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{{redirect|LHC}} |
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{{LHC}} |
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{{Hadron colliders}} |
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[[Image:Large Hadron Collider at CERN map.svg|thumb|Map of the Large Hadron Collider at CERN]] |
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The '''Large Hadron Collider''' ('''LHC''') is the world's largest and highest-energy [[particle accelerator]] complex, intended to [[Collider|collide]] opposing [[Charged particle beam|beams]] of [[proton]]s or [[lead]], two of several types of [[hadron]]s, at up to 99.99 percent the [[speed of light]].<ref>[http://public.web.cern.ch/public/en/LHC/Facts-en.html LHC: Facts and Figures, "European Organization for Nuclear Research" </ref> |
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The LHC was built by the [[CERN|European Organization for Nuclear Research]] (CERN), and lies underneath the Franco-Swiss border between the [[Jura Mountains]] and the [[Alps]] near [[Geneva]], [[Switzerland]]. It is funded by and built in collaboration with over 10,000 [[scientist]]s and [[engineer]]s from over 100 countries as well as hundreds of [[University|universities]] and [[Laboratory|laboratories]]<ref>[http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2008/09/16/sciwriters116.xml Large Hadron Collider: thirteen ways to change the world]</ref> with the intention of testing various predictions of high-energy physics, including the existence of the hypothesized [[Higgs boson]]. |
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On 10 September 2008 the LHC accelerated its first proton streams, only to have operations suspended on 19 September 2008 due to equipment failure.<ref>Highfield, Roger, [http://www.telegraph.co.uk/earth/main.jhtml?view=DETAILS&grid=&xml=/earth/2008/09/20/scilhc120.xml "Large Hadron Collider to be turned off for two months following damage"], ''Telegraph Online'', 20 September 2008 </ref> Owing to the already planned winter shutdown, the collider will not be operational again until the spring of 2009.<ref name="CERNPress2">{{cite web | url=http://press.web.cern.ch/press/PressReleases/Releases2008/PR10.08E.html | title=LHC re-start scheduled for 2009 | accessdate=2008-09-24 | publisher=CERN}}</ref><ref>Higgens, Alexander G., [http://apnews.myway.com/article/20080921/D93B8MNO0.html "Small accidents mean big trouble for supercollider"], ''Associated Press'', 21 September 2008, retrieved 21 September 2008</ref> |
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==Purpose== |
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[[Image:BosonFusion-Higgs.svg|thumb|left|A [[Feynman diagram]] of one way the [[Higgs boson]] may be produced at the LHC. Here, two [[quarks]] each emit a [[W and Z bosons|W or Z boson]], which combine to make a neutral Higgs.]] |
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[[Image:CMS Higgs-event.jpg|thumb|left|A simulated event in the CMS detector, featuring the appearance of the [[Higgs boson]].]] |
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When in operation, about seven thousand scientists from eighty countries will have access to the LHC. |
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It is theorized that the collider will produce the elusive [[Higgs boson]], the last unobserved particle |
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among those predicted by the [[Standard Model]]. The verification of the existence of the Higgs boson would |
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shed light on the mechanism of [[Higgs mechanism|electroweak symmetry breaking]], through which the particles of the Standard Model are thought to acquire their [[mass]]. In addition to the Higgs boson, new particles predicted by possible [[Beyond the Standard Model|extensions of the Standard Model]] might be produced at the LHC. More generally, [[physicist]]s hope that the LHC will enhance their ability to answer the following questions: |
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*Is the [[Higgs mechanism]] for generating [[elementary particle]] [[mass]]es in the [[Standard Model]] indeed realised in nature?<ref>"...in the public presentations of the aspiration of particle physics we hear too often that the goal of the LHC or a [[International Linear Collider|linear collider]] is to check off the last missing particle of the [[Standard Model]], this year’s Holy Grail of particle physics, the Higgs boson. ''The truth is much less boring than that!'' What we’re trying to accomplish is much more exciting, and asking what the world would have been like without the Higgs mechanism is a way of getting at that excitement." -Chris Quigg, [http://arxiv.org/abs/hep-ph/0502070 Nature's Greatest Puzzles]</ref> If so, how many Higgs bosons are there, and what are their masses? |
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* Are [[electromagnetism]], the [[strong nuclear force]] and the [[weak nuclear force]] just different manifestations of a single unified force, as predicted by various [[Grand unification theory|Grand Unification Theories]]? |
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*Why is [[Gravitation|gravity]] so many orders of magnitude weaker than the other three [[fundamental interaction|fundamental forces]]? See also [[Hierarchy problem#The Higgs mass|Hierarchy problem]]. |
