Large Hadron Collider
 

The Large Hadron Collider (LHC) is a particle accelerator of the European Organization for Nuclear Research (CERN) that lies under the Franco-Swiss border near Geneva, Switzerland. The LHC is in the final stages of construction and commissioning, with some sections already being cooled down to their final operating temperature of approximately 2K. The first beams are due for injection mid June 2008 with the first collisions planned to take place 2 months later. The LHC will become the world's largest and highest-energy particle accelerator. The LHC is being funded and built in collaboration with over two thousand physicists from thirty-four countries as well as hundreds of universities and laboratories.

When activated, it is theorized that the collider will produce the elusive Higgs boson, the observation of which could confirm the predictions and "missing links" in the Standard Model of physics and could explain how other elementary particles acquire properties such as mass. 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 to the other three forces. In addition to the Higgs boson, other theorized novel particles that might be produced, and for which searches are planned, include strangelets, micro black holes, magnetic monopoles and supersymmetric particles.

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 underground. The tunnel, constructed between 1983 and 1988, was formerly used to house the LEP, an electron-positron collider.

The 3.8 metre diameter, concrete-lined tunnel crosses the border between Switzerland and France at four points, although most of its length is inside France. The collider itself is underground, with surface buildings holding ancillary equipment such as compressors, ventilation equipment, control electronics and refrigeration plants.

The collider tunnel contains two pipes, each pipe containing a beam. The two beams travel in opposite directions around the ring. 1232 dipole magnets keep the beams on their circular path, while 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 will cross. In total, over 1600 superconducting magnets are installed, with most weighing over 27 tonnes. 96 tonnes of liquid helium is needed to keep the magnets at the operating temperature.

The protons will each have an energy of 7 TeV, giving a total collision energy of 14 TeV. It will take less than 90 microseconds for an individual proton to travel once around the collider. Rather than continuous beams, the protons will be "bunched" together, into 2,808 bunches, so that interactions between the two beams will take place at discrete intervals never shorter than 25 ns apart. When the collider is first commissioned, it will be operated with fewer bunches, to give a bunch crossing interval of 75 ns. The number of bunches will later be increased to give a final bunch crossing interval of 25 ns.

Prior to being injected into the main accelerator, the particles are prepared through a series of systems that successively increase the particle energy levels. The first system is the linear accelerator Linac 2 generating 50 MeV protons which feeds the Proton Synchrotron Booster (PSB). Protons are then injected at 1.4 GeV into the Proton Synchrotron (PS) at 26 GeV. Finally the Super Proton Synchrotron (SPS) is used to increase the energy of protons up to 450 GeV.

The LHC will also be used to collide lead (Pb) heavy ions with a collision energy of 1,150 TeV. The ions will be first accelerated by the linear accelerator Linac 3, and the Low-Energy Injector Ring (LEIR) will be used as an ion storage and cooler unit. The ions then will be further accelerated by the Proton Synchrotron (PS) and Super Proton Synchrotron (SPS) before being injected into LHC ring, where they will reach an energy of 2.76 TeV per nucleon. Six detectors are being constructed at the LHC, located underground in large caverns excavated at the LHC's intersection points. Two of them, ATLAS and CMS, are large, "general purpose" particle detectors.

ALICE is a large detector designed to study the properties of quark-gluon plasma looking at the debris of heavy ion collisions. The other three (LHCb, TOTEM, and LHCf) are relatively smaller and more specialized. A seventh experiment, FP420 (Forward Physics at 420m), has been proposed which would add detectors to four available spaces located 420m on either side of the ATLAS and CMS detectors.

The size of the LHC constitutes an exceptional engineering challenge with unique safety issues. While running, the total energy stored in the magnets is 10 GJ, while each of the two beams carries an overall energy of 362 MJ. For comparison, 362 MJ is the kinetic energy of a TGV running at 157 km/h (98 mph), while 724 MJ, the total energy of the two beams, is equivalent to the detonation energy of approximately 173 kilograms (380 lb) of TNT, and 10 GJ is about 2.4 tons of TNT. Loss of only 10-7 of the beam is sufficient to quench a superconducting magnet, while the beam dump must absorb an energy equivalent to a typical air-dropped bomb.

