Saswat Parida

CONTENTS I. ABSTRACT II. LIST OF FIGURES III. LIST O F TABLES INTRODUCTION HISTORY OPERATIONAL HISTORY FIGURES & STRUCTURAL DIAGRAMS LITERATURE SURVEY DISCUSSION CONSTRUCTION & WORKING PRINCIPLE OPERATIONAL CHALLENGES ADVANTAGES DISADVANTAGES APPLICATIONS CONCLUSION REFERENCES LIST OF FIGURES ABSTRACT The Large Hadron Collider (LHC) is the world's largest and most powerful particle collider, the largest, most complex experimental facility ever built, and the largest single machine in the world. It was built by the European Organization for Nuclear Research (CERN) between 1998 and 2008 in collaboration with over 10,000 scientists and engineers from over 100 countries, as well as hundreds of universities and laboratories. It lies in a tunnel 27 kilometres (17 mi) in circumference, as deep as 175 metres (574 ft) beneath the France–Switzerland border near Geneva, Switzerland. The LHC's aim is to allow physicists to test the predictions of different theories of particle physics, high-energy physics and in particular, to further test the properties of the Higgs boson and the large family of new particles predicted by supersymmetric theories, and other unsolved questions of physics, advancing human understanding of physical laws. It contains seven detectors, each designed for certain kinds of research. The proton-proton collision is the primary operation method, but the LHC has also collided protons with lead nuclei for two months in 2013 and used lead–lead collisions for about one month each in 2010, 2011, and 2013 for other investigations. TABLE OF CONTENTS LIST OF FIGURES LIST OF TABLES CHAPTER-1 INTRODUCTION The Large Hadron Collider (LHC) is the world's largest and most powerful particle collider, the largest, most complex experimental facility ever built, and the largest single machine in the world. It was built by the European Organization for Nuclear Research (CERN) between 1998 and 2008 in collaboration with over 10,000 scientists and engineers from over 100 countries, as well as hundreds of universities and laboratories. It lies in a tunnel 27 kilometres (17 mi) in circumference, as deep as 175 metres (574 ft) beneath the France–Switzerland border near Geneva, Switzerland. The Large Hadron Collider is the world's largest and most powerful particle collider ever built. The term hadron refers to composite particles composed of quarks(subatomic particles carrying a fractional electric charge) held together by the strong force. The best-known hadrons are the baryons(composite subatomic particle made up of three quarks) protons and neutrons. A collider is a type of a particle accelerator with two directed beams of particles. In particle physics, colliders are used as a research tool: they accelerate particles to very high kinetic energies and let them impact other particles. HISTORY It was designed by CERN to handle the significant volume of data produced by LHC experiments.It was built by the European Organization for Nuclear Research between 1998 and 2008 in collaboration with over 10,000 scientists and engineers.It lies in a tunnel 27 kilometers in circumference, as deep as 175 meters beneath the France–Switzerland border near Geneva, Switzerland. Its first research run took place from 30 March 2010 to 13 February 2013.With a budget of 7.5 billion euros , the LHC is one of the most expensive scientific instruments ever built. Its first research run took place from 30 March 2010 to 13 February 2013 at an initial energy of 3.5 teraelectronvolts (TeV) per beam (7 TeV total), almost 4 times more than the previous world record for a collider,rising to 4 TeV per beam (8 TeV total) from 2012.On 13 February 2013 the LHC's first run officially ended, and it was shut down for planned upgrades. 'Test' collisions restarted in the upgraded collider on 5 April 2015, reaching 6.5 TeV per beam on 20 May 2015 (13 TeV total, the current world record for particle collisions). Its second research run commenced on schedule, on 3 June 2015. OPERATIONAL HISTORY The LHC first went live on 10 September 2008, but initial testing was delayed for 14 months from 19 September 2008 to 20 November 2009, following a magnet quench incident that caused extensive damage to over 50 superconducting magnets, their mountings, and the vacuum pipe. During its first run (2010 - 2013) the LHC collided two opposing particle beams of either protons at up to 4 teraelectronvolts (4 TeV or 0.64 microjoules), or lead nuclei (574 TeV per nucleus, or 2.76 TeV per nucleon).