The top quark is by far the heaviest elementary particle known. A measurement of its mass with higher precision has bearing on our understanding of the fundamental interactions of nature,The basic building-blocks of matter, as I far as we know, are quarks and leptons, I together with the force-carrying par ticks that mediate their interactions. Quarks and leptons (the latter group including the electron) are grouped in three generations;the particles in the second and third generations seem a perfect copy of those of the first generation, except that their masses are much larger, The top quark is the heaviest of all quarks and leptons, and is central to some of the most pressing questions in particle physics. For instance, why is the thir d-gener -ation top quark more than 300,000 times heavier than the first-generation electron? Why are there two other quarks with precisely the same properties as the top quark but with very different masses? And what is the origin of mass itself?
展开▼
