Study On The Meson Loop Effect In The Decay Of Bottom Quarkion

Quantum Chromodynamics?QCD?is regarded as a theory describing the strong interaction,which have made more significant achievements in heavy-quarkonium physics.The productions and decays of bottom-quarkonium physics,serves as an important probe for understanding the nature of Quantum Chromodynamics in both perturbative and non-perturbative regime in particle physics.In this thesis,with the latest measurement results of BELLE Collaboration,we applied the model of intermediate meson loops to study the coupled-channel effects in the hidden-bottom decays of some bottom-quarkonium states,systematically.In this thesis,we first introduce the particle physics history simply,which include the field theory,the general particles,the fundamental interactions,the conventional quark model,and the exotic states.In the research method part,we simply introduce Quantum Chromodynamics,the effective field theory,and the intermediate meson loops model,respectively.In the phenomenological study,this article mainly includes the following two aspects of ??4S,5S,6S??h_b?1P??transition mechanism:1.Based on effective Lagrangian approach?ELA?,we mainly explored the hidden-bottom hadronic transitions of ??4S,5S,6S??h_b?1P??systematically and present branching fractions.Our results have shown that the branching fractions for ??4S??h_b?1P??are orders of 10^-3with reasonable cutoff parameter rangea?26?0.15?25?0.25,and the experimental data can be reproduced in this approach.We then explored the decays of ??5S,6S??h_b?1P?? in the same way and find that these two channels also have sizable branching fractions.For the decay of ??5S??h_b?1P??,the results are about orders of 10^-3?25?10^-2.The results of ??5S??h_b?1P?? are about orders of 10^-4?25?10^-2.These hidden bottomonium decay modes are of great importance in the experimental study of ??nS,n?28?3,4,5?,and we also suggest future experiment to search for these decays of ??5S,6S??h_b?1P??,which will be helpful to understand the transition mechanism.2.In the framework of non-relativistic effective field theory?NREFT?,we calculated these ??4S,5S,6S??h_b?1P??processe's branching fractions.For the decay ??4S??h_b?1P??,the NREFT results are at the same order of magnitude but a little smaller than the effective Lagrangian approach?ELA?results.For the decays ??5S??h_b?1P?? and ??6S??h_b?1P??,the NREFT results are smaller than the ELA results by approximately one order of magnitude.We expect a future experiment Belle-II to carry out the search for this anomalous transitions phenomenon,which will help us to test this point.Finally,I give a summary and prospects for future's research.