From:http://www.newscientist.com
Protons have made their first complete lap of the world’s most powerful accelerator to cheers and high fives from assembled physicists.
At 1025 (local time) scientists sent a single beam of protons in a clockwise direction around the full 27 kilometres of the Large Hadron Collider at the CERN laboratory near Geneva, Switzerland.
The journey began at 0930 when LHC project leader Lyn Evans and his team launched protons into the ring. Progress was made in short steps of a few kilometres, so that physicists could learn how to steer the beam, which is travelling at 99.9998% the speed of light.
Steering particles
The LHC's tunnel is filled with devices called collimators, which steer the beam every few kilometres. Evans and his team opened the collimators one by one when they were sure that they could steer the protons precisely.
The machine worked better than anyone expected. It took only 55 minutes for physicists to steer beams around the full 27km, and the LHC worked on its first go, far better than anyone dared to hope.
Earlier Evans said that he did not know how long it would take his team to circulate the beam.
"It took us 12 hours to circulate a beam around the Large Electron Positron Collider," says Evans. The LEP Collider was the LHC's predecessor that was shut down in 2000.
Giant freezer
Physicists working on two of the giant experiments – CMS and ATLAS – have seen sprays of particles in their detectors as protons smashing into the collimators next to the detectors (see image, top right).
The day was not without its dramas, however. During the night, part of the cryogenic system that keeps the ring chilled to 1.9 kelvin (just above absolute zero) failed.
The ring has to be cold for the powerful magnets to work. Physicists managed to fix the problem overnight and started the day's tests on schedule.
Evans hopes initially to circulate the beams many times in the clockwise direction. The team will attempt to repeat the test later today, but sending protons around in the opposite direction.
However, it will be several weeks before physicists accelerate two proton beams travelling in opposite directions to their full energy of 7 teraelectronvolts, and smash them head on.
The Large Hadron Collider – Find out more about the world's biggest experiment in our cutting-edge special report.
Sunday 14 September 2008
'Big Bang' experiment starts well
By Paul Rincon Science reporter, BBC News
Scientists have hailed a successful switch-on for an enormous experiment which will recreate the conditions a few moments after the Big Bang.
They have now fired two beams of particles called protons around the 27km-long tunnel which houses the Large Hadron Collider (LHC).
The £5bn machine on the Swiss-French border is designed to smash protons together with cataclysmic force.
Scientists hope it will shed light on fundamental questions in physics.
The first - clockwise - beam completed its first circuit of the underground tunnel at just before 0930 BST. The second - anti-clockwise - beam successfully circled the ring after 1400 BST.
We will be looking at what the Universe was made of billionths of a second after the Big Bang
Dr Tara Shears, University of Liverpool
What is the Large Hadron Collider?So far, all the beams have been stopped, or "dumped", after just a few circuits.
On Thursday, engineers hoped to inject clockwise and anti-clockwise protons again, but this time they plan to "close the orbit", letting the beams run continuously for a few seconds each.
The BBC understands that low-energy collisions could happen in the next few days. This will allow engineers to calibrate instruments, but will not produce data of scientific interest.
"There it is," project leader Lyn Evans said when the beam completed its lap. There were cheers in the control room when engineers heard of the successful test.
They have now fired two beams of particles called protons around the 27km-long tunnel which houses the Large Hadron Collider (LHC).
The £5bn machine on the Swiss-French border is designed to smash protons together with cataclysmic force.
Scientists hope it will shed light on fundamental questions in physics.
The first - clockwise - beam completed its first circuit of the underground tunnel at just before 0930 BST. The second - anti-clockwise - beam successfully circled the ring after 1400 BST.
We will be looking at what the Universe was made of billionths of a second after the Big Bang
Dr Tara Shears, University of Liverpool
What is the Large Hadron Collider?So far, all the beams have been stopped, or "dumped", after just a few circuits.
