The Symmetry Analysis Of Heavy Flavored Hadrons And Interactions Between Light Hadrons

Phenomenological hadron physics has great guiding significances in understanding the non-perturbative QCD.With the accumulation of experimental data in recent years,great progresses have been made in observing the excited heavy-flavor mesons,heavy-flavor baryons,and candidates of tetraquark and pentaquark states,providing us rich contents on studying phenomenological hadron physics.In this thesis,we first study systematically the mass spectra of QQQq systems based on SU(3)symmetry.The color-magnetic interaction(CMI)model is applied to study the explicitly exotic states ccbq,bbcq,and the hidden exotic states cccq,cbbq,bccq,bbbq.If a state around the estimated mass region could be observed,its nature as a genuine tetraqua,rk is favored.Then we further study the mass splittings of the qqQQ(q=u,d,s and Q=c,b)tetraquark states with the color-magnetic interaction by considering color mixing effects and estimate roughly their masses.We find that the color mixing effect is relatively important for the JP=0+ states and possible stable tetraquarks existing in the nnQQ(n=u,d)and nsQQ systems either with J=0 or with J=1.Possible decay patterns of the tetraquarks are briefly discussed.Next,as an application of heavy quark symmetry,all the heavy-light systems are analysed using the Regge-like formula(M-mQ)2=??L.The included systems are D/Ds/B/Bs mesons and charmed/bottom baryons.Assuming the light part(light quark or light diquark)in meson/baryon as one light cluster,we present the results for the corresponding systems obtained from Regge-like formula.We notice that the obtained slopes of heavy-light systems in Regge-like formula are nearly half of that for light hadrons,which approximately satisfies the requirement of heavy quark symmetry.Our results on baryons suggest that these baryons can be safely regarded as(heavy quark)-(diquark)configurations.Then we present the study on the production of D-wave D(s)excited mesons via B(S)meson semileptonic decays.Our calculation shows that the production rates of D-wave D(s)are considerable,and we expect more efforts can be paid on these processes in future experiments.In addition,we compare the calculated numerical form factors with those of the heavy quark effective theory,and our results are consistent with the requirements from heavy quark symmetry.The next two chapters are devoted to studying the possible inner structures of the?(1620)and ?(1670).In 2019,the Belle Collaboration firstly observed the ?(1620)in the?c non-leptonic decay process.This observation motivate us to study the K? system in the framework of one-boson-exchange model.Our results indicate that ?(1620)0 can be explained as a K? molecular state with quantum numbers I(JP)=1/2(1/2-).In the study of the ?(1670),two scenarios for the inner structure of the ?(1670)are presented.One describes the,(1670)as a dynamically generated state from the interactions of isospin-0 coupled channels ?? KN,?? and K?.In the other scenario the ?(1670)is assumed as a bare triquark-like baryon basis mixing with the interactions of meson-baryon coupled channels.By fitting the K-p scattering data,the pole structures of the A(1405)and ?(1670)can be produced well simultaneously in both scenarios.We further compare the finite-volume hamiltonian spectrums based on both scenarios to lattice QCD calculations,our results indicate that the inner structure of the ?(1670)is a quark-model-like baryon basis mixing with the meson-baryon interactions.