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*Is [[Supersymmetry]] realised in nature, implying that the known Standard Model particles have [[superpartner|supersymmetric partners]]? |
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*Will the more precise measurements of the [[mass]]es and [[Particle decay|decays]] of the [[quark]]s continue to be mutually consistent within the Standard Model? |
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*Why are there apparent violations of the [[symmetry in physics|symmetry]] between matter and antimatter? See also [[CP-violation]]. |
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*What is the nature of [[dark matter]] and [[dark energy]]? |
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*Are there [[Kaluza–Klein theory|extra dimensions]]<ref>{{cite web|url=http://randall.physics.harvard.edu/RandallCV/Sciencearticle.pdf|title=Extra Dimensions and Warped Geometries.] ''Science''. Vol. 296, 24 May 2002|last=Randall|first=Lisa}}</ref>, as predicted by various models inspired by [[string theory]], and can we detect them? |
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Of the possible discoveries the LHC might make, only the discovery of the Higgs particle is relatively uncontroversial, but even this is not considered a certainty. [[Stephen Hawking]] said in a BBC interview that "I think it will be much more exciting if we don't find the Higgs. That will show something is wrong, and we need to think again. I have a bet of one hundred dollars that we won't find the Higgs." In the same interview Hawking mentions the possibility of finding superpartners and adds that "whatever the LHC finds, or fails to find, the results will tell us a lot about the structure of the universe."<ref name="news1">[http://news.bbc.co.uk/today/hi/today/newsid_7605000/7605748.stm Stephen Hawking interviewed by the BBC on the switch-on of the Large Hadron Collider]. ''news.bbc.co.uk''. Retrieved on 10 September 2008.</ref> |
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===As an ion collider=== |
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The LHC physics programme is mainly based on [[proton]]–proton collisions. However, shorter running periods, typically one month per year, with heavy-[[ion]] collisions are included in the programme. While lighter ions are considered as well, the baseline scheme deals with [[lead]] ions.<ref>{{cite web|url=http://project-i-lhc.web.cern.ch/project-i-lhc/Welcome.htm|title=Ions for LHC}}</ref> (see [[A Large Ion Collider Experiment]]). This will allow an advancement in the experimental programme currently in progress at the [[Relativistic Heavy Ion Collider]] (RHIC). The aim of the heavy-ion programme is to provide a window on a state of matter known as [[Quark-gluon plasma]], which characterized the early stage of the life of the Universe. |
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==Design== |
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The LHC is the world's largest and highest-energy [[particle accelerator]].<ref name="LHCbooklet">{{cite web |url=http://cdsmedia.cern.ch/img/CERN-Brochure-2008-001-Eng.pdf |title=CERN FAQ — LHC: the guide |accessdate=2008-09-12 |author=CERN Communication Group |year=2008 |month=January |format=PDF |publisher=CERN |location=Geneva |pages=44}}</ref><ref name="TGPngm">{{cite journal | last = Achenbach | first = Joel | authorlink = Joel Achenbach | date = 2008-03-01 | title = The God Particle | journal = [[National Geographic Magazine]] | volume = | issue = | pages = | publisher = [[National Geographic Society]] | issn = 0027-9358 | url = http://ngm.nationalgeographic.com/2008/03/god-particle/achenbach-text | accessdate = 2008-02-25 }}</ref> The collider is contained in a circular tunnel, with a circumference of {{convert|27|km|mi}}, at a depth ranging from 50 to 175 metres underground. |
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The {{nowrap|3.8 [[meter|m]]}} wide concrete-lined tunnel, constructed between 1983 and 1988, was formerly used to house the [[Large Electron-Positron Collider]].<ref>{{cite web|url=http://public.web.cern.ch/PUBLIC/en/Research/LEP-en.html|title=The Z factory|publisher=European Organization for Nuclear Research}}</ref> It crosses the border between [[Switzerland]] and France at four points, with most of it in France. Surface buildings hold ancillary equipment such as compressors, ventilation equipment, control electronics and refrigeration plants. |
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The collider tunnel contains two adjacent parallel beam pipes that intersect at four points, each containing a proton beam, which travel in opposite directions around the ring. Some {{nowrap|1,232 [[dipole magnet]]s}} keep the beams on their circular path, while an additional {{nowrap|392 [[quadrupole magnet]]s}} are used to keep the beams focused, in order to maximize the chances of interaction between the particles in the four intersection points, where the two beams will cross. In total, over {{nowrap|1,600 [[superconducting magnet]]s}} are installed, with most weighing over {{nowrap|27 [[tonne]]s}}. Approximately {{nowrap|96 tonnes}} of [[liquid helium]] is needed to keep the magnets at their operating temperature of {{nowrap|1.9 [[kelvin|K]]}}, making the LHC the largest [[Cryogenics|cryogenic]] facility in the world at liquid helium temperature. |