On Thursday, engineers hoped to inject clockwise and anti-clockwise protons again, but this time they plan to "close the orbit", letting the beams run continuously for a few seconds each.
The BBC understands that low-energy collisions could happen in the next few days. This will allow engineers to calibrate instruments, but will not produce data of scientific interest.
"There it is," project leader Lyn Evans said when the beam completed its lap. There were cheers in the control room when engineers heard of the successful test.
He added later: "We had a very smooth start-up."
The LHC is arguably the most complicated and ambitious experiment ever built; the project has been hit by cost overruns, equipment trouble and construction problems. The switch-on itself is two years late.
The collider is operated by the European Organization for Nuclear Research - better known by its French acronym Cern.
The vast circular tunnel - or "ring" - which runs under the French-Swiss border contains more than 1,000 cylindrical magnets arranged end-to-end.
The magnets are there to steer the beam around this vast circuit.
Big Bang DayEventually, two proton beams will be steered in opposite directions around the LHC at close to the speed of light, completing about 11,000 laps each second.
At allotted points around the tunnel, the beams will cross paths, smashing together near four massive "detectors" that monitor the collisions for interesting events.
Scientists are hoping that new sub-atomic particles will emerge, revealing fundamental insights into the nature of the cosmos.
Major effort
"We will be able to see deeper into matter than ever before," said Dr Tara Shears, a particle physicist at the University of Liverpool.
"We will be looking at what the Universe was made of billionths of a second after the Big Bang. That is amazing, that really is fantastic."
The LHC should answer one very simple question: What is mass?
LHC DETECTORS
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
CMS - the second general purpose detector will, like ATLAS, hunt for the Higgs boson and look for clues to the nature of dark matter
ALICE - will study a "liquid" form of matter called quark-gluon plasma that existed shortly after the Big Bang
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
"We know the answer will be found at the LHC," said Jim Virdee, a particle physicist at Imperial College London.
The favoured model involves a particle called the Higgs boson - dubbed the "God Particle". According to the theory, particles acquire their mass through interactions with an all-pervading field carried by the Higgs.
The latest astronomical observations suggest ordinary matter - such as the galaxies, gas, stars and planets - makes up just 4% of the Universe.
The rest is dark matter (23%) and dark energy (73%). Physicists think the LHC could provide clues about the nature of this mysterious "stuff".
But Professor Virdee told BBC News: "Nature can surprise us... we have to be ready to detect anything it throws at us."
Full beam ahead
Engineers injected the first low-intensity proton beams into the LHC in August. But they did not go all the way around the ring.
Technicians had to be on the lookout for potential problems.
Steve Myers, head of the accelerator and beam department, said: "There are on the order of 2,000 magnetic circuits in the machine. This means there are 2,000 power supplies which generate the current which flows in the coils of the magnets."
If there was a fault with any of these, he said, it would have stopped the beams. They were also wary of obstacles in the beam pipe which could prevent the protons from completing their first circuit.
Superconducting magnets are cooled down using liquid helium
Mr Myers has experience of the latter problem. While working on the LHC's predecessor, a machine called the Large-Electron Positron Collider, engineers found two beer bottles wedged into the beam pipe - a deliberate, one-off act of sabotage.
The culprits - who were drinking a particular brand that advertising once claimed would "refresh the parts other beers cannot reach" - were never found.
In order to get both beams to circulate continuously, engineers will "close the orbit". The beams themselves are made up of several "packets" - each about a metre long - containing billions of protons.
The protons would disperse if left to their own devices, so engineers use electrical forces to "grab" them, keeping the particles tightly huddled in packets.
Once the beams are captured, the same system of electrical forces is used to give the particles an energetic kick, accelerating them to greater and greater speeds.
Long haul
The idea of the Large Hadron Collider emerged in the early 1980s. The project was eventually approved in 1996 at a cost of 2.6bn Swiss Francs, which amounts to about £1.3bn at present exchange rates.
