Large Hadron Collider

• ATLAS
• CMS
• LHCb
• ALICE

• LHCf
• TOTEM

• MoEDAL

• Linear accelerators for protons (p ) or lead nuclei (Pb)
• Proton Synchrotron Booster (PSB )
• Proton Synchrotron (PS )
• Super Proton Synchrotron (SPS )

The Large Hadron Collider (LHC, German designation Large Hadron Collider ) is a particle accelerator at the European Organization for Nuclear Research CERN in Geneva. In terms of energy and frequency of particle collisions, the LHC is the most powerful particle accelerator in the world. At the planning and construction over 10,000 scientists and engineers from over 100 countries were involved, it cooperated with hundreds of university departments and research institutes. The key component is a synchrotron in a 26.7 km long underground ring tunnel in which protons or lead nuclei accelerated in opposite direction to nearly the speed of light are brought to collision. The experiments at the LHC are therefore Colliding -Beam Experiments.

Research goals at the LHC are the generation and accurate investigation of known and yet unknown elementary particles and states of matter. The starting point is the review of the current Standard Model of particle physics. Therefore, special attention is paid to the already long-sought Higgs boson, the last not yet experimentally verified at start- particles of the Standard Model. In addition, the LHC search for physics beyond the Standard Model is intended to be able to find answers to open questions. Four large and two smaller detectors register the traces of the resulting particles in the collisions. The large achievable number of collisions per second ( high luminosity ) creates huge amounts of data. These are sorted by a sophisticated IT infrastructure. Only a small part of the data is forwarded using a specially constructed, global computer network for analysis at the participating institutions.

The experiments in the newly developed energy sector began in late 2009 An important result of the previous experiments. (As of 2013) is a very good confirmation of the Standard Model. Several new hadrons were found, a quark -gluon plasma could be generated the first time the CP violation has been observed in the Bs0 -meson decay into kaons and pions his and his extremely rare decay into two muons. As a biggest success applies the experimental evidence of a new elementary particle, which is very likely to be the Higgs boson. This led to the award of the Nobel Prize for Physics in 2013 to François Englert and Peter Higgs.

• 3.1 Basic Research
• 3.2 The Higgs boson
• 3.3 Quark -gluon plasma
• 3.4 Clarification of Standard Model parameters
• 3.5 Physics beyond the Standard Model

History

The direct predecessor of the LHC was operated until 2000 the Large Electron - Positron Collider (LEP ). For him, in the 1980s, the ring tunnel had been built, in which the LHC is located today. The possibility of continued use of the tunnel, which had already been considered in the LEP in the design, was decisive for the choice of location of the LHC. The detailed plans for the LHC began as early as the LEP was still under construction. In LEP were electrons and positrons, which are among the leptons, brought into collision. In contrast, the LHC collide protons or atomic nuclei, which are among the hadrons. Hence the name Large Hadron Collider stirred.

In a ten -year planning and preparation phase was clarified what specific questions should be examined with the LHC and whether an accelerator -based superconductivity is even technically feasible. On 16 December 1994, the CERN Council finally gave the green light for construction. First, the energy with which the colliding protons will be 10 TeV and later increased to 14 TeV should. After India and Canada had declared non-member states of CERN, thus to contribute to the financing and development of the LHC and its subsequent use, it was decided in December 1996 to dispense with the intermediate step of 10 TeV and directly 14 TeV in attack take. Cooperation agreements with other states followed. 1997 gave the Italian Istituto Nazionale di Fisica Nucleare the first prototype of the dipole magnets, the first successful test took place in the following year. This year, the official Swiss and French authorities gave their approval to the necessary construction that were needed for the new caverns of the largest detectors. The tunnel expansion began in late 2000 and was completed in 2003. Within one good year 40,000 tons of material were removed from the tunnel.

In the years from 1998 to 2008 continuously tests were performed on individual components and subsequently subcontracted for the industrial production. In parallel, the detector systems were assembled and the connection to existing accelerators such as the SPS produced. The components came from all over the world, such as the wire chambers for the muon detector of ATLAS in more than half a dozen states have been made ​​. The brass supplied by Russia for the CMS detector comes from a treaty for defense conversion. 2006, the production of all superconducting main magnets was completed in February 2008 were the last components of the ATLAS at their destination.

The preparatory work for data processing led in 2001 to the start of the European DataGrid Project. Two years later, a new record was achieved for data transfer via the Internet. Within an hour, a data volume of one terabyte was sent from CERN to California. After two more years, the participants of the LHC Computing Grid had already grown to more than 100 centers in over 30 countries.

Official launch of the accelerator operation at the LHC was September 10, 2008, when for the first time a proton pack lapped the entire ring. But a technical defect resulted after only nine days to a one-year standstill: The weld a superconducting compound did not think the load was destroyed and a helium tank of the cooling system, the explosion in turn moved a 30 -ton magnets by half a meter. In this " quenching " went six tonnes of liquid helium lost, the concerned magnets heated rapidly to about 100 ° C. After recommissioning on 20 November 2009 found three days later in the particle, the first proton -proton collisions take place, a further six days later, the proton beam reached 1.05 TeV, the energy of the Tevatron, the most powerful particle accelerator until then. During the winter of 2009/10 improvements have been made at the particle accelerator that allowed 3.5 TeV per beam, ie, a center of mass energy of 7 TeV. On 30 March 2010 for the first time found collisions take place with this energy. All those responsible showed great satisfaction, as well as CERN Director General Rolf -Dieter Heuer:

"It's a great day to be a particle physicist. A lot of people have waited a long time for this moment, but Their patience and dedication is starting to pay dividends. "

"Today is a great day for particle physicists. Many people have waited a long time for this moment, but now starting to pay off their patience and commitment. "

The following year and a half through, interrupted only by a scheduled maintenance shutdown in winter 2010/ 11, the detectors proton -proton collisions at 7 TeV center of mass energy could investigate. The originally planned number of collisions was exceeded thanks to constantly improved beam focusing. The operation in the proton mode was interrupted on 30 October 2011 at insert until the next maintenance shutdown in winter 2011/12 with a short phase collisions of lead nuclei.

Originally, the LHC should go the end of 2011 in a longer conversion period of 15 to 18 months to replace the existing connections between the magnet and the accelerator at 7 TeV ( 14 TeV center of mass energy ) to prepare after about two years of operation. In January 2011, however, was decided before the term of the conversion phase to extend by one year until the end of 2012. Later this date was postponed to early 2013. The reason for the decision was the excellent performance of the accelerator in the first year of operation, so that signs of new particles were to be expected after a three -year term, which was confirmed with the discovery of a new elementary particle (see also The Higgs boson ).

From 5 April 2012 to December 17, 2012 proton -proton collisions were examined again. The center of mass energy was increased to 8 TeV. Then again followed by collisions of lead nuclei and additionally collisions between lead nuclei and protons.

Since the end of February 2013, the LHC is in the first longer conversion phase, which is expected to last until 2015. At this time the accelerator for its maximum energy is to be prepared.

Construction, operation and functioning

Accelerator ring

The LHC was built in the existing ring tunnel of the European Nuclear Research CERN, where the Large Electron-Positron Collider was previously installed until its closure in 2000. In addition to the tunnel two detector chambers of the LEP could continue to be used, only the chambers for the ATLAS and CMS detectors had to be rebuilt. The tunnel has a diameter of about 3.80 meters and a circumference of 26.659 kilometers and lies, with a slight inclination of 1.4% in 50 to 175 meters depth. The accelerator ring is not exactly circular, but consists of eight arcs and eight straight sections. The largest experimental facilities and the pre-accelerator located in Meyrin in French-speaking Switzerland, the control booth is located in France. Large parts of the accelerator rings and some underground experimental spaces are located on French territory.