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[[Image:LHC quadrupole magnets.jpg|thumb|left|Superconducting [[quadrupole magnet|quadrupole electromagnets]] are used to direct the beams to four intersection points, where interactions between protons will take place.]] |
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Once or twice a day, as the protons are accelerated from {{nowrap|450 [[GeV]]}} to {{nowrap|7 [[TeV]],}} the field of the superconducting dipole magnets will be increased from 0.54 to {{nowrap|8.3 [[Tesla (unit)|tesla (T)]]}}. The protons will each have an [[energy]] of {{nowrap|7 TeV}}, giving a total collision energy of {{nowrap|14 TeV}} ({{nowrap|2.2 [[Joule (unit)|μJ]]}}). At this energy the protons have a [[Lorentz factor]] of about 7,500 and move at about 99.999999% of the [[speed of light]]. It will take less than {{nowrap|90 [[microsecond]] (μs)}} for a proton to travel once around the main ring – a speed of about {{nowrap|11,000 revolutions}} per second. Rather than continuous beams, the protons will be bunched together, into {{nowrap|2,808 bunches}}, so that interactions between the two beams will take place at discrete intervals never shorter than {{nowrap|25 [[nanoseconds]] (ns)}} apart. However it will be operated with fewer bunches when it is first commissioned, giving it a bunch crossing interval of {{nowrap|75 ns}}.<ref name ="commissioning">{{cite web|url=http://lhc-commissioning.web.cern.ch/lhc-commissioning/|title=LHC commissioning with beam |publisher=CERN}}</ref> |
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Prior to being injected into the main accelerator, the particles are prepared by a series of systems that successively increase their energy. The first system is the [[linear particle accelerator]] [[LINAC 2]] generating {{nowrap|50 [[MeV]]}} protons, which feeds the [[Proton Synchrotron Booster]] (PSB). There the protons are accelerated to {{nowrap|1.4 GeV}} and injected into the [[Proton Synchrotron]] (PS), where they are accelerated to {{nowrap|26 GeV}}. Finally the [[Super Proton Synchrotron]] (SPS) is used to further increase their energy to {{nowrap|450 GeV}} before they are at last injected (over a period of 20 minutes) into the main ring. Here the proton bunches are accumulated, accelerated (over a period of {{nowrap|20 minutes}}) to their peak {{nowrap|7 TeV}} energy, and finally stored for 10 to {{nowrap|24 hours}} while collisions occur at the four intersection points.<ref name="irfu1">[http://irfu.cea.fr/Phocea/file.php?class=std&file=Seminaires/1595/Dapnia-Nov07-partB.ppt Operational challenges of the LHC]. 53 Microsoft PowerPoint slides.</ref> |
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The LHC will also be used to collide [[lead]] (Pb) [[heavy ion]]s with a collision energy of {{nowrap|1,150 TeV}}. The Pb ions will be first accelerated by the linear accelerator [[LINAC 3]], and the [[Low-Energy Injector Ring]] (LEIR) will be used as an ion storage and cooler unit. The ions then will be further accelerated by the PS and SPS before being injected into LHC ring, where they will reach an energy of {{nowrap|2.76 TeV}} per [[nucleon]]. |
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===Detectors=== |
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[[Image:CMS Yep2 descent.gif|thumb|The Large Hadron Collider's (LHC) [[Compact Muon Solenoid|CMS]] detectors being installed.]] |
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Six detectors have been constructed at the LHC, located underground in large caverns excavated at the LHC's intersection points. Two of them, the [[ATLAS experiment]] and the [[Compact Muon Solenoid]] (CMS), are large, general purpose [[particle detector]]s.<ref name="TGPngm"/> [[A Large Ion Collider Experiment]] (ALICE) and [[LHCb]] have more specific roles and the last two [[TOTEM]] and [[LHCf]] are very much smaller and are for very specialized research. The BBC's summary of the main detectors is:<ref>{{cite web|url=http://news.bbc.co.uk/1/hi/sci/tech/7604293.stm|title=Cern collider ready for power-up|publisher=BBC|author=Paul Rincon|date=9 September 2008|accessdate=2008-09-09}}</ref> |
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*ATLAS – one of two so-called general purpose detectors. Atlas will be used to look for signs of new physics, including the origins of mass and extra dimensions. |
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*CMS – the other general purpose detector will, like ATLAS, hunt for the Higgs boson and look for clues to the nature of dark matter. |
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*ALICE – will study a "liquid" form of matter called [[quark-gluon plasma]] that existed shortly after the [[Big Bang]]. |
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*LHCb – equal amounts of matter and [[anti-matter]] were created in the Big Bang. LHCb will try to investigate what happened to the "missing" anti-matter. |
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==Test timeline== |