However, Cern underestimated equipment and engineering costs when it set out its original budget, plunging the lab into a cash crisis.
FROM THE TODAY PROGRAMME
More from Today programme
Cern had to borrow hundreds of millions of euros in bank loans to get the LHC completed. The current price is nearly four times that originally envisaged.
During winter, the LHC will be shut down, allowing equipment to be fine-tuned for collisions at full energy.
"What's so exciting is that we haven't had a large new facility starting up for years," explained Dr Shears.
"Our experiments are so huge, so complex and so expensive that they don't come along very often. When they do, we get all the physics out of them that we can."
Engineers celebrated the success with champagne, but a certain brand of beer was not on the menu.
Paul.Rincon-INTERNET@bbc.co.uk
The LHC is arguably the most complicated and ambitious experiment ever built; the project has been hit by cost overruns, equipment trouble and construction problems. The switch-on itself is two years late.
The collider is operated by the European Organization for Nuclear Research - better known by its French acronym Cern.
The vast circular tunnel - or "ring" - which runs under the French-Swiss border contains more than 1,000 cylindrical magnets arranged end-to-end.
The magnets are there to steer the beam around this vast circuit.
Big Bang DayEventually, two proton beams will be steered in opposite directions around the LHC at close to the speed of light, completing about 11,000 laps each second.
At allotted points around the tunnel, the beams will cross paths, smashing together near four massive "detectors" that monitor the collisions for interesting events.
Scientists are hoping that new sub-atomic particles will emerge, revealing fundamental insights into the nature of the cosmos.
Major effort
"We will be able to see deeper into matter than ever before," said Dr Tara Shears, a particle physicist at the University of Liverpool.
"We will be looking at what the Universe was made of billionths of a second after the Big Bang. That is amazing, that really is fantastic."
The LHC should answer one very simple question: What is mass?
LHC DETECTORS
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
CMS - the second general purpose detector will, like ATLAS, hunt for the Higgs boson and look for clues to the nature of dark matter
ALICE - will study a "liquid" form of matter called quark-gluon plasma that existed shortly after the Big Bang
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
"We know the answer will be found at the LHC," said Jim Virdee, a particle physicist at Imperial College London.
The favoured model involves a particle called the Higgs boson - dubbed the "God Particle". According to the theory, particles acquire their mass through interactions with an all-pervading field carried by the Higgs.
The latest astronomical observations suggest ordinary matter - such as the galaxies, gas, stars and planets - makes up just 4% of the Universe.
The rest is dark matter (23%) and dark energy (73%). Physicists think the LHC could provide clues about the nature of this mysterious "stuff".
But Professor Virdee told BBC News: "Nature can surprise us... we have to be ready to detect anything it throws at us."
Full beam ahead
Engineers injected the first low-intensity proton beams into the LHC in August. But they did not go all the way around the ring.
Technicians had to be on the lookout for potential problems.
Steve Myers, head of the accelerator and beam department, said: "There are on the order of 2,000 magnetic circuits in the machine. This means there are 2,000 power supplies which generate the current which flows in the coils of the magnets."
If there was a fault with any of these, he said, it would have stopped the beams. They were also wary of obstacles in the beam pipe which could prevent the protons from completing their first circuit.
Superconducting magnets are cooled down using liquid helium
Mr Myers has experience of the latter problem. While working on the LHC's predecessor, a machine called the Large-Electron Positron Collider, engineers found two beer bottles wedged into the beam pipe - a deliberate, one-off act of sabotage.
The culprits - who were drinking a particular brand that advertising once claimed would "refresh the parts other beers cannot reach" - were never found.
In order to get both beams to circulate continuously, engineers will "close the orbit". The beams themselves are made up of several "packets" - each about a metre long - containing billions of protons.
The protons would disperse if left to their own devices, so engineers use electrical forces to "grab" them, keeping the particles tightly huddled in packets.
Once the beams are captured, the same system of electrical forces is used to give the particles an energetic kick, accelerating them to greater and greater speeds.
