Study Of The Structure Of X_b

In particle physics,heavy quark physics excite researcher ’s interest both in theoretical and in experimental aspects. Because there are very rich dynamical mechanism in the heavy quark physics decay process. This also caused the researchers great interest to study these dynamic mechanism. In fact, we can introduce some problems of heavy quark physics briefly from the opinion of Quantum Chromodynamics. We can see from Quantum Chromodynamics that the hadron structure allowed by Quantum Chromodynamics is: Q =(q (?))~n(qqq)~mg~l. But in fact, we cannot explain the baryon and meson clearly,which are predicted by conventional quark model. Although some exotic states of hadron are discovered in experiment, unfortunately, we still don’t know the structure and nature of these hadron state. Researchers are searching for new states of hadron both in experimental and theoretical ways. One of them is famous X(3872), which excites great interest of researcher to study these exotic state of hadron. But many years passed, we still don’t know its structure and nature. In the theoretical circle, different models are constructed by different groups to explain this exotic state of hadron. There are some more famous models: molecular state, hybrid state, glueballs, multiquark states and so on.Perturbation method could not be applied in low energy Quantum Chromodynamics, the main method used in the low energy Quantum Chromodynamics is lattice Quantum Chromodynamics, due to the high requirement to computer, Because it just supply unsatisfactory results. An important problem waiting to be solved is how to understand these exotic state of hadron. The main method in theoretical side is constructing phynomenological model of Quantum Chromodynamics to understand them. There are some more famous models: multiquark state, hybrid, glueballs, molecular state and so on.A very important field of heavy quark physics, the dynamical mechanism of heavy meson lies in the process of its decay. This article explore its structure and nature through the decay of X_b, our study indicates that the bound state Z and binding energy B areimportant for understanding the structure of X_b. Therefore the line shape measurement can help us to identify the structure of X_b. We cannot simply put X_bto be a molecular state, although the mass of X_bis very close to B*(?) threshold.