[30][52] Its first run discoveries included a particle thought to be the long sought Higgs boson, several composite particles (hadrons) like the χb (3P) bottomonium state, the first creation of a quark–gluon plasma, and the first observations of the very rare decay of the Bs meson into two muons (Bs0 → μ+μ−), which challenged the validity of existing models of supersymmetry. FIGURES & STRUCTURAL DIAGRAMS Location Large Hadron Collider The 2-in-1 structure of the LHC dipole magnets Different types of detectors: CHAPTER-2 LITERATURE SURVEY It is generally used for testing the predictions of different theories of particle physics(branch of physics that studies the nature of the particles that constitute matter and radiation , high-energy physics and to prove or disprove the existence of large family of new particles and other unsolved questions of physics).It contains seven detectors-ATLAS ,CMS ,ALICE , LHCB ,TOTEM, MOEDAL and LHCF which are generally used for proton-proton collision and lead–lead collisions. Physicists hope that the LHC will help answer some of the fundamental open questions in physics, concerning the basic laws governing the interactions and forces among the elementary objects, the deep structure of space and time, and in particular the interrelation between quantum mechanics and general relativity, where current theories and knowledge are unclear or break down altogether. Data is also needed from high energy particle experiments to suggest which versions of current scientific models are more likely to be correct – in particular to choose between the Standard Model and Higgsless models and to validate their predictions and allow further theoretical development. Many theorists expect new physics beyond the Standard Model to emerge at the TeV energy level, as the Standard Model appears to be unsatisfactory. Issues possibly to be explored by LHC collisions include: Are the masses of elementary particles actually generated by the Higgs mechanism via electroweak symmetry breaking? It is expected that the collider will either demonstrate or rule out the existence of the elusive Higgs boson, thereby allowing physicists to consider whether the Standard Model or its Higgsless alternatives are more likely to be correct. Is supersymmetry, an extension of the Standard Model and Poincaré symmetry, realized in nature, implying that all known particles have supersymmetric partners? Are there extra dimensions,as predicted by various models based on string theory, and can we detect them? What is the nature of the dark matter that appears to account for 27% of the mass-energy of the universe? Other open questions that may be explored using high energy particle collisions: It is already known that electromagnetism and the weak nuclear force are different manifestations of a single force called the electroweak force. The LHC may clarify whether the electroweak force and the strong nuclear force are similarly just different manifestations of one universal unified force, as predicted by various Grand Unification Theories. Why is the fourth fundamental force (gravity) so many orders of magnitude weaker than the other three fundamental forces? Are there additional sources of quark flavour mixing, beyond those already present within the Standard Model? Why are there apparent violations of the symmetry between matter and antimatter? See also CP violation. What are the nature and properties of quark–gluon plasma, thought to have existed in the early universe and in certain compact and strange astronomical objects today? This will be investigated by heavy ion collisions, mainly in ALICE, but also in CMS and ATLAS. Findings published in 2012 confirmed the phenomenon of jet quenching in heavy-ion collisions, and was first observed in 2010. CHAPTER-3 DISCUSSION CONSTRUCTION & WORKING PRINCIPLE : DESIGN : The LHC is the world's largest and highest-energy particle accelerator.The collider is contained in a circular tunnel, with a circumference of 27 kilometres (17 mi), at a depth ranging from 50 to 175 metres (164 to 574 ft) underground.The 3.8-metre (12 ft) wide concrete-lined tunnel, constructed between 1983 and 1988, was formerly used to house the Large Electron–Positron Collider. 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. The collider tunnel contains two adjacent parallel beamlines (or beam pipes) that intersect at four points, each containing a beam, which travel in opposite directions around the ring. Some 1,232 dipole magnets keep the beams on their circular path , while an additional 392 quadrupole magnets 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 cross. In total, over 1,600 superconducting magnets are installed, with most weighing over 27 tonnes. Approximately 96 tonnes of superfluid helium 4 is needed to keep the magnets, made of copper-clad niobium-titanium, at their operating temperature of 1.9 K (−271.25 °C), making the LHC the largest cryogenic facility in the world at liquid helium temperature. A Feynman diagram of one way the Higgs boson may be produced at the LHC. Here, two quarks each emit a W or Z boson, which combine to make a neutral Higgs: When running at full design energy of 7 TeV per beam, once or twice a day, as the protons are accelerated from 450 GeV to 7 TeV, the field of the superconducting dipole magnets will be increased from 0.54 to 8.3 teslas (T). The protons will