Long haul
The idea of the Large Hadron Collider emerged in the early 1980s. The project was eventually approved in 1996 at a cost of 2.6bn Swiss Francs, which amounts to about £1.3bn at present exchange rates.
However, Cern underestimated equipment and engineering costs when it set out its original budget, plunging the lab into a cash crisis.
FROM THE TODAY PROGRAMME
More from Today programme
Cern had to borrow hundreds of millions of euros in bank loans to get the LHC completed. The current price is nearly four times that originally envisaged.
During winter, the LHC will be shut down, allowing equipment to be fine-tuned for collisions at full energy.
"What's so exciting is that we haven't had a large new facility starting up for years," explained Dr Shears.
"Our experiments are so huge, so complex and so expensive that they don't come along very often. When they do, we get all the physics out of them that we can."
Engineers celebrated the success with champagne, but a certain brand of beer was not on the menu.
Paul.Rincon-INTERNET@bbc.co.uk
Wednesday 10 September 2008
Safety issues
Safety of particle collisions
Main article: Safety of the Large Hadron Collider
Although some individuals, including scientists, have questioned the safety of the planned experiments in the media and through the courts, the consensus in the scientific community is that there is no basis for any conceivable threat from the LHC particle collisions.[25][26][27]
Operational safety
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.[6][28] While operating, the total energy stored in the magnets is 10 GJ (equivalent to 2.4 tons of TNT) and the total energy carried by the two beams reaches 724 MJ.[29]
Loss of only one ten-millionth part (10−7) of the beam is sufficient to quench a superconducting magnet, while the beam dump must absorb an energy equivalent to that of a typical air-dropped bomb. These immense energies are even more impressive considering how little matter is carrying it: under nominal operating conditions (2,808 bunches per beam, 1.15×1011 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, a technician was killed in the LHC tunnel when a crane load was accidentally dropped.[30] 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.[31] 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.[32][33] Repairing the broken magnet and reinforcing the eight identical assemblies used by LHC delayed the startup date,[34] then planned for November 2007, by several weeks.
In popular culture
The Large Hadron Collider has been featured in a number of novels, including Flashforward by Robert J. Sawyer, Black Hole by Angelo Paratico,[35] and Decipher by Stel Pavlou, which described it in some detail. One of the most visible examples is 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.[36] The movie version of the book has footage filmed on-site at one of the experiments at the LHC; the director, Ron Howard, also met with CERN experts in an effort to make the science in the story more accurate.[37] CERN employee Katherine McAlpine's "Large Hadron Rap"[38] surpassed two million YouTube views on 10 September 2008.[39][40][41]
BBC Radio 4 broadcast "Big Bang Day" on 10 September 2008 to coincide with the LHC being switched on. Included in this event was a radio episode of the TV series Torchwood, with a plot involving the LHC, entitled Lost Souls.[42][43]
On 10 September, to commemorate the firing of the Large Hadron Collider, Google displayed a custom Google Doodle[44] with a drawing of the LHC which linked to a web search for "Large Hadron Collider". It is a tradition for Google to change their logo to represent what they consider to be important or interesting events.[citation needed]
A 16-year-old girl from Sarangpur, Madhya Pradesh, India allegedly committed suicide after watching Indian news channels stating the possibility of Doomsday as the experiment begins.[45]
Main article: Safety of the Large Hadron Collider
Although some individuals, including scientists, have questioned the safety of the planned experiments in the media and through the courts, the consensus in the scientific community is that there is no basis for any conceivable threat from the LHC particle collisions.[25][26][27]
Operational safety
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.[6][28] While operating, the total energy stored in the magnets is 10 GJ (equivalent to 2.4 tons of TNT) and the total energy carried by the two beams reaches 724 MJ.[29]
Loss of only one ten-millionth part (10−7) of the beam is sufficient to quench a superconducting magnet, while the beam dump must absorb an energy equivalent to that of a typical air-dropped bomb. These immense energies are even more impressive considering how little matter is carrying it: under nominal operating conditions (2,808 bunches per beam, 1.15×1011 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, a technician was killed in the LHC tunnel when a crane load was accidentally dropped.[30] 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.[31] 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.[32][33] Repairing the broken magnet and reinforcing the eight identical assemblies used by LHC delayed the startup date,[34] then planned for November 2007, by several weeks.
