Interactions Between Baryon And Baryon With Strangeness Being-2

Quantum chromodynamics（QCD）is the basic theory of strong interaction,and the phenomenological models with QCD spirit—chiral SU（3）quark model（χ-SU（3）QM）and extended chiral SU（3）quark model（Ex.χ-SU（3）QM）have achieved very good results when studying the structures of hadrons and strong interactions.Inspired by H particle,this thesis have studied the interactions ofΛΛ,NΞandΣΣdibaryon systems with strangeness being-2 by resonant group method（RGM）in the framework of these two quark models.We first study the effective potentials and binding energies of theΛΛ,NΞandΣΣsystems with different spins and isospins.The results show that:1)TheΛΛ_（0,0）andΛΛ_（1,0）systems cannot form bound states in the above two models,which is consistent with results from other theoretical methods.The internal medium-range interactions of these two systems are relatively weak attraction,which mainly comes fromσmeson exchange.The short-range behaviors of single gluon exchange（χ-SU（3）QM）and vector mesons exchanges（Ex.χ-SU（3）QM）are similar and they are repulsive.2)The NΞ_（0,0）system can form a bound state in the two models,and its binding energy is about 21-33 MeV.The effective potential of the NΞ_（0,0）system is strong attraction,and the short-range one gluon exchange（χ-SU（3）QM）is relatively weak attraction and vector mesons exchanges（Ex.χ-SU（3）QM）are repulsive forces.Therefore,this attraction is mainly provided byσmeson exchange.NΞ_（1,0）,NΞ_（0,1）and NΞ_（1,1）systems cannot form bound states in two models.The internal interaction of these three systems are relatively weak attraction in the middle-range part,which is mainly provided byσmeson exchange;The short-range behaviors of single gluon exchange（χ-SU（3）QM）and vector mesons exchanges（Ex.χ-SU（3）QM）are similar and they are repulsive.Our current results show that the NΞ_（0,0）bound state is crucial for understanding the structure of H-particles.3)TheΣΣ_（0,0）andΣΣ_（1,0）systems are bound states in two models,and their binding energies are 15-26 MeV and 22-62 MeV,respectively.The internal interactions of the two systems are relatively strong attraction,and the attractive force of theΣΣ_（1,0）system is greater than that of theΣΣ_（0,0）system.In theΣΣ_（0,0）system,the short-range behaviors of single gluon exchange（χ-SU（3）QM）and vector mesons exchanges（Ex.χ-SU（3）QM）are similar,and they are attractive;The medium-long-range part is mainly due toσmeson exchange.In theΣΣ_（1,0）system,the single gluon exchange（χ-SU（3）QM）is repulsive,and the vector mesons exchanges（Ex.χ-SU（3）QM）are attractive,which means that their short-range behaviors are different;the medium-long-range interaction mainly comes fromσmeson exchange.The results of the study show that the single channelΣΣ_（0,0）is important for understanding the structure of H particles.4)TheΣΣ_（0,1）,ΣΣ_（1,1）andΣΣ_（0,2）systems cannot form bound states in both models.The internal interactions of these three systems are relatively weak attraction in the middle range,which mainly comes fromσmeson exchange.The short-range behaviors of single gluon exchange（χ-SU（3）QM）and vector mesons exchanges（Ex.χ-SU（3）QM）are similar and they are repulsive.At the same time,we also study the S-,P-and D-wave scattering phase shifts,total scattering cross sections and contributions of S-,P-and D-wave to total cross section of all the above systems and find that the information given by the S-wave scattering phase shifts is qualitatively consistent with that from the systems’interactions and bound energies,the P-wave interaction is weak,and the D-wave has no effect at all;The S-wave contributes the most to the total cross section,the P-wave contribution is relatively small,and the D-wave has almost no contribution.