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102-733: The Letter of Intent for International Axion Observatory was submitted to the CERN in August 2013. IAXO formally founded in July 2017 and received an advanced grant from the European Research Council in October 2018. The near-term goal of the collaboration is to build a precursor version of the experiment, called BabyIAXO, which will be located at DESY , Germany. The IAXO Collaboration is formed by 21 institutes from 7 different countries. The IAXO experiment

204-451: A {\displaystyle \left(D_{\mu }\right)_{ij}=\partial _{\mu }\delta _{ij}-ig\left(T_{a}\right)_{ij}{\mathcal {A}}_{\mu }^{a}\,} couples the quark field with a coupling strength g {\displaystyle g\,} to the gluon fields via the infinitesimal SU(3) generators T a {\displaystyle T_{a}\,} in the fundamental representation. An explicit representation of these generators

306-405: A meson contains a term that increases in proportion to the distance between the quark and anti-quark ( ∝ r {\displaystyle \propto r} ), which represents some kind of "stiffness" of the interaction between the particle and its anti-particle at large distances, similar to the entropic elasticity of a rubber band (see below). This leads to confinement   of

408-411: A , b and c running from 1 {\displaystyle 1} to 8 {\displaystyle 8} ; and f abc are the structure constants of SU(3) (the generators of the adjoint representation). Note that the rules to move-up or pull-down the a , b , or c indices are trivial , (+, ..., +), so that f = f abc = f bc whereas for the μ or ν indices one has

510-439: A closed loop W ; i.e. ⟨ P W ⟩ {\displaystyle \,\langle P_{W}\rangle } is proportional to the area enclosed by the loop. For this behavior the non-abelian behavior of the gauge group is essential. Further analysis of the content of the theory is complicated. Various techniques have been developed to work with QCD. Some of them are discussed briefly below. This approach

612-408: A corresponding antiquark, of which the charge is exactly opposite. They transform in the conjugate representation to quarks, denoted 3 ¯ {\displaystyle {\bar {\mathbf {3} }}} . According to the rules of quantum field theory , and the associated Feynman diagrams , the above theory gives rise to three basic interactions: a quark may emit (or absorb)

714-490: A document mandated by the CERN Council that forms the cornerstone of Europe's decision-making for the future of particle physics, was last updated in 2020 and affirmed the organisation's role within the open science landscape by stating: "The particle physics community should work with the relevant authorities to help shape the emerging consensus on open science to be adopted for publicly-funded research, and should then implement

816-666: A facility for the development of grid computing , hosting projects including the Enabling Grids for E-sciencE (EGEE) and LHC Computing Grid . It also hosts the CERN Internet Exchange Point (CIXP), one of the two main internet exchange points in Switzerland. As of 2022 , CERN employs ten times more engineers and technicians than research physicists. CERN operates a network of seven accelerators and two decelerators, and some additional small accelerators. Each machine in

918-413: A field theory model in which quarks interact with gluons. Perhaps the first remark that quarks should possess an additional quantum number was made as a short footnote in the preprint of Boris Struminsky in connection with the Ω hyperon being composed of three strange quarks with parallel spins (this situation was peculiar, because since quarks are fermions , such a combination is forbidden by

1020-415: A field theory. The difference between Feynman's and Gell-Mann's approaches reflected a deep split in the theoretical physics community. Feynman thought the quarks have a distribution of position or momentum, like any other particle, and he (correctly) believed that the diffusion of parton momentum explained diffractive scattering . Although Gell-Mann believed that certain quark charges could be localized, he

1122-476: A force can themselves radiate further carrier particles. (This is different from QED, where the photons that carry the electromagnetic force do not radiate further photons.) The discovery of asymptotic freedom in the strong interactions by David Gross , David Politzer and Frank Wilczek allowed physicists to make precise predictions of the results of many high energy experiments using the quantum field theory technique of perturbation theory . Evidence of gluons

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1224-456: A former director of CERN, when the name was changed, the abbreviation could have become the awkward OERN, and Werner Heisenberg said that this could "still be CERN even if the name is [not]". CERN's first president was Sir Benjamin Lockspeiser . Edoardo Amaldi was the general secretary of CERN at its early stages when operations were still provisional, and the first Director-General (1954)

1326-428: A gluon, a gluon may emit (or absorb) a gluon, and two gluons may directly interact. This contrasts with QED , in which only the first kind of interaction occurs, since photons have no charge. Diagrams involving Faddeev–Popov ghosts must be considered too (except in the unitarity gauge ). Detailed computations with the above-mentioned Lagrangian show that the effective potential between a quark and its anti-quark in

1428-643: A high detection efficiency in the ROI (1 – 10 keV ) where the Primakoff axion signal is expected. They also need a very low radioactive background in ROI of under 10 − 7 c o u n t s k e V − 1 c m − 2 s − 1 {\displaystyle \mathrm {10^{-7}counts\,keV^{-1}cm^{-2}s^{-1}} } (less than 3 counts per year of data). To reach this background level,

1530-425: A meson. However, the numerical sign problem makes it difficult to use lattice methods to study QCD at high density and low temperature (e.g. nuclear matter or the interior of neutron stars). A well-known approximation scheme, the 1 ⁄ N expansion , starts from the idea that the number of colors is infinite, and makes a series of corrections to account for the fact that it is not. Until now, it has been

1632-489: A next-generation enhanced helioscope, with a signal to noise ratio five orders of magnitude higher compared to current-day detectors. The cross-sectional area of the magnet equipped with an X-ray focusing optics is meant to increase this signal to background ratio. When the solar axions interact with the magnetic field, some of them may convert into photons through the Primakoff effect . These photons would then be detected by

1734-574: A policy of open science for the field". Beyond the policy level, CERN has established a variety of services and tools to enable and guide open science at CERN, and in particle physics more generally. On the publishing side, CERN has initiated and operates a global cooperative project, the Sponsoring Consortium for Open Access Publishing in Particle Physics , SCOAP3, to convert scientific articles in high-energy physics to open access. In 2018,

1836-567: A technological prototype of all the subsystems of the helioscope as an first step to explore further improvements to the final IAXO experiment. It will consist of a 10 m long magnet with 2 bores and 2 detection lines equipped with an X-ray optic and an ultra-low background X-ray detector each. BabyIAXO will be set up in the HERA South Hall at DESY in Hamburg (Germany) by the IAXO collaboration with

1938-758: Is chiral perturbation theory or ChiPT, which is the QCD effective theory at low energies. More precisely, it is a low energy expansion based on the spontaneous chiral symmetry breaking of QCD, which is an exact symmetry when quark masses are equal to zero, but for the u, d and s quark, which have small mass, it is still a good approximate symmetry. Depending on the number of quarks that are treated as light, one uses either SU(2) ChiPT or SU(3) ChiPT. Other effective theories are heavy quark effective theory (which expands around heavy quark mass near infinity), and soft-collinear effective theory (which expands around large ratios of energy scales). In addition to effective theories, models like

2040-547: Is spontaneously broken by the QCD vacuum to the vector (L+R) SU V ( N f ) with the formation of a chiral condensate . The vector symmetry, U B (1) corresponds to the baryon number of quarks and is an exact symmetry. The axial symmetry U A (1) is exact in the classical theory, but broken in the quantum theory, an occurrence called an anomaly . Gluon field configurations called instantons are closely related to this anomaly. There are two different types of SU(3) symmetry: there

2142-405: Is based on asymptotic freedom, which allows perturbation theory to be used accurately in experiments performed at very high energies. Although limited in scope, this approach has resulted in the most precise tests of QCD to date. Among non-perturbative approaches to QCD, the most well established is lattice QCD . This approach uses a discrete set of spacetime points (called the lattice) to reduce

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2244-401: Is based on the helioscope principle. Axions can be produced in stars (like the sun) via the Primakoff effect and other mechanisms. These axions would reach the helioscope and would be converted into soft X-ray photons in the presence of a magnetic field. Then, these photons travel through a focusing X-ray optics, and are expected as an excess of signal in the detector when the magnet points to

2346-492: Is deduced from observations. These can be QCD is a non-abelian gauge theory (or Yang–Mills theory ) of the SU(3) gauge group obtained by taking the color charge to define a local symmetry. Since the strong interaction does not discriminate between different flavors of quark, QCD has approximate flavor symmetry , which is broken by the differing masses of the quarks. There are additional global symmetries whose definitions require

2448-505: Is given by T a = λ a / 2 {\displaystyle T_{a}=\lambda _{a}/2\,} , wherein the λ a ( a = 1 … 8 ) {\displaystyle \lambda _{a}\,(a=1\ldots 8)\,} are the Gell-Mann matrices . The symbol G μ ν a {\displaystyle G_{\mu \nu }^{a}\,} represents

2550-407: Is practically no interaction between the particles. This is in contrast – more precisely one would say dual – to what one is used to, since usually one connects the absence of interactions with large  distances. However, as already mentioned in the original paper of Franz Wegner, a solid state theorist who introduced 1971 simple gauge invariant lattice models, the high-temperature behaviour of

2652-484: Is the gauge covariant derivative ; the γ are Gamma matrices connecting the spinor representation to the vector representation of the Lorentz group . Herein, the gauge covariant derivative ( D μ ) i j = ∂ μ δ i j − i g ( T a ) i j A μ

2754-402: Is the quark field, a dynamical function of spacetime, in the fundamental representation of the SU(3) gauge group , indexed by i {\displaystyle i} and j {\displaystyle j} running from 1 {\displaystyle 1} to 3 {\displaystyle 3} ; D μ {\displaystyle D_{\mu }}

