San Diego Union-Tribune
February 8, 2007
In science, anything worth talking about must be testable. That is, I can blather all I want about extraterrestrial life in the universe, but unless and until I can test for it, I'm not talking science.
This demand for empirical proof has long undermined one of the more compelling ideas in physics, the one about the building blocks of the universe not being particles of matter or energy, but rather tiny, one-dimensional filaments called strings.
The big problem with string theory, sometimes grandly dubbed the â€œtheory of everything,â€ has been that it has not been testable. Physicists have debated endlessly about how these strings might behave, about the possibility of 10 or more dimensions, about all manner of mind-bending stuff, but they have always lacked the means to prove or disprove their predictions.
That may change later this year when a new particle smasher called the Large Hadron Collider (LHC) comes on line at the European Laboratory for Particle Physics, or CERN, in Switzerland.
The collider will be able to measure how subatomic particles called W bosons scatter in high-energy collisions created within the accelerator. W bosons are notable because they possess a property called the weak force, which provides a fundamental way for particles to interact with each other.
String theory makes specific predictions about how W bosons should scatter. With the LHC in mind, researchers at UCSD, the University of Texas at Austin and Carnegie Mellon University have devised a test to see if those predictions are actually based in reality.
â€œIf the test does not find what the theory predicts about W boson scattering,â€ said UCSD physics professor Benjamin Grinstein, â€œit would be evidence that one of string theory's key mathematical assumptions is violated. In other words, string theory â€“ as articulated in its current form â€“ would be proven impossible.â€