The LHC tunnel contains two adjacent radiant tubes in which circulated two hadron beams in the opposite direction. For space reasons, both beamlines had to be housed in a common tube with magnets and cooling equipment. To allow collisions of the particles to the jets intersect at four points of the ring. On the previous model, the LEP, this still happened in eight places. In the jet pipes there is an ultra-high vacuum, so that as little as possible an accelerated particles collide with a gas molecule of the residual air. To this end, 178 turbo-molecular pumps and 780 ion getter pumps are installed along the ring. The residual pressure of the vacuum is bar at 10-14 to 10-13, which is about the measurable atmospheric pressure on the moon. The magnets and the helium supply lines are surrounded by a vacuum insulation to maintain the flow of heat to a minimum. The insulating vacuum of the magnets has a volume of about 9,000 m3.

The limiting factor for the achievable energy is the field strength of the magnets, which provide for the distraction. To have less cause sharp changes in direction, less straight sections and instead longer, weaker curved arc sections in the ring would have been better. For cost reasons, but was waived a tunnel reconstruction. The high-energy particles are kept in the LHC superconducting dipole magnets by 1232 of niobium and titanium in its orbit, which create a magnetic flux density of up to 8.33 Tesla using currents of 11,850 amperes. The strength of the magnetic field the dipoles and the frequency of the electric field in the accelerating cavities can be continuously adapted to the increasing energy of the particles. In order to keep the focused particle beams and to the collision rate to increase at the intersection of the two beams are 392 superconducting quadrupole magnets are also used. The magnets are cooled down in two steps to its operating temperature of 1.9 K ( -271.25 ° C), close to absolute zero. In the first step, they are pre-cooled with 10,080 tonnes of liquid nitrogen at 80 K ( -193.2 ° C), placed in the second step using 100 tons of liquid helium to its final temperature. In order to keep the magnets at their operating temperature, they are constantly surrounded by about 60 tonnes of liquid helium in the superfluid state. In this state, helium has a particularly good thermal conductivity. A total of 140 tons of helium for cooling purposes are stocked at the LHC. The LHC is therefore the largest cryostat, which was built until now.

During operation of the accelerator facility, the water level of Lake Geneva and other external interference, alongside the tide, change the scope of the ring by about 1 mm, are considered.

Proton mode

For the proton mode in the LHC a center of mass energy of 14 TeV was provided. This is equivalent to 99.9999991 % of the speed of light. So far 8 TeV have been achieved from 2015 to collisions with about 13 TeV be possible. To achieve such energy, the protons are accelerated one after the other by a number of systems. The protons are first brought (0.05 GeV ) in a linear accelerator to an energy of 50 MeV. They are then accelerated by the already existing before the construction of the LHC rings of the Proton Synchrotron Booster, the Proton Synchrotron and the Super Proton Synchrotron at 450 GeV (0.45 TeV ), until they are finally threaded into the main ring of the LHC, where their attain the desired energy. Accelerating the protons is based on the principle of the synchrotron by a high-frequency alternating electric field, and takes about 20 minutes.

The protons are concentrated in the beam tubes in packages. The length of these packets is a few centimeters, the diameter of about 1 mm - in the vicinity of the collision zone, the beam is compressed to a width of about 16 microns. Each package contains about 100 billion protons. When fully operational, the LHC should be filled with about 2800 packages which are rotated at a frequency of 11 kHz, ie 11,000 times per second. In normal operation, a proton pack remains up to a day in the beam tube, and places a distance of 26 billion kilometers, which corresponds to six times the distance between Earth and Neptune.

When crossing the rays penetrated in the collision zone to the current maintenance stop every 50 nanoseconds two proton bunches - later 25 nanoseconds are planned, which was tested as already achieved. During regular operation, about 20 to 40 per protons of both packages actually meet, that is then up to 800 million collisions per second. The luminosity is expected to reach 1034 cm -2s -1. The previously reached maximum luminosity is 0.76 · 1034 cm -2s -1 with 1374 packets.