2856-420: Is the symmetry that acts on the different colors of quarks, and this is an exact gauge symmetry mediated by the gluons, and there is also a flavor symmetry that rotates different flavors of quarks to each other, or flavor SU(3) . Flavor SU(3) is an approximate symmetry of the vacuum of QCD, and is not a fundamental symmetry at all. It is an accidental consequence of the small mass of the three lightest quarks. In

2958-604: Is to provide the particle accelerators and other infrastructure needed for high-energy physics research – consequently, numerous experiments have been constructed at CERN through international collaborations. CERN is the site of the Large Hadron Collider (LHC), the world's largest and highest-energy particle collider. The main site at Meyrin hosts a large computing facility, which is primarily used to store and analyze data from experiments, as well as simulate events . As researchers require remote access to these facilities,

3060-544: The France–Switzerland border . It comprises 24 member states . Israel, admitted in 2013, is the only non-European full member. CERN is an official United Nations General Assembly observer . The acronym CERN is also used to refer to the laboratory; in 2019, it had 2,660 scientific, technical, and administrative staff members, and hosted about 12,400 users from institutions in more than 70 countries. In 2016, CERN generated 49 petabytes of data. CERN's main function

3162-682: The Greek word χρῶμα ( chrōma , "color") is applied to the theory of color charge, "chromodynamics". With the invention of bubble chambers and spark chambers in the 1950s, experimental particle physics discovered a large and ever-growing number of particles called hadrons . It seemed that such a large number of particles could not all be fundamental . First, the particles were classified by charge and isospin by Eugene Wigner and Werner Heisenberg ; then, in 1953–56, according to strangeness by Murray Gell-Mann and Kazuhiko Nishijima (see Gell-Mann–Nishijima formula ). To gain greater insight,

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3264-477: The Nambu–Jona-Lasinio model and the chiral model are often used when discussing general features. Based on an Operator product expansion one can derive sets of relations that connect different observables with each other. The notion of quark flavors was prompted by the necessity of explaining the properties of hadrons during the development of the quark model . The notion of color was necessitated by

3366-454: The Pauli exclusion principle ): Three identical quarks cannot form an antisymmetric S-state. In order to realize an antisymmetric orbital S-state, it is necessary for the quark to have an additional quantum number. Boris Struminsky was a PhD student of Nikolay Bogolyubov . The problem considered in this preprint was suggested by Nikolay Bogolyubov, who advised Boris Struminsky in this research. In

3468-529: The QCD vacuum there are vacuum condensates of all the quarks whose mass is less than the QCD scale. This includes the up and down quarks, and to a lesser extent the strange quark, but not any of the others. The vacuum is symmetric under SU(2) isospin rotations of up and down, and to a lesser extent under rotations of up, down, and strange, or full flavor group SU(3), and the observed particles make isospin and SU(3) multiplets. The approximate flavor symmetries do have associated gauge bosons, observed particles like

3570-435: The baryon number , which is 1 ⁄ 3 for each quark, hypercharge and one of the flavor quantum numbers . Gluons are spin-1 bosons that also carry color charges , since they lie in the adjoint representation 8 of SU(3). They have no electric charge, do not participate in the weak interactions, and have no flavor. They lie in the singlet representation 1 of all these symmetry groups. Each type of quark has

3672-447: The original model , e.g. the strong decay of correlations at large distances, corresponds to the low-temperature behaviour of the (usually ordered!) dual model , namely the asymptotic decay of non-trivial correlations, e.g. short-range deviations from almost perfect arrangements, for short distances. Here, in contrast to Wegner, we have only the dual model, which is that one described in this article. The color group SU(3) corresponds to

3774-538: The proton , neutron and pion . QCD is a type of quantum field theory called a non-abelian gauge theory , with symmetry group SU(3) . The QCD analog of electric charge is a property called color . Gluons are the force carriers of the theory, just as photons are for the electromagnetic force in quantum electrodynamics . The theory is an important part of the Standard Model of particle physics . A large body of experimental evidence for QCD has been gathered over

3876-476: The quark–gluon plasma is a non-perturbative test bed for QCD that still remains to be properly exploited. One qualitative prediction of QCD is that there exist composite particles made solely of gluons called glueballs that have not yet been definitively observed experimentally. A definitive observation of a glueball with the properties predicted by QCD would strongly confirm the theory. In principle, if glueballs could be definitively ruled out, this would be

