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The Large (LHC) is the most powerful par- ticle accelerator ever built. The accelerator sits in a tunnel 100 metres underground at CERN, the European Organi- LHC Season 2 zation for Nuclear Research, on the Franco-Swiss border facts & figures near , .

CERN's Accelerator Complex

What is the LHC? CMS explained almost all experimental results in The LHC is a accelerator that pushes particle . But the is LHC North Area incomplete. It leaves many questions open, or to near the . It 2008 (27 km)

ALICE TT20 LHCb which the LHC will help to answer. consists of a 27-kilometre ring of supercon- TT40 TT41 SPS 1976 (7 km) TI8 TI2 ducting with a number of accelerating TT10 ATLAS AWAKE HiRadMat 2016 • What is the origin of ? The Standard 2011 TT60 structures that boost the of the ELENA AD Model does not explain the origins of mass, nor TT2 2016 (31 m) 1999 (182 m) BOOSTER 1972 (157 m) why some particles are very heavy while others along the way. ISOLDE p 1989 p East Area have no mass at all. However, theorists Robert n-ToF PS 2001 H+ 1959 (628 m) Brout, François Englert and made LINAC 2 CTF3 e– Why is it called the “Large Hadron LEIR LINAC 3 a proposal that was to solve this problem. The Ions 2005 (78 m) Collider”? Brout-Englert- gives a mass

p () neutrons p– () proton/antiproton conversion to particles when they interact with an invi- • "Large" refers to its size, approximately 27km • Inside the LHC, two particle beams travel at in circumference. close to the speed of light before they are made sible field, now called the “Higgs field”, which LHC Large SPS Super Proton PS pervades the . Particles that interact • "Hadron" because it accelerates protons or ADtoAntiproton collide. Decelerator CTF3 The Clic Test FacilitybeamsAWAKE Advanced travel WAKefield Experiment in oppositeISOLDE Separator direc OnLine DEvice- LEIR LINAC LINear ACcelerator n-ToF Neutrons Time Of Flight HiRadMat High-Radiation to Materials intensely© CERN 2014 with the Higgs field are heavy, while ions, which belong to the group of particles tions in separate beam pipes – two tubes kept at ultrahigh vacuum. They are guided around those that have feeble interactions are light. In called . the accelerator ring by a strong magnetic field the late , started the search for • "Collider" because the particles form two maintained by superconducting electroma- the Higgs , the particle associated with beams travelling in opposite directions, which gnets. Below a certain characteristic tempera- the Higgs field. In July 2012, CERN announced the discovery of the , which confir- are made to collide at four points around the ture, some materials enter a superconducting state and offer no resistance to the passage med the Brout-Englert-Higgs mechanism. machine. of electrical current. The electromagnets in the However, finding it is not the end of the story, LHC are therefore chilled to -271.3°C (1.9K) and researchers have to study the Higgs boson How does the LHC work? – a colder than outer space – to in detail to measure its properties and pin down • The CERN accelerator complex is a suc- take advantage of this effect. The accelerator its rarer decays. cession of machines with increasingly higher is connected to a vast distribution system of liquid , which cools the magnets, as well • Will we discover evidence for supersym- . Each machine accelerates a beam as to other supply services. metry? The Standard Model does not offer of particles to a given energy before injecting a unified description of all the fundamental the beam into the machine in the chain. What are the main goals of the LHC? forces, as it remains difficult to construct a This next machine brings the beam to an even The Standard Model of – a theory of similar to those for the other theory developed in the early 1970s that des- forces. – a theory that hy- higher energy and so on. The LHC is the last cribes the fundamental particles and their pothesises the existence of more massive par- element of this chain, in which the beams reach interactions – has precisely predicted a wide tners of the standard particles we know – could their highest energies. variety of phenomena and so far successfully facilitate the unification of fundamental forces.

.ch • What are and ? The matter we know and that makes up all How much does the LHC cost? stars and galaxies only accounts for 4% of the • Construction costs (MCHF) content of the universe. The search is then still open for particles or phenomena responsible Personnel Materials Total for dark matter (23%) and dark energy (73%). LHC machine and areas* 1224 3756 4980

• Why is there far more matter than anti- CERN share to detectors 869 493 1362 matter in the universe? Matter and antimat- ter must have been produced in the same LHC computing (CERN share) 85 83 168 amounts at the time of the Big Bang, but from Total 2178 4332 6510 what we have observed so far, our Universe is made only of matter. *Includes: Machine R&D and injectors, tests and pre-operation