In popular culture
The Large Hadron Collider has been featured in a number of novels, including Flashforward by Robert J. Sawyer, Black Hole by Angelo Paratico,[35] and Decipher by Stel Pavlou, which described it in some detail. One of the most visible examples is 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.[36] The movie version of the book has footage filmed on-site at one of the experiments at the LHC; the director, Ron Howard, also met with CERN experts in an effort to make the science in the story more accurate.[37] CERN employee Katherine McAlpine's "Large Hadron Rap"[38] surpassed two million YouTube views on 10 September 2008.[39][40][41]
BBC Radio 4 broadcast "Big Bang Day" on 10 September 2008 to coincide with the LHC being switched on. Included in this event was a radio episode of the TV series Torchwood, with a plot involving the LHC, entitled Lost Souls.[42][43]
On 10 September, to commemorate the firing of the Large Hadron Collider, Google displayed a custom Google Doodle[44] with a drawing of the LHC which linked to a web search for "Large Hadron Collider". It is a tradition for Google to change their logo to represent what they consider to be important or interesting events.[citation needed]
A 16-year-old girl from Sarangpur, Madhya Pradesh, India allegedly committed suicide after watching Indian news channels stating the possibility of Doomsday as the experiment begins.[45]
Proposed upgrade
Proposed upgrade
CMS detector for LHC
Main article: Super Large Hadron Collider
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 LHC, has been proposed,[21] 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 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.
Cost
The total cost of the project is anticipated to be €3.2–6.4 billion.[1] The construction of LHC was approved in 1995 with a budget of 2.6 billion Swiss francs (€1.6 billion), with another 210 million francs (€140 million) towards the cost of the experiments. However, cost over-runs, estimated in a major review in 2001 at around 480 million francs (€300 million) for the accelerator, and 50 million francs (€30 million) for the experiments, along with a reduction in CERN's budget, pushed the completion date from 2005 to April 2007.[22] The superconducting magnets were responsible for 180 million francs (€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 faulty parts loaned to CERN by fellow laboratories Argonne National Laboratory and Fermilab.[23]
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.[24]
Computing resources
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.
The distributed computing project LHC@home was started to support the construction and calibration of the LHC. The project uses the BOINC platform 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.
CMS detector for LHC
Main article: Super Large Hadron Collider
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 LHC, has been proposed,[21] 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 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.
Cost
The total cost of the project is anticipated to be €3.2–6.4 billion.[1] The construction of LHC was approved in 1995 with a budget of 2.6 billion Swiss francs (€1.6 billion), with another 210 million francs (€140 million) towards the cost of the experiments. However, cost over-runs, estimated in a major review in 2001 at around 480 million francs (€300 million) for the accelerator, and 50 million francs (€30 million) for the experiments, along with a reduction in CERN's budget, pushed the completion date from 2005 to April 2007.[22] The superconducting magnets were responsible for 180 million francs (€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 faulty parts loaned to CERN by fellow laboratories Argonne National Laboratory and Fermilab.[23]
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.[24]
Computing resources
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.
The distributed computing project LHC@home was started to support the construction and calibration of the LHC. The project uses the BOINC platform 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.
Test timeline
Test timeline
September 2008
The first beam was circulated through the collider on the morning of 10 September 2008.[17] 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 am local time.[18] 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.[19] CERN next successfully sent a beam of protons in a counterclockwise direction.