3978-1085: The CERN model: .cern is a top-level domain for CERN. It was registered on 13 August 2014. On 20 October 2015, CERN moved its main Website to https://home.cern . The Open Science movement focuses on making scientific research openly accessible and on creating knowledge through open tools and processes. Open access , open data , open source software and hardware , open licenses , digital preservation and reproducible research are primary components of open science and areas in which CERN has been working towards since its formation. CERN has developed policies and official documents that enable and promote open science, starting with CERN's founding convention in 1953 which indicated that all its results are to be published or made generally available. Since then, CERN published its open access policy in 2014, which ensures that all publications by CERN authors will be published with gold open access and most recently an open data policy that

4080-502: The LHC accelerator and: Many activities at CERN currently involve operating the Large Hadron Collider (LHC) and the experiments for it. The LHC represents a large-scale, worldwide scientific cooperation project. The LHC tunnel is located 100 metres underground, in the region between Geneva International Airport and the nearby Jura mountains . The majority of its length is on the French side of

4182-411: The LHC. The first beam was circulated through the entire LHC on 10 September 2008, but the system failed 10 days later because of a faulty magnet connection, and it was stopped for repairs on 19 September 2008. The LHC resumed operation on 20 November 2009 by successfully circulating two beams, each with an energy of 3.5  teraelectronvolts (TeV). The challenge for the engineers was then to line up

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4284-543: The LINAC 2 linear accelerator injector was decommissioned and replaced by a new injector accelerator, the LINAC4 . CERN, in collaboration with groups worldwide, is investigating two main concepts for future accelerators: A linear electron-positron collider with a new acceleration concept to increase the energy ( CLIC ) and a larger version of the LHC, a project currently named Future Circular Collider . The smaller accelerators are on

4386-614: The SCOAP3 partnership represented 3,000+ libraries from 44 countries and 3 intergovernmental organizations who have worked collectively to convert research articles in high-energy physics across 11 leading journals in the discipline to open access. Public-facing results can be served by various CERN-based services depending on their use case: the CERN Open Data portal , Zenodo , the CERN Document Server , INSPIRE and HEPData are

4488-630: The SPS accelerator. Most of the roads on the CERN Meyrin and Prévessin sites are named after famous physicists, such as Wolfgang Pauli , who pushed for CERN's creation. Other notable names are Richard Feynman , Albert Einstein , and Bohr . Since its foundation by 12 members in 1954, CERN regularly accepted new members. All new members have remained in the organization continuously since their accession, except Spain and Yugoslavia. Spain first joined CERN in 1961, withdrew in 1969, and rejoined in 1983. Yugoslavia

4590-671: The Sun. The potential of the experiment can be estimated by means of the figure of merit (FOM) , which can be defined as F O M ∼ B 2 L 2 A × ϵ d b − 1 / 2 × ϵ o α − 1 / 2 × ϵ t 1 / 2 t 1 / 2 {\displaystyle FOM\sim B^{2}L^{2}A\times \epsilon _{d}b^{-1/2}\times \epsilon _{o}\alpha ^{-1/2}\times \epsilon _{t}^{1/2}t^{1/2}} , where

4692-565: The United Kingdom, and Yugoslavia . Several important achievements in particle physics have been made through experiments at CERN. They include: In September 2011, CERN attracted media attention when the OPERA Collaboration reported the detection of possibly faster-than-light neutrinos . Further tests showed that the results were flawed due to an incorrectly connected GPS synchronization cable. The 1984 Nobel Prize for Physics

4794-578: The World Wide Web. A copy of the first webpage, created by Berners-Lee, is still published on the World Wide Web Consortium 's website as a historical document. The first website was activated in 1991. On 30 April 1993, CERN announced that the World Wide Web would be free to anyone. It became the dominant way through which most users interact with the Internet . More recently, CERN has become

4896-480: The X-ray detectors of the helioscope. The magnet will be a purpose‐built large‐scale superconductor with a length of 20 m and an average field strength of 2.5  Tesla . The whole helioscope will feature 8 bores of 60 cm diameter. Each of the bores will be equipped with a focusing X-ray optic and a low-background X-ray detector. The helioscope will also be equipped with a mechanical system allowing it to follow

4998-497: The analytically intractable path integrals of the continuum theory to a very difficult numerical computation that is then carried out on supercomputers like the QCDOC , which was constructed for precisely this purpose. While it is a slow and resource-intensive approach, it has wide applicability, giving insight into parts of the theory inaccessible by other means, in particular into the explicit forces acting between quarks and antiquarks in

5100-643: The ancillary cryogenic and access sites are in Switzerland. The largest of the experimental sites is the Prévessin site, also known as the North Area, which is the target station for non-collider experiments on the SPS accelerator. Other sites are the ones which were used for the UA1 , UA2 and the LEP experiments. The latter are used by LHC experiments. Outside of the LEP and LHC experiments, most are officially named and numbered after

5202-402: The area of the focused signal on the detector readout ( α {\displaystyle \alpha } ). The last term is related to the time ( t ) of operation and the fraction of time that sun is tracked ( ϵ t {\displaystyle \epsilon _{t}} ). The objective is to maximise the value of the figure of merit in order to optimise the sensitivity of