each have an energy of 7 TeV, giving a total collision energy of 14 TeV. At this energy the protons have a Lorentz factor of about 7,460 and move at about- c, or about 2.7 metres per second (6 mph) slower than the speed of light. The 2-in-1 structure of the LHC dipole magnets: It will take less than 90 microseconds (μs) for a proton to travel once around the main ring – a speed of about 11,000 revolutions per second. Rather than continuous beams, the protons will be bunched together, into up to 2,808 bunches, with 115 billion protons in each bunch so that interactions between the two beams will take place at discrete intervals, mainly 25 nanoseconds (ns) apart, providing a bunch collision rate of 40 MHz . However it will be operated with fewer bunches when it is first commissioned, giving it a bunch crossing interval of 75 ns. The design luminosity of the LHC is 1034 cm−2s−1. 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 50-MeV protons, which feeds the Proton Synchrotron Booster (PSB). There the protons are accelerated to 1.4 GeV and injected into the Proton Synchrotron (PS), where they are accelerated to 26 GeV. Finally the Super Proton Synchrotron (SPS) is used to further increase their energy to 450 GeV before they are at last injected (over a period of several minutes) into the main ring. Here the proton bunches are accumulated, accelerated (over a period of 20 minutes) to their peak energy, and finally circulated for 5 to 24 hours while collisions occur at the four intersection points. The LHC physics program is mainly based on proton–proton collisions. However, shorter running periods, typically one month per year, with heavy-ion collisions are included in the program. While lighter ions are considered as well, the baseline scheme deals with lead ions (see A Large Ion Collider Experiment). The lead ions are first accelerated by the linear accelerator LINAC 3, and the Low-Energy Ion Ring (LEIR) is used as an ion storage and cooler unit. The ions are then further accelerated by the PS and SPS before being injected into LHC ring, where they reached an energy of 1.58 TeV per nucleon (or 328 TeV per ion), higher than the energies reached by the Relativistic Heavy Ion Collider. The aim of the heavy-ion program is to investigate quark–gluon plasma, which existed in the early universe. Detectors: Seven 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 detectors. ALICE and LHCb have more specific roles and the last three, TOTEM, MoEDAL and LHCf, are very much smaller and are for very specialized research. ATLAS One of two general purpose detectors. ATLAS will be used to look for signs of new physics, including the origins of mass and extra dimensions CMS The other general purpose detector will, like ATLAS, hunt for the Higgs boson and look for clues to the nature of dark matter ALICE ALICE is studying a "fluid" form of matter called quark–gluon plasma that existed shortly after the Big Bang. LHCb Equal amounts of matter and antimatter were created in the Big Bang. LHCb will try to investigate what happened to the "missing" antimatter TABLE - 1 . Description: . Computing and analysis facilities Data produced by LHC, as well as LHC-related simulation, was estimated at approximately 15 petabytes per year (max throughput while running not stated)[41] - a major challenge in its own right at the time. The LHC Computing Grid was constructed as part of the LHC design, to handle the massive amounts of data expected for its collisions. It is an international collaborative project that consists of a grid-based computer network infrastructure initially connecting 140 computing centers in 35 countries (over 170 in 36 countries as of 2012). It incorporates both private fiber optic cable links and existing high-speed portions of the public Internet to enable data transfer from CERN to academic institutions around the world. The Open Science Grid is used as the primary infrastructure in the United States, and also as part of an interoperable federation with the LHC Computing Grid. The distributed computing project LHC@home was started to support the construction and calibration of the LHC. The project uses the BOINC platform, enabling anybody with an Internet connection and a computer running Mac OS X, Windows or Linux, to use their computer's 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.