October 2008
The first high-energy collisions are planned to take place after the LHC is officially unveiled on 21 October 2008
September 2008
The first beam was circulated through the collider on the morning of 10 September 2008.[17] 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 am local time.[18] 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.[19] CERN next successfully sent a beam of protons in a counterclockwise direction.
October 2008
The first high-energy collisions are planned to take place after the LHC is officially unveiled on 21 October 2008
Research
Research
When in operation, about seven thousand scientists from eighty countries will have access to the LHC. Physicists hope to use the collider to test various grand unified theories and enhance their ability to answer the following questions:
Is the popular Higgs mechanism for generating elementary particle masses in the Standard Model realised in nature? If so, how many Higgs bosons are there, and what are their masses?[14]
Will the more precise measurements of the masses of the quarks continue to be mutually consistent within the Standard Model?
Do particles have supersymmetric ("SUSY") partners?[1]
Why are there apparent violations of the symmetry between matter and antimatter?[1] See also CP-violation.
Are there extra dimensions, as predicted by various models inspired by string theory, and can we "see" them?
What is the nature of dark matter and dark energy?[1]
Why is gravity so many orders of magnitude weaker than the other three fundamental forces?
Renowned British astrophysicist Stephen Hawking has bet against the mega-experiment finding the elusive Higgs particle. "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 $100 that we won't find the Higgs," Hawking speculated, but the experiment could discover superpartners, particles that would be supersymmetric partners to particles already known. "Their existence would be a key confirmation of string theory, and they could make up the mysterious dark matter that holds galaxies together. Whatever the LHC finds, or fails to find, the results will tell us a lot about the structure of the universe," he said.[15]
As an ion collider
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 programme. While lighter ions are considered as well, the baseline scheme deals with lead ions.[16] This will allow an advancement in the experimental programme currently in progress at the Relativistic Heavy Ion Collider (RHIC).
When in operation, about seven thousand scientists from eighty countries will have access to the LHC. Physicists hope to use the collider to test various grand unified theories and enhance their ability to answer the following questions:
Is the popular Higgs mechanism for generating elementary particle masses in the Standard Model realised in nature? If so, how many Higgs bosons are there, and what are their masses?[14]
Will the more precise measurements of the masses of the quarks continue to be mutually consistent within the Standard Model?
Do particles have supersymmetric ("SUSY") partners?[1]
Why are there apparent violations of the symmetry between matter and antimatter?[1] See also CP-violation.
Are there extra dimensions, as predicted by various models inspired by string theory, and can we "see" them?
What is the nature of dark matter and dark energy?[1]
Why is gravity so many orders of magnitude weaker than the other three fundamental forces?
Renowned British astrophysicist Stephen Hawking has bet against the mega-experiment finding the elusive Higgs particle. "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 $100 that we won't find the Higgs," Hawking speculated, but the experiment could discover superpartners, particles that would be supersymmetric partners to particles already known. "Their existence would be a key confirmation of string theory, and they could make up the mysterious dark matter that holds galaxies together. Whatever the LHC finds, or fails to find, the results will tell us a lot about the structure of the universe," he said.[15]
As an ion collider
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 programme. While lighter ions are considered as well, the baseline scheme deals with lead ions.[16] This will allow an advancement in the experimental programme currently in progress at the Relativistic Heavy Ion Collider (RHIC).
Purpose
From Wikipedia, the free encyclopedia
When activated, it is theorized that the collider will produce the elusive Higgs boson. The verification of the existence of the Higgs boson would be a significant step in the search for a Grand Unified Theory, which seeks to unify three of the four known fundamental forces: electromagnetism, the strong nuclear force and the weak nuclear force, leaving out only gravity. The Higgs boson may also help to explain why gravitation is so weak compared with the other three forces. In addition to the Higgs boson, other theorized particles, models and states might be produced, and for some searches are planned, including supersymmetric particles,[8] compositeness (technicolor),[9] extra dimensions,[10] strangelets,[11] micro black holes and magnetic monopoles.
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