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The first beam was circulated through the collider on the morning of 10 September 2008.<ref>{{cite web|url=http://news.bbc.co.uk/2/hi/science/nature/7604293.stm|title=Success for 'Big Bang' experiment|publisher=BBC}}</ref> CERN successfully fired the protons around the tunnel in stages, three kilometres at a time. The particles were fired in a clockwise direction into the accelerator and successfully steered around it at 10:28 local time.<ref>{{cite web|url=http://press.web.cern.ch/press/PressReleases/Releases2008/PR08.08E.html|title=First beam in the LHC - accelerating science |publisher=CERN|accessdate=2008-09-10}}</ref> The LHC successfully completed its first major test: after a series of trial runs, two white dots flashed on a computer screen showing the protons traveled the full length of the collider. It took less than one hour to guide the stream of particles around its inaugural circuit.<ref>{{cite web | url=http://www.timesonline.co.uk/tol/news/uk/science/article4722261.ece | title=Scientists cheer as protons complete first circuit of Large Hadron Collider | publisher=Times Online | accessdate=2008=-0=24}}</ref> CERN next successfully sent a beam of protons in a counterclockwise direction, taking slightly longer at one and a half hours due to a problem with the cryogenics, with the full circuit being completed at 14:59. |
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On 19 September a [[Superconducting magnet#Magnet quench|quench]] occurred in about 100 bending magnets in sectors 3-4, causing loss of approximately one ton of liquid helium, which was vented into the tunnel, and a temperature rise of about 100 kelvins in some of the affected magnets. Vacuum conditions in the beam pipe were also lost.<ref name = "BBCquench">{{cite web |url= http://news.bbc.co.uk/2/hi/science/nature/7626944.stm | title = Hadron Collider halted for months|publisher = BBC News}}</ref> It has been reported by CERN that the most likely cause of the problem was a faulty electrical connection between two magnets, and that it will take at least two months to fix it. Most of this delay is due to the time needed to warm up the affected sectors and then cool them back down to operating temperature.<ref name ="BBCquench"/><ref>"[http://press.web.cern.ch/press/PressReleases/Releases2008/PR09.08E.html CERN Press Release]"</ref> |
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In the original timeline of the LHC commissioning, the first "modest" high-energy collisions at a [[Center of mass frame|center-of-mass]] energy of 900 GeV were expected to take place before the end of September 2008, and the LHC was expected to be operating at 10 TeV by the time of the official inauguration on 21 October 2008.<ref>Henderson, Mark (18 September 2008) "[http://www.timesonline.co.uk/tol/news/uk/science/article4774817.ece ‘Big bang machine’ is back on collision course after its glitches are fixed]". ''Times Online''.</ref> However, due to the delay caused by the above-mentioned incident, the collider will not be operational again until spring 2009, after the winter shutdown which was anyway planned to start at the end of November 2008.<ref name="CERNPress2"/> In the meantime, the superconducting magnets will be trained<ref>{{cite web|url=http://www.fnal.gov/pub/ferminews/ferminews01-06-29/p4.html|title=Putting Memory to Work|publisher=Fermilab}}</ref> to work at the full current throughput, such that the 2009 run will start at the full 14 TeV design energy.<ref name="commissioning"/> |
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===Expected results=== |
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Once the supercollider is up and running, CERN scientists estimate that if the Standard Model is correct, a Higgs boson may be produced every few hours. At this rate, it may take up to three years to collect enough statistics unambiguously to discover the Higgs boson. Similarly, it may take one year or more before sufficient results concerning supersymmetric particles have been gathered to draw meaningful conclusions.<ref name="LHCbooklet"/> |
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==Proposed upgrade== |
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[[Image:Construction of LHC at CERN.jpg|upright|thumb|[[Compact Muon Solenoid|CMS]] detector for LHC]] |
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{{main|Super Large Hadron Collider}} |
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After some years of running, any [[particle physics]] experiment typically begins to suffer from [[diminishing returns]]; each additional year of operation discovers less than the year before. The way around the diminishing returns is to upgrade the experiment, either in energy or in [[luminosity]]. A luminosity upgrade of the LHC, called the [[Super Large Hadron Collider|Super LHC]], has been proposed,<ref>{{cite web|url=http://chep.knu.ac.kr/ICFA-Seminar/upload/9.29/Morning/session1/Ruggiero-ICFA-05.pdf|title=PDF presentation of proposed LHC upgrade|format=PDF}}</ref> to be made after ten years of LHC operation. The optimal path for the LHC luminosity upgrade includes an increase in the beam current (i.e., the number of protons in the beams) and the modification of the two high-luminosity interaction regions, ATLAS and CMS. To achieve these increases, the energy of the beams at the point that they are injected into the (Super) LHC should also be increased to {{nowrap|1 TeV}}. This will require an upgrade of the full pre-injector system, the needed changes in the [[Super Proton Synchrotron]] being the most expensive. |
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==Cost== |