Lead mode

For producing a beam of atomic nuclei of high purity lead, lead is first heated to about 550 ° C, and the resulting ionized vapor lead of an electron beam. Generated under different loading conditions, the most commonly occurring 208Pb29 ions are selected and accelerated to 4.2 MeV per nucleon. Then, a carbon film is used as the " stripping ", that is, when passing through the film lead ions losing more electrons. Most lose 25 electrons and are now as Pb54 ions. This lead ions are in the Low Energy Ion Ring ( Leir ) accelerated to 72 MeV per nucleon below the Proton Synchrotron (PS ) to 5.9 GeV per nucleon. When flying through a second stripper foil the lead nuclei lose all remaining electrons, it now is completely ionized Pb82 . Finally, these cores are in the Super Proton Synchrotron (SPS ) accelerated to 117 GeV per nucleon and fed into the LHC, which will take them to 2.76 TeV per nucleon. ( 0.2 mJ ) thus at a center of mass energy of 1148 TeV instead, which is about the energy of motion of a fly in flight - Total is the collision of lead nuclei - each with 208 nucleons.

LHC compared to LEP and Tevatron

In the Tevatron, the other main ring accelerator with counterpropagating beams, particles were current in the two beam pipes with opposite charges in the opposite direction. Following the same principle, the LHC 's predecessor LEP worked. All particles move in its orbit by a rectified magnetic field. Due to the relativistic Lorentz force they learn the required inward deflection, this keeps them on their circular path. At the LHC, however, the counter-rotating protons or lead ions carry the same charge. In the two jet pipes must therefore, the magnetic field point in opposite directions in order to deflect all particles inside. According to the concept of John Blewett (1971), this is achieved by an approximately ring-shaped magnetic field which penetrates the bottom of a jet from top to bottom and the other upwards.

While were placed in the LEP electrons and positrons, so the anti-particle collide with each other, are at the LHC accelerates depending on the operating mode protons or lead nuclei and brought into collision. Due to the much larger mass of the hadrons they lose less energy through synchrotron radiation and can reach a far greater energy. The higher compared to the previous experiments focus energy enables the exploration of new energy ranges. By choosing protons instead of antiprotons in the second beam such as at the Tevatron, a higher luminosity could be achieved beyond. The high particle density at the points of interaction leads to the desired, high event rates in the particle and makes it possible to collect large amounts of data in less time.

Security measures

The total energy in each of the two counterpropagating beams in the proton mode in the order of 300 megajoules. This corresponds to the kinetic energy of a vehicle is running at 150 km / h ICE. This energy is sufficient to melt about half a ton of copper, in the event of an uncontrolled " beam loss " the accelerator facility would be severely damaged. The project manager of the LHC in 1994, Lyn Evans, speaks of an amount of energy, as contained in 80 kg of TNT. The system is so designed that within three rounds (ie less than 300 millionths of a second ) an unstable jet expectant registered and is discharged through special magnets in a special branch of the tunnel. There is a particular beam stopper, which is constructed from a number of graphite sheets of different densities, and can intercept the beam. The energy stored in the dipole magnet is 11 GJ much higher, the current through the magnet coils is collected if necessary switched in via resistors. The damage in the accident, which occurred in 2008 at the start of the accelerator operation (see story), stemmed from the energy stored in the magnets.

Both the particle on its curved path as well as the inevitable collisions produce radiation. The stay in the tunnel or the caverns of the detectors is not possible during the beam times. Maintenance work must be accompanied by active and passive radiation protection measures. The ground above the tunnel keeps the scattered radiation during operation, and the residual radioactivity back effect. The air from the accelerator tunnel is filtered with the aim to keep the radioactivity released for the residents always below the value of 10 mSv per year.