These immense kinetic energies become far more spectacular when you consider how little matter is carrying it. At its maximum energy rating (2.76TeV per particle with a total of 362MJ), there is just 1.15E-9 grams of hydrogen in the system (or 0.026 of one cubic millimeter).

When in operation, about seven thousand scientists from eighty countries will have access to the LHC, the largest national contingent of seven hundred being from the United States. 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?
• 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?
• Why are there apparent violations of the symmetry between matter and antimatter?
• Are there extra dimensions indicated by theoretical gravitons, as predicted by various models inspired by string theory, and can we "see" them?
• What is the nature of dark matter and dark energy?
• Why is gravity so many orders of magnitude weaker than the other three fundamental forces?

A simulated event in the CMS detector,

featuring the appearance of the Higgs boson.

Proton-Proton Collisions at the LHC

Computer reconstruction of particle tracks, originating
from the simulated decay of a Higgs boson.

LHC 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 (Pb) ions. This will allow an advancement in the experimental programme currently in progress at the Relativistic Heavy Ion Collider (RHIC).

Proposed Upgrade

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, 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.

Although the Standard Model of particle physics predicts that LHC energies are far too low to create black holes, some extensions of the Standard Model posit the existence of extra spatial dimensions, in which it would be possible to create micro black holes at the LHC at a rate on the order of one per second. According to the standard calculations these are harmless because they would quickly decay by Hawking radiation. The concern is that among other disputed factors, Hawking radiation (the existence of which is still debated) is not yet an experimentally-tested or naturally observed phenomenon.

The opponents to the LHC consider that micro black holes produced in a terrestrial laboratory might not decay as rapidly as calculated, or might even not be prone to decay. According to CERN, physicists in general do not question the assumption that black holes are generally unstable and those few who have pointed out issues with Steven Hawking's radiation were only attempting to achieve a more rigorous proof of it.[30] "No-one ever claimed that his proof of the decay is wrong, and that therefore they should be stable." CERN further argues that even if micro black holes were created and were stable, they would pose no reasonable threat to the Earth during its remaining 5 billion years of existence. However, Dr. Adam D. Helfer's thesis concludes "no compelling theoretical case for or against radiation by black holes", and Dr. Otto E. Rossler's thesis calculates that Earth accretion time could be as short as 50 months.

A strangelet or "strange nugget" is a hypothetical object consisting of a bound state of roughly equal numbers of up, down, and strange quarks. The size could be anything from a few femtometers across (with the mass of a light nucleus) to something much larger. Once the size becomes macroscopic (on the order of meters across), such an object is usually called a quark star or "strange star" rather than a strangelet. An equivalent description is that a strangelet is a small fragment of strange matter. The term "strangelet" originates with E. Farhi and R. Jaffe. Strangelets have been suggested as a dark matter candidate.

Large Hadron Collider Wikipedia

   Large Hadron Collider YouTube -- Watch Michio Kaku

Large Hadron Collider Google Images

LHC - Large Hadron Collider CERN

Large Hadron Collider Website

Large Hadron Collider Enables Hunt For 'God' Particle To Complete 'Theory Of Everything' Science Daily - June 1, 2008
When the world's most powerful subatomic particle collider begins gathering data this summer ... Hopefully it will help unlock some deep scientific mysteries and perhaps even lead to discovery of the Higgs boson, sometimes called "the God particle" because it is believed its discovery will refine the understanding of exactly how the universe came to be and how it functions, and how mass came to be in the first place.

LHC: Amazing Images National Geographic - March 2008

The God Particle - Higgs Boson National Geographic - March 2008

Could the Large Hadron Collider destroy Earth?

By Chris Gaylord | 07.01.08

Now that the European Large Hadron Collider (LHC) is completed and ready to fire up in August, a slew of articles have popped up quoting doomsayers. An AP article from this weekend was the most recent example of critics warning that the 17-mile, $5.8 billion supercollider – which will slam protons together in an attempt to learn more about the building blocks of the universe – will inadvertently create a black hole that will gobble up the Earth.

