2022, the Japanese plan for the ILC was "shelved" by a panel for Japan’s Ministry of Education, Culture, Sports, Science and Technology (MEXT) Several reasons were given, including potentially insufficient international support and the CERN proposal for

6642-697: Was introduced by Abraham Pais and Sam Treiman in 1975, with reference to the electroweak theory with four quarks. Steven Weinberg , has since claimed priority, explaining that he chose the term Standard Model out of a sense of modesty and used it in 1973 during a talk in Aix-en-Provence in France. The Standard Model includes members of several classes of elementary particles, which in turn can be distinguished by other characteristics, such as color charge . All particles can be summarized as follows: Notes : [†] An anti-electron ( e )

6724-508: Was not conserved in the weak interaction . In 1961, Sheldon Glashow combined the electromagnetic and weak interactions . In 1964, Murray Gell-Mann and George Zweig introduced quarks and that same year Oscar W. Greenberg implicitly introduced color charge of quarks. In 1967 Steven Weinberg and Abdus Salam incorporated the Higgs mechanism into Glashow's electroweak interaction , giving it its modern form. In 1970, Sheldon Glashow, John Iliopoulos, and Luciano Maiani introduced

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