Large Hadron Collider Week – Day 1

The Large Hadron Collider

Our understanding of the Universe is about to change…

The Large Hadron Collider (LHC) is a gigantic scientific instrument near Geneva, where it spans the border between Switzerland and France about 100 m underground. It is a particle accelerator used by physicists to study the smallest known particles – the fundamental building blocks of all things. It will revolutionise our understanding, from the miniscule world deep within atoms to the vastness of the Universe.

Two beams of subatomic particles called ‘hadrons’ – either protons or lead ions – will travel in opposite directions inside the circular accelerator, gaining energy with every lap. Physicists will use the LHC to recreate the conditions just after the Big Bang, by colliding the two beams head-on at very high energy. Teams of physicists from around the world will analyse the particles created in the collisions using special detectors in a number of experiments dedicated to the LHC.

There are many theories as to what will result from these collisions, but what’s for sure is that a brave new world of physics will emerge from the new accelerator, as knowledge in particle physics goes on to describe the workings of the Universe. For decades, the Standard Model of particle physics has served physicists well as a means of understanding the fundamental laws of Nature, but it does not tell the whole story. Only experimental data using the higher energies reached by the LHC can push knowledge forward, challenging those who seek confirmation of established knowledge, and those who dare to dream beyond the paradigm.

From the LHC website. (http://public.web.cern.ch/public/en/LHC/LHC-en.html)

Another brief explanation:

The Large Hadron Collider is currently being installed in a 27-kilometer ring buried deep below the countryside on the outskirts of Geneva, Switzerland. When its operation begins in 2007, the LHC will be the world’s most powerful particle accelerator. High-energy protons in two counter-rotating beams will be smashed together in a search for signatures of supersymmetry, dark matter and the origins of mass.

The beams are made up of bunches containing billions of protons. Traveling at a whisker below the speed of light they will be injected, accelerated, and kept circulating for hours, guided by thousands of powerful superconducting magnets.

For most of the ring, the beams travel in two separate vacuum pipes, but at four points they collide in the hearts of the main experiments, known by their acronyms: ALICE, ATLAS, CMS, and LHCb. The experiments’ detectors will watch carefully as the energy of colliding protons transforms fleetingly into a plethora of exotic particles.

The detectors could see up to 600 million collision events per second, with the experiments scouring the data for signs of extremely rare events such as the creation of the much-sought Higgs boson.

From Symmetry magazine’s website. (http://www.symmetrymagazine.org/cms/?pid=1000095)

Today’s math:

These particles will be traveling at a hair less than the speed of light. It is difficult to put in perspective just how fast that really is. According to wikipedia, that speed is exactly 299,792,458 meters per second. We know from the above articles that the LHC is 27 km in circumference.

My questions are: How many laps will these particles make in one second? How can we put this in perspective?

We know that 27 km is 27,000 meters, so we simply need to divide the speed by the distance now that we have matched the units.

299,792,458 divided by 27,000.

I will spare you the long division and let you know the answer is in the range of 11,103.42 laps PER SECOND! When compared to the Indianapolis Motor Speedway at 2.5 miles per lap and an average race time of 3 hours, you realize just how fast these particles are moving. If you are looking at the collider when the particles are up to speed and blink, you will miss between 3300 and 4400 laps depending on how fast you blink. Imagine blinking during the Indy 500. You would not miss much.

The math and science behind the LHC, CERN, and the Grid that CERN utilizes are exciting and interesting and we will be looking at them this entire week. Thanks to Symmetry and the LHC website for the information used. Please take a look at them so you can be part of the excitement this summer when the projects run. Check back tomorrow where we will explore the tremendous amount of data that these experiments will generate.