Exploring The Hadronic Transitions Of Quarkoniums Via Hadron Loop Mechanism

In the past decade,experimentalists have found large amounts of anomalous phe-nomena when studying the hidden-flavor decays of highly excited quarkonia.For ex-ample,Belle collaboration found that all the branching ratios of the hidden-bottom de-cays of T(5S)are around 10-3.Also,BESⅢ and Belle collaborations announced that they observed a series of charged charmmonium-like states Zc(3885),Zc(3900),Zc(4020),2,(4025)and charged bottomonium-like states Zb(10610),Zb(10650).All these anomalous phenomena indicate that the hadron loop mechanism plays an important role in the hidden-flavor decays of’ highly excited quarkonia.Thus in this thethis,we sequentially use the hadron loop mechanism to study the hadronic transitions of highly excited quarkonia,which include studying the hidden-bottom decays of T(6Sf),exploring the production of T(2D)and T(3-D),using ISPE(Initial Single Pion Emission)mechanism to explain the charged structure appeared in theΨ(3686)π± invariant mass spectrum of the e+e-→Ψ(3686)π+π-process that was observed by BESⅢ.Since the effective Lagrangian approach is adopted to make our calculation,first we make some instructions on the effective field theory,which include the basic idea of effective theory,the heavy quark symmetry,the chiral symmetry,the NRQCD and the constructions of the Lagrangians that describe the interactions between heavy flavor mesons and light mesons or heavy quarkonia.Since BelleⅡ is running,considering the experimental information of Υ(6S)’s hidden-bottom decays is absent in PDG(Particle Data Group),it is necessary for us to carry on a series of researches on Υ(6S).Thus in this thethis,the T(6S)→XbJ(?),Υ(6S)→XbJω,T(6S)→Υ(nS)η(’)and T(6S)→ T(1D)η(’)processes are explored via hadron loop mechanism and the branching ratios of above processes in addition to the rates between them are given.After analysing our theoretical results,we believe that it is very possible to find T(6S)→XbJ(?),Υ(6S)→XbJω,Υ(6S)→Υ(nS)η(’)and T(6S)→Υ(1D)η(’)processes in the future experiments such as BelleⅡ,which will help us understand the properties of Υ(6S)more deeply.Also,our results show that the rates between the branching ratios are weakly dependent on the αΛ appeared in the form factor,which is important for experiments to test the hadron loop mechanism.We want to emphasize here that,in 2018,Belle announced their observations of T(6S)→XbJ(?)and Υ(6S)→XbJωprocesses,and the experimental results are consistent with our predictions.Then,the possibilities of finding missing T(2D)and T(3.D)in BelleⅡ are investi-gated.By reading BelleⅡ physic.s book,we notice that BelleⅡ can search for T(2D)via scanning the ππ missing mass spectrum of T(6S)and find Υ(3D)via scanning the cross sections of e+e-→ hn(1p)ηande+e-→Υ(1S)η processes.Since T(6S)and Υ(3D)are above BB threshold,T(6S)→T(1D)ππ,Υ(6S)→T(2D)ππ,Υ(33DJ)→hb(1P)ηand Υ(33DJ)→Υ(1S)。processes are explored via hadron loop mechanism.Our results show that under BellelI’s experimental environment,experimentalists must be able to observe Υ(2D)in the ππ missing mass spectrum of Υ(6S).Also,we find that BelleⅡ can find π(33D1)via scanning the cross sections of e+e-→hb(1P)η and e+e-→Υ(1S)ηprocesses and find Υ(33D2)by searching the cross section of e+e-→Υ(1S)η process.As for the discovery of Υ(33DJ),we still need to find other approaches.Finally,with the help of ISPE mechanism,we explain the charged structure appeared in the Ψ/(3686)π±invariant mass spectrum of the e+e-→Ψ(3686)π+π-process observed at BESⅢ.A model that includes the ISPE mechanism is used to do a combined fit on the cross section in addition with Ψ(3686)±π±and π+π-invariant mass spectra that lie on 6 different energy points of e+e-→Ψ(3686)π+π-process given by BESⅢ.The fit results show that by just one set of parameters,even though we do not introduce any charged resonances,the cross section in addition to all the Ψ(3686)π±and π+π-invariant mass spectra of e+e-→Ψ(3686)π+π-process can still be reproduced well.Especially,the charged structure around 4.032 GeV can be reproduced nicely.Thus in our view,the charged structure that observed by BESⅢ might be a result of ISPE mechanism.In a word,by using hadron loop mechanism,we not only explore the decay and production of heavy quarkonia,but also carry on some studies on the charged quarkonium-like states.If the future experiments can test our calculation,it will help us more deeply understand the role that hadron loop mechanism plays in the transitions of hadrons.