So, will the most ambitious science project in human history end human history? No.

I should say “no, according to scientists working on the LHC.” But the evidence points to a resounding “no.”

A study released last month disassembled the arguments against powering up the collider. The report found “no basis for concerns that [small] black holes from the LHC could pose a risk to Earth on timescales shorter than the Earth’s natural lifetime.” In other words: Yes, it could happen, but chances are the sun will burn out before this collider can have an Earth-ending mishap.

Their reasoning? Slashdot puts it best: “Everything that will be created at the LHC is already being created by cosmic rays. If a black hole created by the LHC is interactive enough to destroy the world within the lifetime of the sun, similar black holes are already being created by cosmic rays.”

If such black holes were naturally flinging around in the universe, they would bump up against “dense cosmic objects,” such as neutron stars, and over time the black holes would swallow the star. But, from looking through telescopes we know that there are plenty of old neutron stars around. So, if it’s safe for them, it’s also safe for us. “Any black hole that could be created at the LHC, even if it is stable, would have no effect on the earth on any meaningful timescale,” Slashdot says.

This conclusion is backed by the European agency that runs the LHC, a panel of independent scientists, the US Department of Energy, the US National Science Foundation, and science star Stephen Hawking – who argues that even if black holes developed, “they would instantly evaporate.”

That’s good enough for me.

---

U.S. contributes to Large Hadron Collider

WASHINGTON, July 2 , 2008  (UPI) -- The U.S. Department of Energy says its contribution to the Large Hadron Collider under construction in Switzerland has been completed.

The Energy Department and the National Science Foundation said the U.S. contribution -- $531 million in several key components, including two particle detectors -- was completed on budget and ahead of schedule.

"The success of the U.S. LHC project is based on the quality of the U.S. teams, and national and international collaboration," Energy Department Undersecretary for Science Raymond Orbach said. "The U.S. groups, from universities and national laboratories, worked extraordinarily well together. We celebrate their accomplishments and, together with them, look forward to extremely exciting science coming from the LHC."

Scientists predict that the LHC's very-high-energy proton collisions will yield extraordinary discoveries about the nature of the physical universe.

The LHC is expected to generate its first particle collisions later this year. When the LHC begins scientific operations, U.S. physicists will make up the largest group of scientists from any single nation, officials said.

---

The Truth About Microscopic Black Holes and the Utter Destruction of Earth

Science fiction is rife with tales of experiments that run out of control and blow up the planet or exterminate all life or something. Maybe that's why two U.S. researchers sued the European Organization for Nuclear Research (CERN), trying to get an injunction that would prevent them from building their Large Hadron Collider. Their reason? Concern that it would create an apocalyptic mini-black hole here on Earth. Many debated whether their fears were pure cranksterism or held a grain of truth. Now a physics professor has researched the issue and discovered the truth about the LHC's inherent risks to all humanity.

The Large Hadron Collider, once operational, will fire beams of protons into each other at energy levels never seen on Earth. We don't really know what will happen when experiments begin (or we wouldn't bother running the experiments), and there are fears that all kinds of weird, hypothetical particles could be created that will devour the planet, or that a small but stable black hole will begin consuming all nearby matter. Steve Giddings, Professor of Physics at UC Santa Barbara, studied the risks. His conclusions:

• The chances of a microscopic black hole forming are impossibly small.
• Cosmic rays smash into particles all the time at very high energies. We probably would have noticed if the universe was being chewed up by an endless torrent of ravenous mini black holes.
• In the incredibly unlikely event that a microscopic black hole forms, it would exist for "a nano-nano-nanosecond." Not long enough to do any damage, in other words.
• Giddings even studied what would happen if a long chain if bizarre events occurred, and a stable micro black hole formed. The result would be...nothing much. Even a stable microscopic black hole would be harmless.

