Tales of the big bang
Posted: Tuesday, March 10, 2009 7:41 PM by Alan Boyle
JHU Press |
"The Quantum Frontier" focuses
on the Large Hadron Collider.
|
Scientists at the Large Hadron Collider have barely begun their quest to unlock the smallest mysteries of the universe - but there's already a book that explains the whole story, written by a researcher who's still deeply involved in the plot.
"The Quantum Frontier," by Fermilab physicist Don Lincoln, delves into the workings of the LHC as well as the basic (and not-so-basic) outlines of the scientific frontier the $10 billion machine was built to explore.
Far beneath the French-Swiss border, the LHC had its official startup last September - and soon afterward it suffered some serious glitches that required months of repair. The latest word is that the collider won't start up again until this coming September at the earliest. Once it's back in operation, scientists could discover how it is that some particles (like protons) have mass while others (like photons) don't. They could learn the nature of dark matter, or confirm that our universe has extra dimensions, or find whole classes of weird new subatomic particles.
Or they could discover something completely different.
"It's completely wrong-minded to say that 'the LHC was built to discover X,'" Lincoln writes. "That would mean that 'X' is understood well enough to know that it's there, and therefore to find it isn't really a discovery. No, the purpose of the LHC is to study the nature of matter under conditions that are seven times hotter and more energetic than ever before observed. We will see what we will see."
Fortunately, Lincoln doesn't stop there: He goes on to explain the ABCs of particle physics as well as the XYZs of scientific mysteries. One of Lincoln's favorite mysteries is the subject of his own research, which focuses on what he calls "the next layer of the onion."
If matter is made of molecules, and molecules are made of atoms, and atoms are made of particles like electrons and protons, and protons are made of quarks ... then what are quarks made of? No one really knows, although theorists have talked about the existence of pre-quarks or "preons." (Plenty of other names have been proposed for the theoretical particles; Lincoln's favorites are "quinks" and "tweedles").
In an interview, Lincoln noted that physicists now know enough about the various flavors of quarks (up, down, bottom, top, strange and charmed) to organize them into a periodic table of sorts. "That's telling me something," he said. "My guess is that this is evidence of something inside quarks."
The LHC could point to the things inside quarks if high-energy collisions produce characteristic sprays and jets of particles, Lincoln said. "You would expect to see more scatters than you would if in fact quarks had no size," he told me.
Another big mystery has to do with the origins of particle mass. For decades, scientists have suggested that a factor known as the Higgs field affects some particles to give them mass, while not affecting others. Lincoln describes the field as an "add-on" that modifies the way particles behave - just as air resistance is an add-on that determines why a lead ball falls faster than a feather through Earth's atmosphere.
Detecting the particle that's associated with the Higgs field - known as the Higgs boson or the "God Particle" - is one of modern physics' top quests. Lincoln happens to be part of two research groups involved in the search: the DZero collaboration at Fermilab and the Compact Muon Solenoid collaboration at the LHC.
For the past couple of years, scientists have wondered whether the first evidence of the Higgs boson would be found at Fermilab or the LHC. "It's not a race per se," Lincoln said, but the folks at Fermilab would love to make the discovery before handing off the baton to their colleagues at Europe's CERN particle physics lab.
Although there's no breakthrough to report yet, the researchers at Fermilab's Tevatron collider are getting closer to the big prize. Just this week, they reported the first detection of single top quarks, which is a significant accomplishment in itself and also advances the search for the Higgs. Last year, Fermilab reported results that narrowed down the energy range where the Higgs might lurk, and Lincoln told me there are new results in the works that will improve upon those previous results.
"Knowing where not to look is an important piece of the puzzle," he said.
Knowing what not to expect from the LHC is just as important, particularly when it comes to planet-destroying catastrophes. In the prologue to "The Quantum Frontier," Lincoln addresses the widely reported worries over microscopic black holes, strangelets and other nightmare scenarios - and he explains why "it is impossible that any of these scenarios are true." Essentially, the reason is that many, many reactions much more energetic than the LHC's collisions have occurred over a span of billions of years. The fact that we're still here is an indication that we're safe, Lincoln said.
"If you do the arithmetic, you'll find that you'd have to run the LHC for 100,000 years in order to have the same collisions that the universe has brought to Earth already," he said. "People do worry about this, and I think it's a completely fair question. But when you think about it for a little while, you see that there's absolutely no reason to be nervous."
For more about Lincoln, the LHC and the quantum frontier, check out Lincoln's collection of online presentations, as well as this podcast from "Lab Out Loud."
Here are a few extra tidbits from the world of particle physics:
- More books about the LHC are on the way: LHC project leader Lyn Evans' work, "The Large Hadron Collider," is reportedly due for publication in June. Paul Halpern, a physicist and mathematician at the University of the Sciences in Philadelphia, is coming out with "Collider: The Search for the World's Smallest Particles" in August. And for something completely different, check out this online publication called "The Little Book of the Big Bang."
- A federal lawsuit raising concerns about those doomsday scenarios was dismissed last year, but the plaintiffs filed an appeal, and the federal government was supposed to file its response by the end of last week. A spokesman for the Justice Department, Andrew Ames, told me today that government lawyers have asked for more time to prepare their brief, but the court has not yet ruled on that request.
- The LHC is going to get some screen time in "Angels & Demons," a movie based on Dan Brown's thriller. The US LHC users' group is already gearing up to use the film, due to premiere in May, as an opportunity to educate the public about particle physics. Watch this space for more to come. And watch for a little extra star power when the LHC is ready for its restart. Actor Tom Hanks, the star of "Angels & Demons" as well as "The Da Vinci Code" and loads of other movies, is supposed to help push the button.
Update for 1:15 p.m. ET March 11: Fermilab just announced that its DZero team made an high-precision measurement of the mass of the W boson, which will in turn help narrow down mass estimates for the Higgs boson. If you must know, the exact mass of the particle measured by DZero is 80.401 +/- 0.044 GeV/c2. Click on over to the Symmetry Breaking blog for more information (plus a cute picture that actually helps explain what's going on).
Update for 12:30 p.m. ET March 13: But wait, there's more: Fermilab researchers report that they have excluded still more places where the Higgs boson may lurk. The latest findings suggest that the Higgs' mass should be between 114 and 160 GeV/c2, or between 170 and 185 GeV/c2. That is, if it exists at all. Once again, get the full story from Symmetry Breaking.
Check out our special report on "The Big Bang Machine" for 360-degree views, interactives that explain the LHC's workings, expert commentary on the nightmares and dreams generated by the LHC, and much, much more. And speaking of much, much more ... here are more postings about Big Science:
