The experiments are forcing us to try to understand the theory in places where the calculations are difficult.'' Chris Quigg, a particle theorist at the Fermi National Accelerator Laboratory in Illinois, said: ''It's only a theory of everything if you can explain all the things. With a good-natured dig at ambitious theoretical efforts to unify the forces in the Standard Model (strong, weak and electromagnetic) with gravitation, Dr. Just to make things as complicated as possible, there are eight different kinds of gluons, each with a different type of ''charge.'' And there are six varieties of quarks, each with its own cute name: up, down, top, bottom, charm and strange. That habit means that heavy particles like protons and neutrons are also filled with these more evanescent quarks winking in and out of existence. They spend part of the time in the guise of other quarks. The swarming particles that transmit the strong force from quark to quark, called gluons, are shape-shifters. They can never escape the sticky embrace of another quark. That is because the strong force does not become weaker - in contrast to gravity or electrical forces - the farther the particles are apart. Although physicists know that protons and neutrons are made of groups of three quarks, not even these great demolition experts of science have been able to knock a quark free.
It is not hard to see why a full understanding of the strong force has eluded theorists for decades. A multibillion-dollar, multinational collaboration in Geneva called the Large Hadron Collider is not expected to be ready before 2007.īut then, he said, ''Here this thing comes in from left field.'' In 1993, Congress killed the Superconducting Super Collider, a vast particle accelerator that was to have begun collecting data by this year. The discoveries are especially welcome in a field that is in some ways adrift, lacking any big new machine to smash matter into ever-finer pieces. ''These three discoveries are very important hieroglyphs.'' ''We need more hieroglyphs to decode them,'' he said. Close likened scattered clues on the way the strong force works to undeciphered hieroglyphs. Frank Close, a professor of theoretical physics at Oxford University in England.ĭr. ''We don't understand how this force really works when it gets very strong - when it makes atomic nuclei, for example, or makes these particles,'' said Dr. Either way, the rush of results is expected to lend fresh insights on the strong force, widely considered among the most opaque and intractable parts of the Standard Model, the theory physicists use to explain matter's basic structure. The finding at KEK, which followed a related discovery at the Stanford Linear Accelerator Center this year, could also turn out to be a rare combination of just two quarks called charmonium, some theorists believe. Although quarks normally congregate in twos and threes, several laboratories said this summer that they were seeing what appeared to be ungainly clumps of five quarks. Hints of those strange creations began turning up this year. But theorists have long suspected that the strong force has a wild side and that it should be able to take the subatomic equivalent of a Tudor chimney here, an Art Deco facade there, and stick them together into entirely new particle types. The glue linking these discoveries is the ''strong force,'' which is normally relegated to holding together quarks, the building blocks of humdrum particles like protons and neutrons. So it may come as a surprise that the field has recently found a powerful new engine of discovery: gluing it all back together again, sometimes in weird ways that seldom occur in nature, if ever. Particle physicists are known as the demolition crews of the very small, smashing tiny bits of matter together to find the even tinier bits that they are made of.