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The total cost of the project is expected to be [[Euro|€]]3.2–6.4 billion.<ref name="TGPngm"/> The construction of LHC was approved in 1995 with a budget of {{nowrap|2.6 billion}} [[Swiss franc]]s {{nowrap|(€1.6 billion)}}, with another {{nowrap|210 million}} francs {{nowrap|(€140 million)}} towards the cost of the experiments. However, cost over-runs, estimated in a major review in 2001 at around {{nowrap|480 million}} francs {{nowrap|(€300 million)}} for the accelerator, and {{nowrap|50 million}} francs {{nowrap|(€30 million)}} for the experiments, along with a reduction in CERN's budget, pushed the completion date from 2005 to April 2007.<ref>{{cite web | url=http://user.web.cern.ch/User/LHCCost/2001-10-16/LHCCostReview.html | title=LHC Cost Review to Completion| last=Maiani | first=Luciano | accessdate=2001-01-15 | date=16 October 2001 | publisher=CERN }}</ref> |
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The superconducting magnets were responsible for 180 million francs ({{nowrap|€120 million}}) of the cost increase. There were also engineering difficulties encountered while building the underground cavern for the [[Compact Muon Solenoid]], in part due to [[#Construction accidents and delays|faulty parts]] loaned to CERN by fellow laboratories [[Argonne National Laboratory]], [[Fermilab]], and [[KEK]].<ref>{{cite journal | last=Feder | first=Toni | year=2001 | month=December | accessdate=2007-01-15 | title=CERN Grapples with LHC Cost Hike | journal=[[Physics Today]] | volume=54 | issue=12 | pages=21 | url=http://www.aip.org/pt/vol-54/iss-12/p21b.html | doi=10.1063/1.1445534 }}</ref> |
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[[David King (scientist)|David King]], the former Chief Scientific Officer for the United Kingdom, has criticised the LHC for taking a higher priority for funds than solving the Earth's major challenges; principally [[climate change]], but also [[population growth]] and [[poverty in Africa]].<ref>{{cite web|url =http://news.bbc.co.uk/1/hi/sci/tech/7603257.stm | first = Jonathan |last = Amostitle |title = 'Climate crisis' needs brain gain |publisher =[[BBC]] |date =8 September 2008}}</ref> |
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==Computing resources== |
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The [[LHC Computing Grid]] is being constructed to handle the massive amounts of data produced by the Large Hadron Collider. It incorporates both private fiber optic cable links and existing high-speed portions of the public Internet, enabling data transfer from CERN to academic institutions around the world. |
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The [[distributed computing]] project [[LHC@home]] was started to support the construction and calibration of the LHC. The project uses the [[Berkeley Open Infrastructure for Network Computing|BOINC]] platform, enabling everybody with an internet connection to have scientific projects use their computer idle time, to simulate how particles will travel in the tunnel. With this information, the scientists will be able to determine how the magnets should be calibrated to gain the most stable "orbit" of the beams in the ring. |
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==Safety of particle collisions== |
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{{main|Safety of particle collisions at the Large Hadron Collider}} |
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The upcoming experiments at the Large Hadron Collider have sparked fears among the public that the LHC particle collisions might produce doomsday phenomena, including dangerous [[micro black hole|microscopic black hole]]s and [[strange matter]].<ref name="CosmicLog-2September2008">Boyle, Alan (2 September 2008). "[http://cosmiclog.msnbc.msn.com/archive/2008/09/02/1326534.aspx Courts weigh doomsday claims]". ''Cosmic Log''. msnbc.com.</ref> Two CERN-commissioned safety reviews have examined these concerns and concluded that the experiments at the LHC present no danger and that there is no reason for concern,<ref name="2003SafetyReport">Blaizot JP, Iliopoulos J, Madsen J, Ross G, Sonderegger P, Specht H (2003). ''[http://doc.cern.ch/yellowrep/2003/2003-001/p1.pdf Study of Potentially Dangerous Events During Heavy-Ion Collisions at the LHC]''. CERN. Geneva. [http://cdsweb.cern.ch/search?sysno=002372601cer CERN-2003-001].</ref><ref name="LSAGreport">Ellis J, Giudice G, Mangano ML, Tkachev I, Wiedemann U (LHC Safety Assessment Group) (5 September 2008). "[http://www.iop.org/EJ/article/0954-3899/35/11/115004/g8_11_115004.pdf?request-id=1973667e-34da-47a4-b75a-08624558a81b Review of the Safety of LHC Collisions]". ''''[[Journal of Physics G: Nuclear and Particle Physics]]''. 35, 115004 (18pp). [[doi:10.1088/0954-3899/35/11/115004]]. [http://cdsweb.cern.ch/record/1111112?ln=fr CERN record]. [[arXiv:0806.3414]].</ref><ref name=SummarySafety>"[http://public.web.cern.ch/public/en/LHC/Safety-en.html The safety of the LHC]". CERN 2008 (CERN website).</ref> a conclusion expressly endorsed by the [[American Physical Society]], the world's second largest organization of physicists.<ref name="APS-Statement">"[http://www.aps.org/units/dpf/governance/reports/upload/lhc_saftey_statement.pdf Statement by the Executive Committee of the DPF on the Safety of Collisions at the Large Hadron Collider]" issued by the [http://www.aps.org/units/dpf/ Division of Particles & Fields] (DPF) of the [[American Physical Society]] (APS)</ref> |
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==Operational challenges== |
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The size of the LHC constitutes an exceptional engineering challenge with unique operational issues on account of the huge energy stored in the magnets and the beams.<ref name="irfu1"/><ref>{{cite web|url=http://lhc.web.cern.ch/lhc/general/acphys.htm|title=Challenges in accelerator physics}}</ref> While operating, the total [[Superconducting magnetic energy storage|energy stored in the magnets]] is {{nowrap| [[Orders of magnitude (energy)#1E9|10]] [[gigajoule|GJ]]}} (equivalent to one and a half [[Barrel of oil equivalent|barrels of oil]] or 2.4 [[TNT equivalent|tons of TNT]]) and the total energy carried by the two beams reaches {{nowrap|[[Orders of magnitude (energy)#1E6|724]] [[joule|MJ]]}} (about a tenth of a barrel of oil, or half a lightning bolt).<ref>{{cite web|url=https://edms.cern.ch/file/445830/5/Vol_1_Chapter_2.pdf|title=Beam Parameters and Definitions}}</ref> |
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Loss of only one ten-millionth part (10<sup>−7</sup>) of the beam is sufficient to [[superconducting magnet#Magnet quench|quench]] a [[superconducting magnet]], while the [[beam dump]] must absorb [[Orders of magnitude (energy)#1E6|362]] MJ, an energy equivalent to that of burning eight kilograms of oil, for each of the two beams. These immense energies are even more impressive considering how little matter is carrying it: under nominal operating conditions (2,808 bunches per beam, 1.15×10<sup>11</sup> protons per bunch), the beam pipes contain 1.0×10<sup>-9</sup> gram of hydrogen, which, in [[standard conditions for temperature and pressure]], would fill the volume of one grain of fine sand. |
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On August 10, 2008, a group of hackers calling themselves the Greek Security Team defaced a website at CERN, criticizing their computer security. There was no access to the control network of the collider.<ref>http://it-support-servicestatus.web.cern.ch/it-support-servicestatus/IncidentArchive/080915-CMSMON.htm</ref> |
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==Construction accidents and delays== |
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* On 25 October 2005, a technician was killed in the LHC tunnel when a crane load was accidentally dropped.<ref>{{cite press release |title=Message from the Director-General |publisher=CERN |date=26 October 2005 |accessdate=2007-01-15 |url=http://user.web.cern.ch/user/QuickLinks/Announcements/2005/Accident.html and French}}</ref> |
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*On 27 March 2007 a cryogenic magnet support broke during a pressure test involving one of the LHC's inner triplet (focusing quadrupole) magnet assemblies, provided by [[Fermilab]] and [[KEK]]. No one was injured. Fermilab director Pier Oddone stated "In this case we are dumbfounded that we missed some very simple balance of forces". This fault had been present in the original design, and remained during four engineering reviews over the following years.<ref>{{cite web|url=http://www.photonics.com/content/news/2007/April/4/87089.aspx |title=Fermilab'Dumbfounded'by fiasco that broke magnet}}</ref> Analysis revealed that its design, made as thin as possible for better insulation, was not strong enough to withstand the forces generated during pressure testing. Details are available in a statement from Fermilab, with which CERN is in agreement.<ref>{{cite web|url=http://user.web.cern.ch/user/QuickLinks/Announcements/2007/LHCInnerTriplet_5.html|title=LHC Magnet Test Failure}}</ref><ref>{{cite web|url=http://www.fnal.gov/pub/today/lhc_magnet_archive.html|title=Updates on LHC inner triplet failure}}</ref> Repairing the broken magnet and reinforcing the eight identical assemblies used by LHC delayed the startup date,<ref>{{cite web |url=http://www.bbc.co.uk/sn/tvradio/programmes/horizon/broadband/tx/universe/highlights/ |title=The God Particle|accessdate=2007-05-22|work=www.bbc.com}}</ref> then planned for November 2007. |
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* Problems with a magnetic [[Superconducting magnet#Magnet quench|quench]] on September 19, 2008, caused a leak of a tonne of liquid helium, and has delayed the operation for several months.<ref>http://news.bbc.co.uk/2/hi/in_depth/7632408.stm</ref> Since the repairs are scheduled to be finished around late November, this conflicts into the winter shutdown, meaning initial experiments will not take place until Spring 2009. |
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==In popular culture== |
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<!-- Deleted image removed: [[Image:Lhc27.jpg|thumb|Aerial view of CERN and the surrounding region of Switzerland and France]] --> |
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<!-- This is not a trivia list! Please write prose and include notable occurrences. A good measure of notability would be third-party coverage or a response by CERN, for example Angels and Demons. Your favorite webcomic probably does not meet this standard, not even xkcd. --> |
