Bulletin Number Two 1987

Interview with Professor Samuel C.C. Ting The following is a record o f an interview with Pro fessor Samuel C.C. Ting on 25th March ， 1987 at the University by Dr. Kenneth Young, Reader in Physics ， and the Editor ， Chinese University Bulletin. Q. You were awarded the Nobel Prize in Physics in 1976 fo r the discovery o f the J-particle. Would you like to explain to our readers what led to the discovery o f this heavy elementary particle and what is the significance o f your discovery? A. One of the main purposes of the work of a physicist is to find out what is the fundamental building blocks of nature and what is the basic constituent of matter in the universe. In ancient China, people took gold, wood, water, fire and earth to be the five elements of the universe. Gradually people realized that there are many chemical elements like iron, mercury, etc. and by the 17th century, they began to know the chemical elements. Indeed by the end of last century, through the work of Dmitri Mendeleev, they came to know that there is a periodic table. So, at the beginning of this century, we viewed the world as being made of about one hundred chemical elements; we call them the building blocks of nature. And then, electrons were discovered and the nucleus of the hydrogen atom, in other words the proton, was discovered. This led to a change of our concept from a few hundred basic elements to two basic building blocks — electrons and protons. Subsequently more and more proton type of particles were discovered, and by 1960 ， we came to know of a few hundred subatomatic particles, such as heavier electrons such as muons ， and protons, neutrons, kaons ， etc. At that time, we changed our concept again, taking the few hundred sub­ atomic particles as the basic building blocks of nature. In 1964 ， people began to think that maybe the world is made of smaller building blocks known as quarks and began to construct a theory. According to the theory most of the elementary particles or subatomic particles are made of three types of quarks. And that indeed could explain most of the phenomena, practi cally all of them. In 1974, my group did an experiment leading to the discovery of the J- particle. The J-particle is very different from all the few hundred subatomic particles in two senses. First, it is much heavier, and second, it lives much longer. It lives about ten thousand times longer than other particles. Now, why is it much heavier? And why does it have such a long lifetime? The explanation is that the J- particle does not come from the three quarks but from a new quark. So, that work of ours shows that there must be a fourth quark, and that three quarks cannot make up the world: there must be four. But if you have four, there could be five, six and so on, I was awarded the Nobel Prize mainly for that work. INTERVIEW 17