Since it is possible in some models beyond the Standard Model that may microscopic black holes or strange matter could be produced at the LHC, there is anecdotal warnings that the LHC could destroy the Earth. A group led by biochemist Otto Rossler turned to the European Court of Human Rights filed a complaint against the commissioning of the LHC. The urgent application related was dismissed in August 2008 by the court. The German Federal Constitutional Court refused to accept a constitutional complaint in February 2010 due to lack of fundamental importance and lack of prospects of success. Skilled scientists found repeatedly that the LHC and other particle accelerators has no risk. Supporting arguments here are, firstly, that the theoretically possible, microscopic black holes would immediately annihilate rather than as feared absorb more and more mass or energy from the environment, and secondly, that natural cosmic radiation constantly with even higher energy than the LHC on the Earth's atmosphere and meets other celestial bodies, without causing disasters.

Detectors

The collision of protons by crossing the two proton beams in four underground chambers along the accelerator ring. In the chambers are the four large particle detectors ATLAS, CMS, LHCb and ALICE. The TOTEM detectors and LHCf are much smaller and are located in the chambers of the CMS or ATLAS experiment. They examine only particles that roam each other in the collisions rather than collide. In addition, more specific experiments are planned with associated detector units, such as MoEDAL to search for magnetic monopoles and relics of microscopic black holes and supersymmetric particles.

The thrust of the four large detector systems can be simplified summarized as follows:

The complex internal structure of the protons causes the event of collisions often arise many particles. This leads to high demands on the detector systems to detect as completely as possible those particles and their properties. Since the resulting particles are very diverse in their properties, various detector components are needed, which are specifically adapted for particular problems. The only exception to the resulting neutrinos that can not be detected directly. It is the determination of the place of origin of the respective collision products is crucial: it must not coincide with the point of collision of protons, as a part of the short-lived products even disintegrates during flight through the detector.

The basic structure of the detectors consists of a sequence of different parts detectors of different design and operating principles that the collision point as completely surrounded by the onion skin principle. Strong magnetic fields of superconducting magnets ensure a deflection of the charged particles. From the path curvature, specific charge and momentum of charged particles can be determined. The innermost layer is called the tracking detector, a semiconductor detector with fine spatial resolution. It is surrounded by an electromagnetic calorimeter and a hadronic and a spectrometer for muons.

The lead cores are mainly located in the ALICE detector for collision, which was built specifically for the measurement of these collisions. To a lesser extent, ATLAS and CMS investigate such heavy-ion collisions. In addition, lead- cores can be brought into collision with protons, which is being investigated by the four large detectors.

Data Analysis

The amount of data that accumulates as a result recorded detector signals or computer simulations in operation is estimated at 15 million gigabytes per year. The amount of data would be substantially greater if not elaborate trigger verwürfen on the hardware and software level, a large part of the measuring signals prior to processing or long-term storage. Only the amount of data of the CMS detector is comparable to that of a 70 - megapixel camera, which makes 40 million frames per second. Without trigger such data sets would not be manageable with current technology. So the 40 million beam crossings per second about 75,000 are in the ATLAS detector in the first trigger stage of the data selected. Of these happen less than 1000, the second trigger level, and only these events are fully analyzed. In the end, about 200 events per second stored permanently.

To process this reduced amount of data computing power required is still large enough for about 150 globally distributed computer clusters are used. These are connected to a computer network, the LHC Computing Grid. For the simulation of particle trajectories home computer owners are involved in the project LHC @ that provide the computing power for their private computer available according to the principle of distributed computing.

Power supply

Haupteinspeisepunkt for the supply of the CERN electrical energy is the 400 - kV substation Prevessin, which is connected via a short branch line to the 400 kV substation Bois- Toillot in conjunction. Another power is supplied at 130 kV in the station Meyrin. Of these entry points lead 66 -kV and 18 - kV underground to the larger Umspannpunkten where a lashing is at the operating voltage of the terminals ( 18 kV, 3.3 kV and 400 V). In the event of a power outage emergency generators with an output of 275 kVA and 750 kVA installed in the experimental stations, especially for sensitive equipment an uninterruptible power supply is guaranteed.