[44] In August 2011, a second application went live (Test4Theory) which performs simulations against which to compare actual test data, to determine confidence levels of the results. By 2012 data from over 6 quadrillion (6 x 1015) LHC proton-proton collisions had been analyzed, LHC collision data was being produced at approximately 25 petabytes per year, and the LHC Computing Grid had become the world's largest computing grid (as of 2012), comprising over 170 computing facilities in a worldwide network across 36 countries. Basic diagram of a LARGE HADRON COLLIDER: Operational challenges: The size of the LHC constitutes an exceptional engineering challenge with unique operational issues on account of the amount of energy stored in the magnets and the beams.While operating, the total energy stored in the magnets is 10 GJ (2,400 kilograms of TNT) and the total energy carried by the two beams reaches 724 MJ (173 kilograms of TNT).Loss of only one ten-millionth part (10−7) of the beam is sufficient to quench a superconducting magnet, while each of the two beam dumps must absorb 362 MJ (87 kilograms of TNT). These energies are carried by very little matter: under nominal operating conditions (2,808 bunches per beam, 1.15×1011 protons per bunch), the beam pipes contain 1.0×10−9 gram of hydrogen, which, in standard conditions for temperature and pressure, would fill the volume of one grain of fine sand. Construction accidents and delays: On 25 October 2005, José Pereira Lages, a technician, was killed in the LHC when a switchgear that was being transported fell on him. On 27 March 2007 a cryogenic magnet support designed and provided by Fermilab and KEK broke during an initial pressure test involving one of the LHC's inner triplet (focusing quadrupole) magnet assemblies. 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. 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. Repairing the broken magnet and reinforcing the eight identical assemblies used by LHC delayed the startup date, then planned for November 2007. On 19 September 2008, during initial testing, a faulty electrical connection led to a magnet quench (the sudden loss of a superconducting magnet's superconducting ability due to warming or electric field effects). Six tonnes of supercooled liquid helium - used to cool the magnets - escaped, with sufficient force to break 10-ton magnets nearby from their mountings, and caused considerable damage and contamination of the vacuum tube (see 2008 quench incident); repairs and safety checks caused a delay of around 14 months.Two vacuum leaks were identified in July 2009, and the start of operations was further postponed to mid-November 2009. TABLE - 2 Timeline of operations Date Event 10 Sep 2008 CERN successfully fired the first protons around the entire tunnel circuit in stages. 19 Sep 2008 Magnetic quench occurred in about 100 bending magnets in sectors 3 and 4, causing a loss of approximately 6 tonnes of liquid helium. 30 Sep 2008 First "modest" high-energy collisions planned but postponed due to accident. 16 Oct 2008 CERN released a preliminary analysis of the accident. 21 Oct 2008 Official inauguration. 5 Dec 2008 CERN released detailed analysis. 20 Nov 2009 Low-energy beams circulated in the tunnel for the first time since the accident. 23 Nov 2009 First particle collisions in all four detectors at 450 GeV. 30 Nov 2009 LHC becomes the world's highest-energy particle accelerator achieving 1.18 TeV per beam, beating the Tevatron's previous record of 0.98 TeV per beam held for eight years. 15 Dec 2009 First scientific results, covering 284 collisions in the ALICE detector. 28 Feb 2010 The LHC continues operations ramping energies to run at 3.5 TeV for 18 months to two years, after which it will be shut down to prepare for the 14 TeV collisions (7 TeV per beam) 30 Mar 2010 The two beams collided at 7 TeV (3.5 TeV per beam) in the LHC at 13:06 CEST, marking the start of the LHC research program. 8 Nov 2010 Start of the first run with lead ions. 6 Dec 2010 End of the run with lead ions. Shutdown until early 2011. 13 Mar 2011 Beginning of the 2011 run with proton beams. 21 Apr 2011 LHC becomes the world's highest-luminosity hadron accelerator achieving a peak luminosity of 4.67·1032 cm−2s−1, beating the Tevatron's previous record of 4·1032 cm−2s−1 held for one year. 24 May 2011 Quark–gluon plasma achieved. 17 Jun 2011 The high luminosity experiments ATLAS and CMS reach 1 fb−1 of collected data. 14 Oct 2011 LHCb reaches 1 fb−1 of collected data. 23 Oct 2011 The high luminosity experiments ATLAS and CMS reach 5 fb−1 of collected data. Nov 2011 Second run with lead ions. 22 Dec 2011 First new composite particle discovery, the χb (3P) bottomonium meson, observed with proton-proton collisions in 2011. 5 Apr 2012 First collisions with stable beams in 2012 after the winter shutdown. The energy is increased to 4 TeV per beam (8 TeV in collisions). 4 Jul 2012 First new elementary particle discovery, a new boson observed that is "consistent with" the theorized Higgs boson. (This has now been confirmed as the Higgs boson itself. 8 Nov 2012 First observation of the very rare decay of the Bs meson into two muons (Bs0 → μ+μ−), a major test of supersymmetry theories, shows results at 3.5 sigma that match the Standard Model rather than many of its super-symmetrical variants. 20 Jan 2013 Start of the first run colliding protons with Lead ions. 11 Feb 2013 End of the first run colliding protons with Lead ions. 14 Feb 2013 Beginning of the first long shutdown, to prepare the collider for a higher energy and luminosity. When reactivated in 2015, the LHC will operate with an energy of 6.5 TeV per proton. 