Friday, January 9, 2009

The Fractal Wonders of Cern—Searching for the Elusive Higgs Boson: The God Particle

This artistically-enhanced image of particle tracks was produced in the Big European Bubble Chamber (BEBC) at CERN, the European Organization for Nuclear Physics—the world’s largest particle physics laboratory, built in 1954 in the northwest suburbs of Geneva on the Franco-Swiss border. Liquid hydrogen creates bubbles along the paths of the particles as a piston expands the medium. A magnetic field produced in the detector causes the particles to travel in spirals, allowing charge and momentum to be measured.

The BEBC was installed at CERN in the early 1970s to study particle physics. CERN's main function is to provide the particle accelerators and other infrastructure needed for high-energy physics research. CERN operates a network of six accelerators and a decelerator. Each machine in the chain increases the energy of particle beams before delivering them to experiments or to the next more powerful accelerator.

The Large Hadron Collider (LHC) is the world’s largest and most powerful particle accelerator and the latest addition to CERN’s accelerator complex. Physicists are using the LHC to study the smallest known particles, and hoping to revolutionize our understanding of the universe. They are doing this by creating the conditions just after the Big Bang through the collision of two beams head-on at extremely high energy then monitoring the debris to learn more about how our universe started and works.

The LHC lies about 175 m underground in a tunnel large enough to run a train through. It is essentially a 27 km ring of superconducting magnets with a number of accelerating structures to boost the energy of the particles along the way. With construction overseen by over 10,000 scientists and engineers from over 100 countries, the LHC was built to test various predictions of high-energy physics, including the existence of Higgs boson (a massive scalar particle predicted to exist by the Standard Model) sometimes called "the God particle" because some believe its discovery will help us understand exactly how the universe came to be, how it functions, and how mass came to be in the first place.

Two beams of subatomic particles called 'hadrons' – either protons or lead ions – travel in opposite directions inside the circular accelerator, gaining energy with every lap. Physicists are using the LHC to recreate the conditions just after the Big Bang, by colliding the two beams head-on at very near the speed-of-light. Teams of physicists from around the world analyze the particles created in the collisions using special detectors in highly specialized experiments. Atlas, with its over 90,000 tubes, is one of six particle physics experiments (CMS, ATLAS, LHCb, TOTEM, LHC-forward and ALICE) of the Large Hadron Collider. The Atlas subsystem detects subatomic particles called muons, which have little interaction with each other or with other matter and are formed as a byproduct of the collisions between protons, the nuclei of hydrogen atoms. Someone even wrote a very cool rap about it.

Discussion in the news and on the Internet, generally, surrounding the September 10 2008 start up of the Large Hadron Collider bordered on hysteria and hyperbole. Blogs and forums exploded with wild hypotheses and arguments about the end of the universe or at least our planet as we know it. Fear that the LHC would create a black hole or a series of black holes that would destroy the entire planet and gobble up the galaxy ran rampant.

The hysteria even spawned a lawsuit against CERN by a group of Hawaiians who were afraid that the LHC would either eat the Earth with a black hole, or just render it a mass of inert matter via a hypothetical “strangelet.” One particularly snarky rebuttal to this charge can be found here.

Last March, two American environmentalists filed a lawsuit in Federal District Court in Honolulu seeking to force the U.S. government to withdraw its participation in the experiment. The lawsuits have in turn spawned several websites, chat rooms and petitions. On a less serious note, I particularly enjoyed this series of discussion that ended up discussing the inevitable disaster movie

Anyway, all this led to alarming headlines around the world (Britain's Sun newspaper on Sept. 1: "End of the World Due in 9 Days"). According to Hawking, if tiny black holes occurred at CERN, they would evaporate before they got a chance to do any damage. Speaking of Hawking, he was hoping to end his losing streak of science-related bets with his wager of $100 (E70) that CERN’s Large Hadron Collider wouldn’t find the Higgs boson. “I think it will be much more exciting if we don’t find the Higgs,” he said. “That will show something is wrong, and we need to think again. I have a bet of 100 dollars that we won’t find the Higgs.”

Hawking told the BBC that “whatever the LHC finds, or fails to find, the results will tell us a lot about the structure of the universe.” The LHC could instead find certain physical structures that would be “a key confirmation of string theory, and they could make up the mysterious dark matter that holds galaxies together.”

"We don’t even know what to expect," said French physicist Yves Schutz prior to the first experimental test of the LHC. "We’re now in a domain of energy that nobody has ever explored." Others called the LHC “possibly the world’s first time machine.”

