Charm, Beauty, and Beyond

To search for the possible existence of the fourth generation of quarks, it is best to begin what we know for sure, which then can serve as a base for making guesses at what is coming. Here I shall report mainly the recent work done with Hai‐Yang Cheng analyzing the recent data of exclusive two‐body charm decays, and extracting their theoretical implications as well as pointing out future interesting experiments, based upon the quark diagram scheme. Using the same approach, we also classified the rare charmless beauty particle decays and estimated their branching ratios. We also pointed out decay channels of B meson decays with large partial decay rate differences for experimental search. Finally we emphasize again that it is possible for charm particle decays to have large partial decay rate differences if the fourth generation of quark exists. Of special interest are those partial decay rate differences coming solely from the tree‐diagram interferences, which depends only on the existence of the fourth generation of quarks but not on their masses. It is therefore important to search for such charm, partial decay rate differences.