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5304-496: The beginning of 1965, Nikolay Bogolyubov , Boris Struminsky and Albert Tavkhelidze wrote a preprint with a more detailed discussion of the additional quark quantum degree of freedom. This work was also presented by Albert Tavkhelidze without obtaining consent of his collaborators for doing so at an international conference in Trieste (Italy), in May 1965. A similar mysterious situation

5406-512: The behavior of Wilson loops can distinguish confined and deconfined phases. Quarks are massive spin- 1 ⁄ 2 fermions that carry a color charge whose gauging is the content of QCD. Quarks are represented by Dirac fields in the fundamental representation 3 of the gauge group SU(3) . They also carry electric charge (either − 1 ⁄ 3 or + 2 ⁄ 3 ) and participate in weak interactions as part of weak isospin doublets. They carry global quantum numbers including

5508-547: The border. It uses the 27 km circumference circular tunnel previously occupied by the Large Electron–Positron Collider (LEP), which was shut down in November 2000. CERN's existing PS/SPS accelerator complexes are used to pre-accelerate protons and lead ions which are then injected into the LHC. Eight experiments ( CMS , ATLAS , LHCb , MoEDAL , TOTEM , LHCf , FASER and ALICE ) are located along

5610-446: The chain increases the energy of particle beams before delivering them to experiments or to the next more powerful accelerator. The decelerators naturally decrease the energy of particle beams before delivering them to experiments or further accelerators/decelerators. Before an experiment is able to use the network of accelerators, it must be approved by the various Scientific Committees of CERN . Currently (as of 2022) active machines are

5712-463: The collider; each of them studies particle collisions from a different aspect, and with different technologies. Construction for these experiments required an extraordinary engineering effort. For example, a special crane was rented from Belgium to lower pieces of the CMS detector into its cavern, since each piece weighed nearly 2,000 tons. The first of the approximately 5,000 magnets necessary for construction

5814-454: The concept of hypertext , the idea was designed to facilitate information sharing between researchers. This stemmed from Berners-Lee's earlier work at CERN on a database named ENQUIRE . A colleague, Robert Cailliau , became involved in 1990. In 1995, Berners-Lee and Cailliau were jointly honoured by the Association for Computing Machinery for their contributions to the development of

5916-467: The core services used by the researchers and community at CERN, as well as the wider high-energy physics community for the publication of their documents, data, software, multimedia, etc. CERN's efforts towards preservation and reproducible research are best represented by a suite of services addressing the entire physics analysis lifecycle, such as data, software and computing environment. CERN Analysis Preservation helps researchers to preserve and document

6018-547: The design collision rate was exceeded for the first time. A second two-year period of shutdown begun at the end of 2018. As of October 2019, the construction is on-going to upgrade the LHC's luminosity in a project called High Luminosity LHC (HL–LHC). This project should see the LHC accelerator upgraded by 2026 to an order of magnitude higher luminosity. As part of the HL–LHC upgrade project, also other CERN accelerators and their subsystems are receiving upgrades. Among other work,

6120-480: The detector relies on: CERN The European Organization for Nuclear Research , known as CERN ( / s ɜːr n / ; French pronunciation: [sɛʁn] ; Organisation européenne pour la recherche nucléaire ), is an intergovernmental organization that operates the largest particle physics laboratory in the world. Established in 1954, it is based in Meyrin , western suburb of Geneva , on

6222-470: The experiment to axions. IAXO will primarily be searching for solar axions, along with the potential to observe the quantum chromodynamics (QCD) axion in the mass range of 1 meV to 1 eV. It is also expected to be capable of discovering ALPs. Therefore, IAXO will have the potential to solve both the strong CP problem and the dark matter problem . It could also be later adapted to test models of hypothesized hidden photons or chameleons . Also,

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6324-460: The first factor is related to the magnet and depends on the magnetic field ( B ), the length of the magnet ( L ) and the area of the bore ( A ). The second part depends on the efficiency ( ϵ d {\displaystyle \epsilon _{d}} ) and background ( b ) of the detector. The third is related to the optics, more specifically the efficiency ( ϵ o {\displaystyle \epsilon _{o}} ) and

6426-710: The flight models of the XMM-Newton space mission that belongs to the ESA . IAXO and BabyIAXO will have multiple and diverse detectors working in parallel, mounted to the different magnet bores. Based upon the experience from CAST , the baseline detector technology will be a Time Projection Chamber (TPC) with a Micromegas readout. In addition, there are several other technologies under study: GridPix, Metallic Magnetic Calorimeters (MMC), Transition Edge Sensors (TES) and Silicon Drift Detectors (SDD). The detectors for this experiment need to meet certain technical requirements. They need

6528-410: The following other countries: International research institutions, such as CERN, can aid in science diplomacy. A large number of institutes around the world are associated to CERN through current collaboration agreements and/or historical links. The list below contains organizations represented as observers to the CERN Council, organizations to which CERN is an observer and organizations based on

6630-473: The gauge invariant gluon field strength tensor , analogous to the electromagnetic field strength tensor , F , in quantum electrodynamics . It is given by: where A μ a ( x ) {\displaystyle {\mathcal {A}}_{\mu }^{a}(x)\,} are the gluon fields , dynamical functions of spacetime, in the adjoint representation of the SU(3) gauge group, indexed by

6732-439: The hadrons were sorted into groups having similar properties and masses using the eightfold way , invented in 1961 by Gell-Mann and Yuval Ne'eman . Gell-Mann and George Zweig , correcting an earlier approach of Shoichi Sakata , went on to propose in 1963 that the structure of the groups could be explained by the existence of three flavors of smaller particles inside the hadrons: the quarks . Gell-Mann also briefly discussed

6834-411: The involvement of DESY and CERN. The data taking by BabyIAXO is scheduled to start in 2028. The superconducting magnet has a toroidal multibore configuration in order to generate a strong magnetic field over a large volume. It will be a 10 m long magnet consisting of two different coils made out of 35 km Rutherford cable . This configuration will generate a 2.5 Tesla magnetic field within

6936-535: The lab has historically been a major wide area network hub. CERN is also the birthplace of the World Wide Web . The convention establishing CERN was ratified on 29 September 1954 by 12 countries in Western Europe. The acronym CERN originally represented the French words for Conseil Européen pour la Recherche Nucléaire ('European Council for Nuclear Research'), which was a provisional council for building

7038-562: The laboratory, established by 12 European governments in 1952. During these early years, the council worked at the University of Copenhagen under the direction of Niels Bohr before moving to its present site near Geneva. The acronym was retained for the new laboratory after the provisional council was dissolved, even though the name changed to the current Organisation européenne pour la recherche nucléaire ('European Organization for Nuclear Research') in 1954. According to Lew Kowarski ,

7140-418: The local symmetry whose gauging gives rise to QCD. The electric charge labels a representation of the local symmetry group U(1), which is gauged to give QED : this is an abelian group . If one considers a version of QCD with N f flavors of massless quarks, then there is a global ( chiral ) flavor symmetry group SU L ( N f ) × SU R ( N f ) × U B (1) × U A (1). The chiral symmetry

7242-406: The magnet can be used as a haloscope to search for axion dark matter. IAXO will have a sensitivity to the axion-photon coupling 1–1.5 order of magnitude higher than that achieved by previous detectors. Any particle found by IAXO will be at the least a sub-dominant component of the dark matter . The observatory would be capable of observing from a wide range of sources given below. IAXO will be

7344-492: The main Meyrin site, also known as the West Area, which was originally built in Switzerland alongside the French border, but has been extended to span the border since 1965. The French side is under Swiss jurisdiction and there is no obvious border within the site, apart from a line of marker stones. The SPS and LEP/LHC tunnels are almost entirely outside the main site, and are mostly buried under French farmland and invisible from

7446-675: The new particles, and because an elementary particle back then was defined as a particle that could be separated and isolated, Gell-Mann often said that quarks were merely convenient mathematical constructs, not real particles. The meaning of this statement was usually clear in context: He meant quarks are confined, but he also was implying that the strong interactions could probably not be fully described by quantum field theory. Richard Feynman argued that high energy experiments showed quarks are real particles: he called them partons (since they were parts of hadrons). By particles, Feynman meant objects that travel along paths, elementary particles in

7548-472: The non-trivial relativistic rules corresponding to the metric signature (+ − − −). The variables m and g correspond to the quark mass and coupling of the theory, respectively, which are subject to renormalization. An important theoretical concept is the Wilson loop (named after Kenneth G. Wilson ). In lattice QCD, the final term of the above Lagrangian is discretized via Wilson loops, and more generally

7650-433: The notion of chirality , discrimination between left and right-handed. If the spin of a particle has a positive projection on its direction of motion then it is called right-handed; otherwise, it is left-handed. Chirality and handedness are not the same, but become approximately equivalent at high energies. As mentioned, asymptotic freedom means that at large energy – this corresponds also to short distances – there

7752-479: The predictions are harder to make. The best is probably the running of the QCD coupling as probed through lattice computations of heavy-quarkonium spectra. There is a recent claim about the mass of the heavy meson B c . Other non-perturbative tests are currently at the level of 5% at best. Continuing work on masses and form factors of hadrons and their weak matrix elements are promising candidates for future quantitative tests. The whole subject of quark matter and

7854-441: The puzzle of the Δ . This has been dealt with in the section on the history of QCD . The first evidence for quarks as real constituent elements of hadrons was obtained in deep inelastic scattering experiments at SLAC . The first evidence for gluons came in three-jet events at PETRA . Several good quantitative tests of perturbative QCD exist: Quantitative tests of non-perturbative QCD are fewer, because

7956-484: The quarks to the interior of hadrons, i.e. mesons and nucleons , with typical radii R c , corresponding to former " Bag models " of the hadrons The order of magnitude of the "bag radius" is 1 fm (= 10  m). Moreover, the above-mentioned stiffness is quantitatively related to the so-called "area law" behavior of the expectation value of the Wilson loop product P W of the ordered coupling constants around

8058-567: The research being performed there. At the sixth session of the CERN Council in Paris from 29 June to 1 July 1953, the convention establishing the organization was signed, subject to ratification, by 12 states. The convention was gradually ratified by the 12 founding Member States: Belgium, Denmark, France, the Federal Republic of Germany , Greece, Italy, the Netherlands, Norway, Sweden, Switzerland,

8160-409: The rho and the omega, but these particles are nothing like the gluons and they are not massless. They are emergent gauge bosons in an approximate string description of QCD . The dynamics of the quarks and gluons are defined by the quantum chromodynamics Lagrangian . The gauge invariant QCD Lagrangian is where ψ i ( x ) {\displaystyle \psi _{i}(x)\,}

8262-497: The search for the Higgs boson . When the 7 TeV experimental period ended, the LHC increased to 8 TeV (4 TeV per proton) starting March 2012, and soon began particle collisions at that energy. In July 2012, CERN scientists announced the discovery of a new sub-atomic particle that was later confirmed to be the Higgs boson . In March 2013, CERN announced that the measurements performed on the newly found particle allowed it to conclude that it

8364-644: The site where they were located. For example, NA32 was an experiment looking at the production of so-called " charmed " particles and located at the Prévessin (North Area) site. WA22 used the Big European Bubble Chamber (BEBC) at the Meyrin (West Area) site to examine neutrino interactions. The UA1 and UA2 experiments were considered to be in the Underground Area, i.e. situated underground at sites on

8466-510: The source of qualitative insight rather than a method for quantitative predictions. Modern variants include the AdS/CFT approach. For specific problems, effective theories may be written down that give qualitatively correct results in certain limits. In the best of cases, these may then be obtained as systematic expansions in some parameters of the QCD Lagrangian. One such effective field theory

8568-402: The strong interactions. In 1973 the concept of color as the source of a "strong field" was developed into the theory of QCD by physicists Harald Fritzsch and Heinrich Leutwyler , together with physicist Murray Gell-Mann. In particular, they employed the general field theory developed in 1954 by Chen Ning Yang and Robert Mills (see Yang–Mills theory ), in which the carrier particles of

8670-445: The sun consistently throughout half of the day. Tracking data will be taken during the day and background data will be taken during the night, which is the ideal split of data and background for properly estimating the event rate in each case and determining the axion signal. BabyIAXO is an intermediate scale version of the IAXO experiment with axion discovery potential and a FOM around 100 times larger than CAST . It will also serve as

8772-449: The surface. They have surface sites at points around them, either as the location of buildings associated with experiments or other facilities needed to operate the colliders such as cryogenic plants and access shafts. The experiments are located at the same underground level as the tunnels at these sites. Three of these experimental sites are in France, with ATLAS in Switzerland, and some of

8874-607: The theoretical description of the Higgs mechanism in the year after the Higgs boson was found by CERN experiments. CERN pioneered the introduction of TCP/IP for its intranet , beginning in 1984. This played an influential role in the adoption of the TCP/IP in Europe (see History of the Internet and Protocol Wars ). In 1989, the World Wide Web was invented at CERN by Tim Berners-Lee . Based on

8976-581: The theory is verified within lattice QCD computations, but is not mathematically proven. One of the Millennium Prize Problems announced by the Clay Mathematics Institute requires a claimant to produce such a proof. Other aspects of non-perturbative QCD are the exploration of phases of quark matter , including the quark–gluon plasma . Every field theory of particle physics is based on certain symmetries of nature whose existence

9078-419: The three kinds of color (red, green and blue) perceived by humans . Other than this nomenclature, the quantum parameter "color" is completely unrelated to the everyday, familiar phenomenon of color. The force between quarks is known as the colour force (or color force ) or strong interaction , and is responsible for the nuclear force . Since the theory of electric charge is dubbed " electrodynamics ",

9180-606: The two 70 cm diameter bores. The magnet subsystem is inspired by the ATLAS experiment . Since BabyIAXO will have two bores in the magnet, two X-ray optics are required to operate in parallel. Both of them are Wolter optics (type I). One of the two BabyIAXO optics will be based on a mature technology developed for NASA 's NuStar X-ray satellite . The signal from the 0.7 m diameter bore will be focused to 0.2 c m 2 {\displaystyle \mathrm {cm^{2}} } area. The second BabyIAXO optics will be one of

9282-462: The two beams so that they smashed into each other. This is like "firing two needles across the Atlantic and getting them to hit each other" according to Steve Myers, director for accelerators and technology. On 30 March 2010, the LHC successfully collided two proton beams with 3.5 TeV of energy per proton, resulting in a 7 TeV collision energy. This was enough to start the main research program, including

9384-401: The various components of their physics analyses. REANA (Reusable Analyses) enables the instantiating of preserved research data analyses on the cloud. Quantum chromodynamics In theoretical physics , quantum chromodynamics ( QCD ) is the study of the strong interaction between quarks mediated by gluons . Quarks are fundamental particles that make up composite hadrons such as

9486-782: The years. QCD exhibits three salient properties: Physicist Murray Gell-Mann coined the word quark in its present sense. It originally comes from the phrase "Three quarks for Muster Mark" in Finnegans Wake by James Joyce . On June 27, 1978, Gell-Mann wrote a private letter to the editor of the Oxford English Dictionary , in which he related that he had been influenced by Joyce's words: "The allusion to three quarks seemed perfect." (Originally, only three quarks had been discovered.) The three kinds of charge in QCD (as opposed to one in quantum electrodynamics or QED) are usually referred to as " color charge " by loose analogy to

9588-471: Was Felix Bloch . The laboratory was originally devoted to the study of atomic nuclei , but was soon applied to higher-energy physics , concerned mainly with the study of interactions between subatomic particles . Therefore, the laboratory operated by CERN is commonly referred to as the European laboratory for particle physics ( Laboratoire européen pour la physique des particules ), which better describes

9690-401: Was a Higgs boson. In early 2013, the LHC was deactivated for a two-year maintenance period, to strengthen the electrical connections between magnets inside the accelerator and for other upgrades. On 5 April 2015, after two years of maintenance and consolidation, the LHC restarted for a second run. The first ramp to the record-breaking energy of 6.5 TeV was performed on 10 April 2015. In 2016,

9792-599: Was a founding member of CERN but quit in 1961. Of the 24 members, Israel joined CERN as a full member in January 2014, becoming the first, and currently only, non-European full member. The budget contributions of member states are computed based on their GDP. Associate Members, Candidates: Three countries have observer status: Also observers are the following international organizations: Non-Member States (with dates of Co-operation Agreements) currently involved in CERN programmes are: CERN also has scientific contacts with

9894-420: Was awarded to Carlo Rubbia and Simon van der Meer for the developments that resulted in the discoveries of the W and Z bosons. The 1992 Nobel Prize for Physics was awarded to CERN staff researcher Georges Charpak "for his invention and development of particle detectors, in particular the multiwire proportional chamber ". The 2013 Nobel Prize for Physics was awarded to François Englert and Peter Higgs for

9996-428: Was discovered in three-jet events at PETRA in 1979. These experiments became more and more precise, culminating in the verification of perturbative QCD at the level of a few percent at LEP , at CERN . The other side of asymptotic freedom is confinement . Since the force between color charges does not decrease with distance, it is believed that quarks and gluons can never be liberated from hadrons. This aspect of

10098-505: Was endorsed by the four main LHC collaborations ( ALICE , ATLAS , CMS and LHCb ). The open data policy complements the open access policy, addressing the public release of scientific data collected by LHC experiments after a suitable embargo period. Prior to this open data policy, guidelines for data preservation, access and reuse were implemented by each collaboration individually through their own policies which are updated when necessary. The European Strategy for Particle Physics,

10200-538: Was lowered down a special shaft at in March 2005. The LHC has begun to generate vast quantities of data, which CERN streams to laboratories around the world for distributed processing, making use of a specialized grid infrastructure, the LHC Computing Grid . In April 2005, a trial successfully streamed 600 MB/s to seven different sites across the world. In August 2008, the initial particle beams were injected into

10302-470: Was open to the possibility that the quarks themselves could not be localized because space and time break down. This was the more radical approach of S-matrix theory . James Bjorken proposed that pointlike partons would imply certain relations in deep inelastic scattering of electrons and protons, which were verified in experiments at SLAC in 1969. This led physicists to abandon the S-matrix approach for

10404-468: Was with the Δ baryon ; in the quark model, it is composed of three up quarks with parallel spins. In 1964–65, Greenberg and Han – Nambu independently resolved the problem by proposing that quarks possess an additional SU(3) gauge degree of freedom , later called color charge. Han and Nambu noted that quarks might interact via an octet of vector gauge bosons : the gluons . Since free quark searches consistently failed to turn up any evidence for

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