Then, at 10:28 on September 10, 2008, the first beam of protons circulated in the LHC, marking a key moment in over two decades of preparation and putting to rest the doomsayers. "It’s a fantastic moment," said the LHC project leader Lyn Evans, "we can now look forward to a new era of understanding about the origins and evolution of the universe".

The hunt for the “God Particle” is on! The Large Hadron Collider may also lead to a better understanding of the fourth fundamental force -- gravity -- in terms of particle interactions, and may help solve the puzzle of why gravity is the weakest of the fundamental forces.

According to some sources, temperatures generated are more than 1,000,000 times hotter than the sun’s core and superconducting magnets are cooled to a temperature colder than in deep space. Shortly after the September start-up, a large helium leak into a sector of the Hadron Collider tunnel, likely from a faulty electrical connection between two of the accelerator’s magnets, compelled CERN to investigate. The LHC will be started up again in spring of this year following the winter shutdown for the maintenance of all the CERN installations. To find out the latest at CERN go here.

This track is an example of simulated data modeled for the CMS detector on the Large Hadron Collider (LHC) at CERN, which began taking data in 2008. The Higgs boson is produced in the collision of two protons at 14 TeV and quickly decays into four muons, a type of heavy electron which is not absorbed by the detector. The tracks of the other products of the collision are shown by lines and the energy deposited in the detector is shown in blue.

This is an image from an ATLAS collision event in which a microscopic-black-hole was produced in the collision of two protons. It is one of the first images from CMS, showing the debris of particles picked up in the detector's calorimeters and muon chambers after the beam was steered into the collimator (tungsten block).

The streamer chamber: pion decay -- The real particles produced in the decay of a positive pion can be seen in this image from a streamer chamber. Streamer chambers consist of a gas chamber through which a strong pulsed electric field is passed, creating sparks as a charged particle passes through it. A magnetic field is added to cause the decay products to follow curved paths so that their charge and momentum can be measured.

UA1: z particle decay -- A colour treated picture of the computer reconstruction of the real particle tracks emerging from a high energy proton-antiproton collision recorded in the UA1 detector at the SPS (converted to act as a collider). This picture shows the production of a Z particle that has decayed into a high energy electron and positron flying off in opposite directions (in yellow). The UA1 detector ran on the SPS accelerator at CERN between 1981 and 1993.

You can find more images of CERN here.

Here’s a bit of incredible trivia for you: did you know that The World Wide Web began as a CERN project called ENQUIRE, initiated by Sir Tim Berners-Lee and Robert Cailliau in 1989? Cool, eh?


Carlos said...

Hi! Care to x-link? I have added you already in my list. Have a nice day!

blackburn1 said...
This comment has been removed by the author.
blackburn1 said...

I have to admit when the event happened, and was followed shortly afterward by the critical failure, there was a small voice going 'ha ha' inside my head. I don't wish the scientists to fail- their proposition is fascinating- but somehow it seems fitting that the audacity of calling anything a "God Particle" should become appropriately elusive.

So when is your next appearance? Please don't say this weekend, I'm going out of town! I seem to recall a date closer to the end of the month... hoping. =]

SF Girl said...

Hey, thanks, Carlos! I will certainly drop by your site. Thanks for the link.

Blackburn... you're right... there is one at the end of the month, but it's a workshop. You can check the details on the booktour widget on my right sidebar. Its on January 29th, I think and it's at the Ladner Pioneer Library. You're very welcome to register (it's free, I think). Otherwise, I will be doing a few signings in February at various Chapters in town... :) See you at one of those! :D

Keyword said...

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blackburn1 said...

Chapters. Which means Starbucks. Ah... this is becoming an event. Okay, shaping up. Thanks. =]

SF Girl said...

LOL! It certainly is! Looking forward to it, Blackburn... And I have something for you when we do meet... :D

Jean-Luc Picard said...

There was a lot of publicity about the Collider. The media seemed to think something BIG was going to happen when switched on.

SF Girl said...

Yes... and then, soon after the Big Guy broke...

Hydrogen Helium Leak Testing said...

Nobody knows the exact working principle and conditions of this experiment then why everyone is wildly guessing about the outcomes.

SF Girl said...

Human nature, I guess... :)

Anonymous said...

Just needed to point out that I bet few of the scientists like to call the higgs-boson a God particle (arrogant indeed). This has to be a nickname invented by the press. And people; patience, patience, science is possible only with rigour and patience (the Higgs boson is found, by now)