• How does the - give • Costs for Run 1 The directly allocated resources for the rise to the particles that constitute the mat- Exploitation costs of the LHC when running years 2009-2012 were about 1.1 billion CHF. ter of our Universe? For part of each year, the (direct and indirect costs) represent about LHC provides collisions between ions, • Costs for LS1 80% of the CERN annual budget for opera- recreating conditions similar to those just after The cost of the Long Shutdown 1 (22 months) tion, maintenance, technical stops, repairs and the Big Bang. When heavy ions collide at high is estimated at 150 Million CHF. energies they form for an instant the quark- consolidation work in personnel and materials The maintenance and upgrade works represent gluon plasma, a “fireball” of hot and dense (for machine, injectors, computing, experi- about 100 MCHF for the LHC and 50 MCHF for matter that can be studied by the experiments. ments). the accelerator complex without the LHC.

How was the LHC designed? Scientists started thinking about the LHC in the The CERN Data Centre stores more than 30 early 1980s, when the previous accelerator, the petabytes of data per year from the LHC expe- • 8 October 2013: Physics Nobel prize to Fran- LEP, was not yet running. In December 1994, riments, enough to fill about 1.2 million Blu-ray çois Englert and Peter Higgs for “the theoreti- CERN Council voted to approve the construc- discs, i.e. 250 years of HD video. cal discovery of a mechanism that contributes tion of the LHC and in October 1995, the LHC Over 100 petabytes of data are permanently to our understanding of the origin of mass of technical design report was published. archived, on tape. subatomic particles, and which recently was Contributions from Japan, the USA, and confirmed through the discovery of the pre- other non-Member States accelerated the pro- What is the LHC power consumption? dicted fundamental particle, by the ATLAS and cess and between 1996 and 1998, four expe- The total power consumption of the LHC (and CMS experiments at CERN’s Large Hadron riments (ALICE, ATLAS, CMS and LHCb) re- experiments) is equivalent to 600 GWh per Collider” ceived official approval and construction work year, with a maximum of 650 GWh in 2012 when the LHC was running at 4 TeV. For Run 2, What are the main goals Quantity Number the estimated power consumption is 750 GWh for the second run of the LHC? Circumference 26659 m per year. The discovery of the Higgs boson was only The total CERN energy consumption is 1.3 the first chapter of the LHC story. Indeed, Dipole operating 1.9 K (-271.3°C) TWh per year while the total electrical energy the restart of the machine this year marks the temperature production in the world is around 20000 TWh, beginning of a new adventure, as it will ope- Number of magnets 9593 in the European Union 3400 TWh, in rate at almost double the energy of its first Number of main dipoles around 500 TWh, and in Geneva canton 3 TWh. run. Thanks to the work that has been done 1232 during the Long Shutdown 1, the LHC will now What are the main achievements of be able to produce 13 TeV collisions (6.5 TeV Number of main 392 the LHC so far? per beam), which will allow physicists to further quadrupoles explore the of our Universe. Number of RF cavities 8 per beam • 10 September 2008: LHC first beam Nominal energy, protons 6.5 TeV How long will the LHC run? • 23 November 2009: LHC first collisions The LHC is planned to run over the next 20 Nominal energy, ions 2.56 TeV/u (energy per years, with several stops scheduled for up- ) • 30 November 2009: world record with beam grades and maintenance work. Nominal energy, protons energy of 1.18 TeV 13 TeV collisions No. of bunches per • 16 December 2009: world record with colli- 2808 proton beam sions at 2.36 TeV and significant quantities of No. of protons per data recorded 1.2 x 1011 bunch (at start) • March 2010: first beams at 3.5 TeV (19 Number of turns per 11245 March) and first high energy collisions at 7 TeV second (30 March) Number of collisions per 1 billion second • 8 November 2010: LHC first lead-ion beams • 22 April 2011: LHC sets new world record started on the four sites. beam intensity

Important figures: the energy of • 5 April 2012: First collisions at 8 TeV the LHC for Run 2 What are the detectors at the LHC? • 4 July 2012: Announcement of the discovery There are seven experiments installed at the of a Higgs-like particle at CERN LHC: ALICE, ATLAS, CMS, LHCb, LHCf, TO- TEM and MoEDAL. They use detectors to ana- • 28 September 2012: Tweet from CERN: "The lyse the myriad of particles produced by col- LHC has reached its target for 2012 by delive- lisions in the accelerator. These experiments ring 15 fb-1 (around a million billion collisions) are run by of scientists from to ATLAS and CMS" institutes all over the world. Each experiment is distinct, and characterized by its detectors. • 14 February 2013: At 7.24 a.m, the last beams for physics were absorbed into the What is the data flow from the LHC LHC, marking the end of Run 1 and the begin- experiments? ning of the Long Shutdown 1