Wednesday, February 24, 2010

The Large Hadron Collider will restart soon at 7 TeV

The Large Hadron Collider, otherwise known as the LHC, is designed to hurl protons and nuclei of atoms together a phenomenally high speeds extremely close to the speed of light.

The LHC has 2 beams going in opposite directions around an oval of about 27 kilometres, at specified pints, where experiments like ATLAS and CMS are located, they cross and collisions may occur.

These collisions are at an energy high enough that particles are created from the interaction of the colliding protons and neutrons. Most of the particles detected from these collisions are known, but physicists are still interested in how they behave at the energies achieved in the LHC, but the most sought after prize is the Higgs Boson - along with possibility of finding other particles predicted, but not yet observed.

Theoretical nuclear physicists can not account for why the sub atomic particles, that we have already detected so far, have mass. So Peter Higgs, along with others, postulated a totally new type of particle, now called the Higgs Boson, that appears to neatly resolve the problem.

Some other physicists, think that the Higgs Boson does not exist, and there must be some other mechanism to account for mass. However, most physicists feel that searching for the Higgs is worthwhile, as it is important to find evidence of it either definitely existing or not existing, as the case may be. The existence of the Higgs would confirm our understanding of the so called standard model of nuclear particles and allow our understanding of it to be extended to higher energies, or force physicists to reconsider the standard model in a very fundamental way.

Also of considerable interest: would be new types of particles not predicted, and new ways of matter behaving at the super high temperatures found in the collisions of nuclear particles at the LHC.

The LHC had been designed to run at 10 TeV (10,000,000,000,000 electron volts, as distinct from the maximum energy possible in the average New Zealand home of 240 volts), but due to technical problems they will run at 7 TeV. The LHC will be run at this energy for 18 to 24 months to get a decent amount of physics done and to get more experience of operating the system, plus it gives more time to prepare what is required to operate at the design energy of 10 TeV.

Note that the LHC is run at about 270 degrees Celsius below the freezing point of water, or less than 2 degrees above absolute zero. So another reason for the long period at just one energy level of 7 TeV, is that while there are improvements they can make to increase the energy in stages to 10 TeV, is that simply warming the LHC up to room temperature and cooling it down again takes at least 2 months, in addition to the time required to make the actual engineering modifications and subsequent testing.

It is expected that the LHC will restart operations in the few days about the level it finished last year of about 1 TeV and ramp up over a few week to 7 TeV. They want to avoid any mishaps that might put the LHC out of commission, like what happened shortly after they started up the first time when they had an explosion that forced a delay of a year while they fixed the problem.

Physicists from all around the world are hard at work preparing to do some exciting new physics at the LHC, including some people from New Zealand.

Thursday, February 4, 2010

White Blood Cell Chases Bacteria

Here is an excellent video, and at the end it gives a chance to look at more videos that give further glimpses into what is happening at the microscopic level of life.

Tuesday, February 2, 2010

Age no barrier to being productive in Theoretical Physics

Edward & Nappi are 2 Theoretical Physicists married to each other, talking about where advances are most likely to be made in their field (part 2 of 2 of the article). Note that Ed's wife is confident that they can both still contribute effectively, despite being 50+.
He reckons the most influential insights in string theory will come from the younger generation, but Nappi isn't so sure. She cites a recent study showing that scientists in their 50s and 60s are at least as productive as those in their 30s, if not more so. "We are planning to get a lot more work done now that the children have moved out," she says. It's a fearsome prospect: Ed Witten might just be entering his prime.
Be sure to also look at part 1 of the article, Inside the tangled world of string theory!