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The Large Hadron Collider was featured in ''[[Angels & Demons]]'' by [[Dan Brown]], which involves dangerous [[antimatter]] created at the LHC used as a weapon against the Vatican. CERN published a "Fact or Fiction?" page discussing the accuracy of the book's portrayal of the LHC, CERN, and particle physics in general.<ref>{{cite web |url=http://public.web.cern.ch/Public/en/Spotlight/SpotlightAandD-en.html |title=Angels and Demons |accessdate=2008-07-16 |work= |publisher=CERN}}</ref> The [[Angels & Demons (film)|movie version]] of the book has footage filmed on-site at one of the experiments at the LHC; the director, [[Ron Howard]], met with CERN experts in an effort to make the science in the story more accurate.<ref>{{cite web |url=http://atlas-service-enews.web.cern.ch/atlas-service-enews/news/news_angelphoto.php |title=ATLAS gets the Hollywood treatment |accessdate=2008-07-16 |work=ATLAS e-News |publisher=CERN |date= |last=Perkins |first=Ceri}}</ref> |
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CERN employee [[Katherine McAlpine]]'s "Large Hadron Rap"<ref>{{cite web|url=http://www.youtube.com/watch?v=j50ZssEojtM |title=YouTube - Large Hadron Rap |publisher=Youtube.com |date= |accessdate=2008-09-09}}</ref> surpassed three million YouTube views on 15 September 2008.<ref>{{cite web|url=https://www.msu.edu/~mcalpin9/lhc_rap/largehadron.html|title=Large Hadron Rap links and lyrics}}</ref><ref name="Telegraph02/09/2008">"[http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2008/08/26/scirap126.xml Rap about world's largest science experiment becomes YouTube hit]". ''Telegraph''. Last Updated: 2 September 2008</ref><ref>Bogo, Jennifer (1 August 2008). "[http://www.popularmechanics.com/blogs/science_news/4276090.html Large Hadron Collider Rap Teaches Particle Physics in 4 Minutes]". ''Popular Mechanics''.</ref> |
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[[BBC Radio 4]] commemorated the switch-on of the LHC on 10 September 2008 with "Big Bang Day".<ref>{{cite web |url=http://www.bbc.co.uk/radio4/bigbang/ |title=BBC - Radio 4 - Big Bang Day |accessdate=2008-09-11 |publisher=[[BBC]] |date=2008-09-10 }}</ref> Included in this event was a radio episode of the TV series ''[[Torchwood]]'', with a plot involving the LHC, entitled ''[[Lost Souls (Torchwood)|Lost Souls]]''.<ref>{{cite web |url=http://www.bbc.co.uk/pressoffice/pressreleases/stories/2008/08_august/07/cern2.shtml |title=Programming for Big Bang Day on BBC Radio 4 |accessdate=2008-08-11 |publisher=BBC Press Office}}<br/>{{cite web |url=http://www.bbc.co.uk/radio4/bigbang/ |title=Radio 4 - Big Bang Day |accessdate=2008-09-10 |publisher=BBC}}<br/>{{cite news |first=Paul |last=Donovan |title=The BBC has Big Bang to rights |url=http://entertainment.timesonline.co.uk/tol/arts_and_entertainment/tv_and_radio/article4669278.ece |work=[[The Sunday Times]] |date=2008-09-07 |accessdate=2008-09-11 }}</ref> CERN's director of communications, James Gillies, commented, "The CERN of reality bears little resemblance to that of [[Joseph Lidster]]'s Torchwood script."<ref>{{cite web |url=http://www.bbc.co.uk/radio4/bigbang/sciencefiction.shtml |title=CERN in Science-Fiction |accessdate=2008-09-11 |last=Gillies |first=James |work=[[BBC Radio 4]] website |publisher=[[BBC]]}}</ref> |
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<!-- This is not a trivia list; please see the comment at the top of this section. --> |
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==References== |
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'''Notes''' |
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{{reflist|2}} |
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{{commons|Large Hadron Collider}} |
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==External links== |
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<div style="-moz-column-count:2; column-count:2;"> |
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*{{official|http://lhc.web.cern.ch/lhc/}} |
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* {{Citation |title=LHC Machine |url=http://www.iop.org/EJ/journal/-page=extra.lhc/jinst |author=Lyndon Evans and Philip Bryant (editors) |journal=Journal of Instrumentation |date=2008-08-14 |volume=3 |issue=S08001 |doi=10.1088/1748-0221/3/08/S08001 |pages=S08001 }}. Full documentation for design and construction of the LHC and its six detectors (1600 p). |
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*[http://lhc-milestones.web.cern.ch/LHC-Milestones/default.html Official Timeline of LHC Milestones] |
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*[http://www.ted.com/talks/view/id/253 TED talks (video) - Brian Cox: What really goes on at the Large Hadron Collider] |
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*[http://public.web.cern.ch/public/en/LHC/LHC-en.html Overview of the LHC at CERN's public webpage] |
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*[http://www.petermccready.com/portfolio/05091901.html ATLAS Experiment] - Virtual Reality photography panoramas |
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*[http://news.bbc.co.uk/1/hi/sci/tech/4524132.stm Energising the quest for 'big theory'] |
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*[http://www.symmetrymagazine.org/cms/?pid=1000350 ''symmetry'' magazine LHC special issue August 2006], [http://www.symmetrymagazine.org/cms/?pid=1000562 special issue December 2007] |
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*[http://www.bbc.co.uk/sn/tvradio/programmes/horizon/broadband/tx/universe/ BBC Horizon, The six billion dollar experiment] |
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*[[The New Yorker|New Yorker]]: [http://www.newyorker.com/reporting/2007/05/14/070514fa_fact_kolbert Crash Course]. The world’s largest particle accelerator. |