7 Mar 2015 Injection tests for Run 2 send protons towards LHCb & ALICE 5 Apr 2015 Both beams circulated in the collider. Four days later, a new record energy of 6.5 TeV per proton was achieved 20 May 2015 Protons collided in the LHC at the record-breaking energy of 13 TeV 3 June 2015 Start of delivering the physics data after almost two years offline for re-commissioning.[ ADVANTAGES The LHC Computing Grid (project that consists of a grid-based computer network to handle the prodigious volume of data produced by Large Hadron Collider) was constructed as part of the LHC design, to handle the massive amounts of data expected for its collisions. It is used as the primary infrastructure in the United States, and also as part of an interoperable federation with the LHC Computing Grid. It determines how the magnets should be calibrated to gain the most stable "orbit" of the beams in the ring. The Large Hadron Collider gained a considerable amount of attention from outside the scientific community and its progress is followed by most popular science media. The LHC has also inspired works of fiction including novels, TV series, video games and films. DISADVANTAGES The size of the LHC constitutes an exceptional engineering challenge with unique operational issues on account of the amount of energy stored in the magnets and the beams. While operating, the total energy lost is nearly 10 Giga Joules and the total energy carried by the two beams reaches 724 MJ. With a budget of 7.5 billion euros, the LHC is one of the most expensive scientific instruments ever built. APPLICATIONS The optimal path for the LHC luminosity upgrade includes an increase in the beam current (i.e. the number of particles 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 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. Currently the collaborative research effort of LHC Accelerator Research Program, LARP, is conducting research into how to achieve these goals. The accelerator physics developed to do high energy physics has greatly increased the ability to focus a beam of energetic particles into a very small area, as well as the ability to cause the particles to interact only at the location of the cancer instead of entirely along the path of the particle beam. Fermilab, another high energy physics facility, runs a neutron cancer therapy center that has treated 3,000 patients since 1976. Most focused radiation cancer therapy has its roots in accelerator physics. Accelerator physics has also led to cleaner manufacturing. For example, the process by which rubber is vulcanized to produce tires was historically done entirely via the application of some truly nasty chemicals. Now, beams from low energy accelerators are used to vulcanize the rubber, significantly decreasing the chemicals required. Some of the first pattern recognition algorithms were developed to recognize particle tracks in images of interactions. Pattern recognition has taken on a research life of its own, but some of the most basic algorithms came from particle physics (for example, the Hough transform). Researchers at the Tevatron (the predecessor to the LHC) and the LHC have contributed significantly to grid computing. Experiments at the LHC produce tens of petabytes of data/year, which must be processed, stored, and distributed to physicists around the world via a computing grid. CONCLUSION So its quiet clear that the CERN studies about the FUNDAMENTAL PARTICLES – the basic particles . Its point is to solve some unknown questions about the universe and to re-create the conditions after the BIG BANG . Then it will also be possible to see what will happen to the universe later . We do not know how long the experiment will last since no one has ever done it before. It might last for years. Black holes are one of the most fascinating objects in the Universe: nothing can escape from their attraction, not even light! So by the help of LHC, we might even create artificially mini Black Holes, for example if there are new space-time dimensions. The experiments at the Large Hadron Collider sparked fears that the particle collisions might produce doomsday phenomena, involving the production of stable microscopic black holes or the creation of hypothetical particles called strangelets. The Large Hadron Collider gained a considerable amount of attention from outside the scientific community and its progress is followed by most popular science media. The LHC has also inspired works of fiction including novels, TV series, video games and films. REFERENCES https://en.wikipedia.org/wiki/Large_Hadron_Collider https://en.wikipedia.org/wiki/File:The_2-in-1_structure_of_the_LHC_dipole_magnets.jpg https://en.wikipedia.org/wiki/File:BosonFusion-Higgs.svg https://en.wikipedia.org/wiki/Collider http://www.slideshare.net/