The storage ring requires an electrical output of 120 MW. Together with the cooling system and the experiments resulting in a power consumption of about 170 MW. Because of the higher cost of electricity, the LHC will shut down in the winter part, thereby reducing the power required then reduced to 35 MW. The maximum annual energy consumption of the LHC is given as 700-800 GWh. By comparison, the nearly 10% of consumption of the Canton of Geneva. In this case, the energy consumption by the use of the LHC superconducting magnets is smaller than in the previous experiments, such as the LEP.

Costs

The direct cost for the LHC project, without the detectors amounts to about 3 billion euros. With the approval of the construction in 1995 with a budget of 2.6 billion Swiss francs (then according to 1.6 billion euro) for the construction of the LHC and the underground halls for the detectors. However, additional costs of 480 million Swiss francs ( 300 million euros ) in 2001 were estimated for the accelerator, which alone accounted for 180 million Swiss francs ( 120 million euros ) on the superconducting magnets. Other cost increases incurred due to technical difficulties in the construction of the underground hall for the Compact Muon Solenoid, partly due to defective parts that had been provided by the partner laboratories Argonne National Laboratory, Fermilab and KEK available.

Research objectives and results to date

Basic research

The scientists hope to gain from the experiments at the LHC answering fundamental questions about the basic forces of nature, the structure of space and time as well as the relationship between quantum physics and relativity. The experiments at the LHC will either confirm the Standard Model of elementary particle physics or show that corrections to the physical picture of the world are needed.

The high collision energy of the LHC has the consequence that not the proton as a whole, but whose individual constituents, quarks and gluons collide independently. In most cases, is involved in the impact of each of the two protons, respectively, or a single curd gluon. Although the energy of the protons before the collision has a precisely defined value, but can the energy and momentum of individual quarks or gluons according to the parton distribution functions vary over a wide range, so that the collision energy of the two actually relevant collision partners can not be precisely defined. Because of this, it is both possible to search in spite of constant energy of the protons in a wide energy range by newly generated particles, which is why the LHC is referred to as a "discovery machine". On the other hand, the possibility is limited to measure certain properties of these new particles precisely. For this reason, it is already thinking about a successor to the LHC. The International Linear Collider will then, as at other times already in the LEP, again electrons and positrons are made ​​to collide. Their energy can be precisely adjusted and unlike protons they have not - at least not known - substructure.

The Higgs boson

One of the main tasks of the LHC is the search for the Higgs boson, the last not yet been definitively proven particles of the Standard Model of particle physics. On 4 July 2012, the research groups reported on the detectors ATLAS and CMS that they have a new boson found. Whether this is described by the Standard Model Higgs boson, has yet to be clarified by measuring its properties. The Higgs boson would confirm theories by which the masses of elementary particles can be introduced into the standard model or in the Glashow -Weinberg -Salam theory of the electroweak interaction. In other words, the Higgs boson confirmed the existence of the so-called Higgs field and the underlying Higgs mechanism; this field is omnipresent in the universe and through interaction with the elementary particles their mass.

For the in 1964 published related theory François Englert and Peter Higgs was awarded the 2013 Nobel Prize in Physics.

Quark -gluon plasma

The rare compared to proton collisions Applied operating mode of the collision of lead nuclei serves to briefly produce a very high energy plasma of quasi-free quarks and gluons, called a quark-gluon plasma. At the ALICE detector, the conditions are this way modeled and studied, who have ruled according to the Big Bang model shortly after the Big Bang.

Clarification of Standard Model parameters

Compared to previous accelerators LHC has a higher energy and a higher data rate. Thus, it is suitable to determine the properties of an elementary proven the standard model in more detail than in previous experiments was possible. So could the previous experiment Tevatron the heaviest of the known elementary particles, the top quark, although demonstrated its properties are determined but only very inaccurate because of the small number of produced particles and the resulting poor statistics. At the LHC, however, top quarks are produced in large numbers, allowing a more accurate study of the properties of this particle. He is the first so-called " t- factory". In addition, several new hadrons were found at the LHC, for example, the χb (3P ) - meson.

