| Feature | May. 15, 2008 | 12:23 am |
Exploring the Standard Model of particle physics
By
At the end of my high school Quantum Mechanics class, our teacher gave each of us a poster of the Standard Model of particle physics. It’s a sweet poster. The diagrams of particle clusters and clouds are pretty, and the charts are fun to read. Particle categories and names (fermion, boson, neutrino, muon, quark, lepton, baryon, meson, gluon…) beg to be used in bad puns or knock-knock jokes. And, in addition to the mass and charge attributes we saw in chemistry class, these particles have “spin” and “flavor.”
But that’s about as far as my understanding of the Standard Model goes. Assistant Physics Professor Andre de Gouvea, on the other hand, comprehends the Standard Model beyond its sheer grooviness. Inside his office, a bike leans against a bookshelf full of physics texts, and a cascading cluster of lanyard nametags from science gatherings hangs from a file cabinet. When he’s not teaching a physics class or guiding students through research, de Gouvea investigates the results of particle physics experiments, especially those involving neutrinos — they’re quick, light elementary particles.
With a slight Portuguese accent from his native Brazil, he calls the model an “ad hoc, weird-looking theory” that has never been perfect, as his investigations helped reveal. The model states that neutrinos have no mass, but in 1998, experiments showed that they did. Such contradictions to the Standard Model, de Gouvea says, are cause for celebration rather than consternation. “We’re always on the hunt to find things that violate it so we can get a better idea of what the right picture should be.”
Nothing excites a particle physicist as much as the device that will present a clearer view of that picture: the Large Hadron Collider (LHC) at CERN, a nuclear-research facility in Geneva, Switzerland. The LHC, which should be ready for operation this summer, will bang together protons and other particles in an underground tunnel 17 miles in circumference. These collisions could produce the heavy Higgs boson, dubbed the “God particle” due to its massive implications for the Standard Model and science as we know it.
The development of physics’ Standard Model runs along the same lines as the development of chemistry’s periodic table in the 19th century. Scientists seek an ultimate logical organization, but inconsistencies arise. The model can only approach perfection through time and research. Right now, as de Gouvea’s research helps show, the Standard Model remains incomplete.
One big reason the Standard Model comes up short: It doesn’t explain “dark matter.” The name itself sounds ominous, like some trick of Lord Voldemort. Dark matter, which is invisible, somehow accounts for gravitational force. “Whatever it is, it’s not normal matter,” de Gouvea says. Dark matter is probably made of a new, un-observed fundamental particle, he says: “And whatever that new particle is, it’s not something that belongs in the Standard Model.”
Why bother perfecting this bear of a model? The Standard Model could give us crucial insight into the universe’s first moments. Initially, the universe was so hot and dense that it looked like a giant bag of fundamental particles, de Gouvea says. “We have to know what their properties are in order to understand why we live in a universe that looks like it does when we observe things.”
Besides shedding light on the birth of the universe, developing a better Standard Model might contribute to a “Theory of Everything,” the Golden Fleece for scientists. A theory of everything would elegantly explain why nature works the way it does. Could all of these different particles and interactions really be manifestations of one grand, underlying principle?
While the LHC will provide some answers, some worry that it might also produce tiny black holes that could swallow the earth. But the probability of this happening is so small that it’s not worth being concerned about. Other apocalyptic fears include the production of some strange matter that would react with other matter and transform the earth into a dense ball of sameness (like Kurt Vonnegut’s “ice-nine,” the catalyst of the apocalypse in Cat’s Cradle).
These scenarios won’t occur, de Gouvea says, because the LHC won’t create a situation that hasn’t already arisen in nature. Particles in cosmic rays, for example, could have transformed Earth — but they haven’t. “It’s sort of science fiction,” he says, and the potential benefits of using the LHC far, far outweigh the risks.
What did one particle physicist do to the guy who claimed the LHC would destroy the universe?
He lepton him.
JTankers said,
May 15, 2008 @ 7:50 am
“the potential benefits of using the LHC far, far outweigh the risks”
According to CERN, there are no risks. But it is also possible that the risks of creating a micro black hole may approach 100% above a certain energy.
I find it diffucult to comprehend how a stray cosmic ray (a rare proton traveling so fast as to have energies as high as 10^20 eV) hiting a single relatively stationary particle on Earth, even if the impact was exactly center mass, could create the same conditions as a head-on particle collider collission where powerful magnetic fields laterally and oppsing momentums of thousands of protons or protons to anti-protons traveling in exactly opposite directions at 99.9999991% the speed of light collide in head-on collissions designed to focus the energies between the particles on impact.
Where in nature are these conditions replicated?
Thank you,
JTankers
LHCConcerns.com
JTankers said,
May 15, 2008 @ 8:00 am
(Slightly Corrected…)
“the potential benefits of using the LHC far, far outweigh the risks”
According to CERN, apparently there are no risks.
However it is also possible that the probabilities of creating micro black holes in head-on collider collisions of LHC energy levels may approach 100%.
I find it difficult to comprehend how a stray cosmic ray (a rare proton traveling so fast as to have energies as high as 10^20 eV) hitting a relatively stationary particle on Earth, even if the impact was exactly center mass, could create the same conditions as head-on particle collider collisions where powerful magnetic fields laterally and opposing momentums of thousands of protons or protons to anti-protons traveling in exactly opposite directions at 99.9999991% the speed of light collide in head-on collisions designed to focus the energies between the particles on impact.
Where in nature and how frequently in nature are these conditions replicated?