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*[[New York Times|NYTimes]]: [http://www.nytimes.com/2007/05/15/science/15cern.html?ex=1336881600&en=7825f6702d7071e7&ei=5090&partner=rssuserland&emc=rss A Giant Takes On Physics’ Biggest Questions]. |
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*[http://www.ingenia.org.uk/ingenia/articles.aspx?index=489 Large Hadron Collider, ''Ingenia'' magazine] |
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*[http://www2.cnrs.fr/en/1249.htm Birth of a Giant, ''CNRS'' magazine] |
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*[http://seedmagazine.com/news/2006/07/why_a_large_hadron_collider.php Why a Large Hadron Collider?] ''[[Seed Magazine]]'' interviews with physicists. |
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</div> |
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{{CERN}} |
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[[Category:Ain]] |
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[[Category:Canton of Geneva]] |
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[[Category:Large Hadron Collider| ]] |
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[[Category:Particle physics facilities]] |
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[[Category:E-Science]] |
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[[af:Groot Hadron-versneller]] |
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[[ar:مصادم الهدرونات الكبير]] |
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[[be-x-old:Вялікі гадронны калідэр]] |
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[[bg:Голям адронов ускорител]] |
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[[ca:LHC]] |
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[[cs:Large Hadron Collider]] |
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[[da:Large Hadron Collider]] |
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[[de:Large Hadron Collider]] |
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[[el:LHC]] |
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[[es:Gran colisionador de hadrones]] |
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[[eo:Granda Koliziiganto de Hadronoj]] |
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[[fa:برخورددهنده هادرونی بزرگ]] |
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[[fr:Large Hadron Collider]] |
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[[gl:Gran colisionador de hadróns]] |
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[[ko:거대 하드론 충돌기]] |
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[[hi:लार्ज हैड्रान कोलाइडर]] |
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[[id:Penumbuk Hadron Raksasa]] |
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[[ia:LHC]] |
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[[is:Stóri sterkeindahraðallinn]] |
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[[it:Large Hadron Collider]] |
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[[he:מאיץ LHC]] |
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[[kn:ಲಾರ್ಜ್ ಹ್ಯಾಡ್ರಾನ್ ಕೊಲೈಡರ್]] |
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[[kk:Үлкен адрондар соқтығыстырушысы]] |
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[[ht:Large Hadron Collider]] |
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[[la:Collisor Hadronalis Magnus]] |
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[[lv:Lielais hadronu kolaiders]] |
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[[lt:Didysis hadronų priešpriešinių srautų greitintuvas]] |
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[[hu:Nagy Hadronütköztető]] |
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[[ml:ലാര്ജ് ഹാഡ്രോണ് കൊളൈഡര്]] |
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[[nl:Large Hadron Collider]] |
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[[ja:大型ハドロン衝突型加速器]] |
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[[no:Large Hadron Collider]] |
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[[nn:Large Hadron Collider]] |
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[[pl:Wielki Zderzacz Hadronów]] |
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[[pt:Grande Colisor de Hádrons]] |
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[[ro:Large Hadron Collider]] |
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[[ru:Большой адронный коллайдер]] |
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[[sq:Përplasësi i Madh i Hadroneve]] |
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[[scn:Large Hadron Collider]] |
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[[simple:Large Hadron Collider]] |
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[[sk:Veľký hadrónový urýchľovač]] |
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[[sl:Veliki hadronski trkalnik]] |
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[[fi:Large Hadron Collider]] |
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[[sv:Large Hadron Collider]] |
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[[ta:பெரும் ஹாட்ரான் மோதி]] |
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[[th:เครื่องเร่งอนุภาคขนาดใหญ่]] |
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[[vi:Large Hadron Collider]] |
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[[tr:Büyük Hadron Çarpıştırıcısı]] |
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[[uk:Великий адронний колайдер]] |
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[[zh:大型強子對撞器]] |
Revision as of 18:54, 5 October 2008
WE WILL DIE!!!!