This is Samuel Ting’s second lecture held at the Lindau Meetings, three years after the first one. The two lectures are connected and tell more or less the same story, the story of a travelling high-energy physicist, who moves from one accelerator to another in search of higher and higher energies. Ting seems immediately to have understood the idea behind the Lindau Meetings and, as a number of other Nobel Laureates, fallen in love with it. Understanding the idea partly means that he knows that most of the students and young researchers in the audience are different from meeting to meeting. So he could in principle tell more or less the same story every time. But Ting, even as a Nobel Laureate, is an extremely active physicist and he cannot resist telling the latest news from his work. So after an historic introduction, involving a long list of Nobel Laureates such as Rutherford, Yukawa, Hofstadter, Gell-Mann and Taylor, he concentrates on his own work. This involves the discovery of the 4th quark, the charm quark, for which he received the 1976 Nobel Prize in Physics together with Burton Richter. He then moves on to the work he has done looking for more quarks, since at the time of the lecture the number of quarks was still an open question. The 5th quark had been discovered, but Ting could not find any signs of the 6th quark. So he instead brings up the question of how large the quarks are and concludes that according to his experiments they are pointlike. At the PETRA accelerator in Hamburg, where very high energy beams of electrons and positrons were made to collide, he worked in a team which discovered the so-called three jet events. These are signatures of the existence of the carrier of the strong force, the gluon. The discovery of the gluon has not been recognised with a Nobel Prize in Physics, maybe because there were so many collaborators in the experiments. So far (2012) the physics prize has not been given to whole groups. Anders Bárány |