Thank you,
JTankers
LHCConcerns.com
Lauren C. Ruth said,
May 15, 2008 @ 2:10 pm
Hi JTankers,
True, the LHC’s method of smashing particles together differs from nature’s, but the results are the same. The magnetic fields employed in the LHC create dense particle beams that optimize the natural situation rather than changing it. These streamlined beams lead to a higher chance of producing head-on collisions than cosmic rays do.
Cosmic ray collisions occur at higher energies than those induced by the LHC (on the order of 10^20 eV vs. 10^12 eV). Most importantly, cosmic ray collisions have greater “center-of-mass” energies — the amount of energy available for creating new particles, and therefore the quantities that would produce potentially catastrophic phenomena (on the order of 10^15 eV vs. 10^12 eV).
The question is, Have enough extremely high-energy cosmic ray events taken place in history that we can bet they won’t lead to the apocalypse? Considering cosmic rays have occurred on earth and elsewhere since the birth of the universe, this is statistically a fairly safe assumption.
Hopefully that helps; I’m no expert on particle physics. You might also be interested in this article on the LHC risk debate by New York Times science writer Dennis Overbye at http://www.nytimes.com/2008/04/15/science/15risk.html
JTankers said,
May 15, 2008 @ 8:44 pm
Thank you Lauren Ruth, I read the article you recommended. (http://www.nytimes.com/2008/04/15/science/15risk.html)
Article quote: “But the chance that such a black hole would not instantly evaporate according to a theory famously propounded by Stephen Hawking in 1974 is even more weirdly unlikely, the theorists say”.
I did some research, and the following physicists published peer reviewed papers that question claims that micro black hole might evaporate before they grow:
Dr. Adam D. Helfer: xxx.lanl.gov/abs/gr-qc/0304042
Dr. William G. Unruh and Prof. Ralf Schützhold: arxiv.org/PS_cache/gr-qc/pdf/0408/0408009v2.pdf
Prof. V.A. Belinski: ingentaconnect.com/content/els/ 03759601/1995/00000209/00000001/art00785
Dr. Adam D. Helfer: arxiv.org/PS_cache/gr-qc/pdf/0503/0503052v1.pdf
The article also reads “Cern’s most recent safety report, in 2003, focused mostly on refuting the strangelet threat in the hadron collider and devoted just three pages to black holes, saying they “do not present a conceivable risk.””
CERNs web site refers to the 1999 RHIC safety study which also determined zero risk from micro black holes, because it was determined that creation of micro black holes was not possible at collider energies. However physicist, and CERN themselves, have changed this prediction from no chance to ‘not unexpected’.
And the 1999 RHIC Safety report did not address the risks if micro black holes were actually created. It did not address accretion time, capture rates, or the possibility of evaporation. It just did not address these issues at all.
Sor CERN now predicts that micro black holes might be created at a rate of one per second, that is what they posted on there Safety web site earlier this year. And CERN still attests to the fact that micro black hole creation will not be an unexpected event when collissions begin. But they do assure us that even if micro black holes do not evaporate, they will grow too slowly to pose any concievable threat to Earth during Earth’s 5 billion year expected life time. And CERN will produce proof to this effect soon, they are still working on the proof.
However, one of Germanies more famouse scientists, Dr. Otto E. Rossler, father of Chaos theory calculates that a single micro black hole might accrete the Earth in as few as 50 months: wissensnavigator.com/documents/OTTOROESSLERMINIBLACKHOLE.pdf
But colliders are not the only type of experiment that might be capable of creating micro black holes. In fact if you ask ask Nobel Laureate Dr. Eric A. Cornell, who leads Bose-Einstein condensate research at the University of Colorado, if creation of a micro black hole might explain thousands of missing atoms after an unexplained (bosenova) implosion of a “super atom” containing 16,000 atoms at 3 nk (3 billionths of a degree above absolute zero). He may tell you that more likely there is an alternate explanation, but no alternate explanation that he can fully explain. nobelprize.org/nobel_prizes/physics/laureates/2001/cornellwieman-lecture.pdf
I also know that the LHC Safety Assessment Group (LSAG) has conceded that cosmic ray impacts with Earth would send all particles safety into space so cosmic ray impacts would not pose a threat to Earth. LSAG has also acknowledged that they do not assume that micro black holes will evaporate for the purpose of risk assessment, though they believe that is what will happen.
I also am not an expert in particle physics. But I do have a hard time understanding why we should be assured that there is no conceivable threat, when by my ‘back of the note book’ calculations, I can imagine that the threat might be as high as 100%. Or as low as zero percent, and reasonable and credible physicists do not agree.
It seems reasonable to me then, that a safety study should least address the risks that micro black hole creation an capture by Earth’s gravity might pose. And further, it seems reasonable to me that such a study be rigorously, independently and widely peer reviewed over a reasonable period of time before we find out if the risk was closer to 100% or closer to 0% by actually possibly creating micro black holes and watching to see what happens. That sounds reasonable to me.
Thank you,
James Tankersley Jr.
Co-Moderator, LHC Concerns.com, web site for laypersons
JTankers said,
May 15, 2008 @ 8:51 pm
Corrections: So not Sor, their not there and Germany’s not Germanies…
Jesus said,
May 15, 2008 @ 9:03 pm
What is wrong with CERN ending the world?
Macharius said,
May 18, 2008 @ 12:00 pm
Well, the only problem I can see is that its hard to understand the universe if we’re all dead and gone.
Personally, I believe that the Earth won’t be destroyed. Similar claims were made about they hydrogen bomb (that it will burn up all the oxygen in the atmosphere upon detonation, and other such nonsense).
If the earth IS destroyed, with my dying breath I’ll remember you, JTankers :).