Another important research area is the matter-antimatter asymmetry in the universe that is not explained by the standard Big Bang theory. Under asymmetry, the fact is understood that the visible universe is composed solely of matter and not equal parts of matter and antimatter. The study of B physics, with a focus on the LHCb experiment, will help the CKM matrix to measure accurately. This matrix contains a CP violating component, which is an important building block for the explanation of the matter-antimatter asymmetry. However, the size of the predicted by the Standard Model CP violation can not explain the observed asymmetry, so that the measurements are also used for deviations from the standard model to search. The LHCb collaboration could prove CP violation in B - mesons for the first time.

The tests of the Standard Model also includes the study of the rare decay of Bs0 - meson into two muons, which was first observed at the LHC. The prediction that decay of about three billion Bs0 mesons in exactly this way, it was confirmed in the LHCb detector and then by CMS. Without this decay, such a measurement result otherwise only with a probability of less than 0.001 % would be possible.

Physics beyond the Standard Model

On the review of the standard model and the accurate measurement of its parameters at the LHC is also intensely for clues for physics beyond the Standard Model (English Physics beyond the Standard Model) sought. By far the biggest expense is operated for the discovery of evidence of supersymmetry. Since the supersymmetric extension of the standard model is very complex, mainly certain supersymmetric models will be tested at the LHC, such as the minimal supersymmetric standard model ( MSSM ). Many of the tested models are based on the results of the LHC experiments already ruled out. Some of these models emerging new particles, such as the lightest supersymmetric particle, represent a possible particle physics explanation for the postulated in astrophysics dark matter dar. Furthermore, supersymmetry part of most models, which combine the three interactions of the standard model - the so-called grand unified theories. In addition, it is necessary for the superstring theory. In professional circles it is believed that many super affiliates have a mass in the range from about 100 GeV to 1 TeV and thus can be generated and measured principally at the LHC. A typical signal for supersymmetry would be to produce electrically neutral super affiliates. These possible particle dark matter can not be registered by the detector directly, make, however, in the reconstruction of the entire collision process via special decay signatures with high missing momentum noticeable.

Another object of research in physics beyond the standard model are due to their small size yet undiscovered dimensions of space. These extra dimensions could make itself felt through increased interaction with gravitons, by the detection of Kaluza-Klein particles or by the generation of short-lived microscopic black holes.

Future

The term of the LHC is expected to 2030Vorlage: / end future in 5 years. Until that time, however, there are a variety of plans. Since February 2013, the first conversion phase, which is to last until 2015. After that, the proton energy is expected to reach 6.5 TeV, and to enable the luminosity reach their design value.

For 2018Vorlage: Future / In 4 years, a longer conversion period of about 18 months is planned to increase the luminosity further. These new quadrupoles are used in order to better focus the particle beam. The prototypes are already in construction. Another concept, through special cavities, so-called Crab cavities to rotate the elongated bunches just before the interaction point so that they collide as centrally as possible and thus penetrate better. In addition, the inner detectors of ALICE, CMS and LHCb be replaced in order to obtain a higher resolution.

Further improvements are planned for the distant future. Which of these will be implemented, will depend, among other things, of the discoveries already made. A concept provides for the conversion of the LHC before to even higher energies ( High Energy LHC). This would require the field strength of all the dipole magnets of 8.3 Tesla current increased to 20 Tesla and need new quadrupoles are used, whereby energy of 16.5 TeV ( center of mass energy 33 TeV ) could be achieved. However, including the luminosity would suffer because only half as many bunches could be accelerated. Another concept is to further increases in luminosity without increasing the energy. To the number of circulating particles, and its focus can be increased further. Also, a conversion to a Hadron Electron Collider would be possible ( LHeC ).