---

Earth 'not at risk' from collider

By Paul Rincon Science reporter, BBC News June 23, 2008 Our planet is not at risk from the world's most powerful particle physics experiment, a report has concluded. The document addresses fears that the Large Hadron Collider is so energetic, it could have unforeseen consequences. Critics are worried that mini-black holes made at the soon-to-open facility on the French-Swiss border might threaten the Earth's very existence. But the report, issued the European Organization for Nuclear Research, says there is "no conceivable danger". The organization - known better by its French acronym, Cern - will operate the collider underground in a 27km-long tunnel near Geneva. This Large Hadron Collider (LHC) is a powerful and complicated machine, which will smash together protons at super-fast speeds in a bid to unlock the secrets of the Universe. Six "detectors" - individual experiments - will count, trace and analyse the particles that emerge from the collisions. Most physicists believe the risk of a cataclysm lies in the realms of science fiction. But there have been fears about the possibility of a mini-black hole - produced in the collider - swelling so that it gobbles up the Earth. Critics have previously raised concerns that the production of weird hypothetical particles called strangelets in the LHC could trigger the mass conversion of nuclei in ordinary atoms into more strange matter - transforming the Earth into a hot, dead lump. New particles The lay language summary of the report, which has been written by Cern's top theorists, states: "Over the past billions of years, nature has already generated on Earth as many collisions as about a million LHC experiments - and the planet still exists." The report added: "There is no basis for any concerns about the consequences of new particles or forms of matter that could possibly be produced by the LHC." The new document is an update of the analysis carried out in 2003 into the safety of the collider by an independent team of scientists. The authors of the latest report, including theoretical physicist John Ellis, confirmed that black holes could be made by the collider. But they said: "If microscopic black holes were to be singly produced by colliding the quarks and gluons inside protons, they would also be able to decay into the same types of particles that produced them." The report added: "The expected lifetime [of a mini-black hole] would be very short." On the strangelet issue, the report says that these particles are even less likely to be produced at the LHC than in the lower-energy Relativistic Heavy Ion Collider (RHIC) in New York, which has been operating since 2000. A previous battle over particle accelerator safety was fought over the US machine. 'Fundamental question' The scientific consensus appears to be on the side of Cern's theorists. But in 2003, Dr Adrian Kent, a theoretical physicist at the University of Cambridge, wrote a paper in which he argued that scientists had not adequately calculated the risks of a "killer strangelet" catastrophe scenario. He also expressed concern that a fundamental question (how improbable does a cataclysm have to be to warrant proceeding with an experiment?) had never been seriously inspected. The LHC was due to switch on in 26 November 2007. The start-up has been postponed several times, however, and is currently scheduled for later this summer. The first delay was precipitated by an accident in March 2007 during stress testing of one of the LHC's "quadrupole" magnets. A statement carried on the Cern website from the US laboratory that provided the magnet stated that the equipment had experienced a "failure" when supporting structures "broke". It later emerged that the magnet had exploded in the tunnel, close to one of the LHC's most important detectors. No one was in the immediate vicinity of the test, so there were no injuries. The magnet problem was fixed shortly afterwards. In March, a complaint requesting an injunction against the LHC's switch-on was filed before the United States District Court for the District of Hawaii by seven plaintiffs. One of the plaintiffs had previously attempted to bring a similar injunction against the RHIC over safety concerns. Paul.Rincon-INTERNET@bbc.co.uk A Career In Microbiology Can Be Harmful To Your Health The newest connections to DynCorp, Hadron and PROMIS software are leads an ...... Hadron describes itself as “a company specializing in the development of ... www.greatdreams.com/microbiologists.htm Photons 1980, The Inner Structure of the Proton, describing photons, their breakdown into quarks, hadron jets, matter and antimatter opposites and as stated in the ... www.greatdreams.com/grace/1/1photons.html The Invisible Universe Objects made up of quarks are known as hadrons; well known examples are protons ... Further on, Jerry Iuliano comments that the top quark (hadron) is the ... www.greatdreams.com/grace/126/143invisibleuni.html MORE ABOUT THE HADRON COLLIDER AT CERN DREAMS OF THE GREAT EARTHCHANGES - MAIN INDEX