Scientists turn on biggest ‘Big Bang Machine’

ALICE: The big bang in the machine
ATLAS and CMS get most of the attention, but the contraption that best merits the title of "Big Bang Machine" is about a mile (1.5 kilometers) down the road from ATLAS. The ALICE detector (A Large Ion Collider Experiment) is designed exclusively to study the stuff that the universe was made of less than a millionth of a second after the big bang.

ALICE will run for only about a month out of every year, conducting experiments that will require the collider to switch over from smashing protons to smashing lead ions, which are 100 times heavier than protons. The high-energy collisions should blast those ions so thoroughly that, for just an instant, they turn into a plasma of free-flying quarks plus gluons, the particles that usually bind quarks together.

Past experiments indicated that the quark-gluon plasma behaved like a liquid. When ALICE gets up and running, "then maybe we reach the gas phase," said Jurgen Schukraft, CERN's spokesperson for the ALICE experiment. That would be something never before seen in the cosmic scheme of things.

LHCb: The mystery of antimatter
The fourth detector is also designed to answer a specific cosmic question. LHCb will study particles containing particular "flavors" of quarks and antiquarks, known as B mesons and anti-B mesons, with the aim of figuring out why matter has a huge edge over antimatter in our universe.

Earlier studies revealed that the particles and antiparticles decayed differently, which runs counter to the idea that matter and antimatter should be in symmetry. LHCb will follow up on those studies, using a battery of high-tech detectors that are lined up on one side of the collision point. Among those instruments are a tracker that can locate particles with a precision of 10 microns, or a tenth the width of a human hair.

Two smaller experiments round out the ring: LHCf, which studies cosmic-ray-like events near ATLAS; and TOTEM, which measures the effective size of protons using a detector near CMS.

The Grid: Getting out the data
The LHC is designed to produce as many as 600 proton collisions per second, and that creates a flood of digital data that gushes out from the detectors' wiring. If you were to put all the data from one of the main detectors onto CDs, the stack of disks would pile up to the orbit of the moon in six months. The challenge is to pick out only the most promising readings.

Each of the detectors uses "triggers" to pick out the good stuff. Only about 100 events per second are sent to thousands of computers and tape drives at CERN for storage. It's like narrowing down that moon-high stack of CDs to a stack that's only 6 miles high — which is still high enough for a transcontinental jet to run into.

To get the data out to researchers around the world, CERN has set up a multi-tier computer network called the Grid. Digital information goes out to the "Tier 1" data centers on a fiber-optic network at a rate of up to 10 gigabits per second — or roughly 1,000 times the speed of a typical cable Internet connection.

If the system works, it could set the model for future computing — not only for physics but also for other high-end applications such as climate simulation, genetic analysis and petroleum prospecting. Just as the World Wide Web was the best-known spin-off from CERN's LEP experiment back in the 1990s, the Grid could well become the LHC's most visible legacy.

Magnet for innovation
Who will benefit the most from that legacy? The Grid may distribute the data across the world — but it's hard to argue with the idea that Europe's 21st-century wonder of the world will serve as a magnet for innovation over the next decade.

That has sparked more than a few cases of "collider envy" among American researchers, and some worry about the prospects of a reverse brain drain. Michio Kaku, a theoretical physicist at the City College of New York, is already noticing a trend in his colleagues' travel plans.

"They're going where the action is, and that is Europe," Kaku said.

Chapter 4: Europe pulls ahead in scientific race

MORE FROM LHC

LHC Section Front

Big bang machine sets smashing new record Super-smasher targets massive mystery Discovery or doom? Collider stirs debate Biggest ‘Big Bang Machine’ switched on Europe leaps ahead on physics frontier A dozen totally fictional doomsdays Big-bang brouhaha sets off big reaction Learn more about the LHC on the Web Atom smashers on TV Interactive: Inside the Big Bang Machine LHC Section Front   Add LHC headlines to your news reader: