The Structure Of Light Hyper Nuclei Based On Few-body Approach

hypernuclei are nuclei with hyperon included,such as ?,?,? or ?.Studying the structures of hypernuclei and the underlying interaction inside hypernuclei enriches our understanding of the physics and most importantly,offering more information about the baryon-baryon interaction.From the nuclear side,we can investigate multiple baryons' feature more than proton and neutron.All of the observed hypernuclei so far are mostly light ones with A<30.Therefore,one of the main focuses in hypernculei is to study the light hypernuclei with few-body approach,such as ab initio calculations of (?)H,(?)H and (?)He or using the microscopic cluster model describe the light p-shell hypernuclei like (?)Be and 13?C.All these calculations request reliable theoretical few-body method.What we use in this thesis is one of the variational methods with fully rearrangement Jacobian coordinates named Gaussian expansion method(GEM).It constructs the trivial wave function with sets of Gaussian type wave function with coupled channel Jacobian coordinates.This is a high precision variational method which has made several high precision predictions of the experiment data.In chapter 2,we will explain this method in detail.Some extensions of this method are also given.New features may happen due to the participation of hyperon in the normal nuclei.One interesting feature is named'genuine hypernuclei'which arises from the Pauli principle.The Pauli exclusion principle among nucleons(proton or neutron)exclude some particular structures which will show up again if one nucleon is replaced with one hyperon(such as A).So in chapter 3,we try to the find the genuine structure inside the(?)Be based on the microscopic cluster model(?+?+?)with employing the Gaussian expansion method.Among the obtained stable states of (?)Be including two bound states and several resonant states,we find and prove the genuine structure and locate two (?)Be genuine states.However,compared to the old studies of (?)Be,some resonant states are'missing' and we have made our comments to this abnormal behavior.Moreover,we also find some 'new' resonances in high energy region which has never been proposed and we do some analysis to these states.The most important goal in hypernuclear physics is to investigate the hyperon-nucleon interaction such as ?N interaction.And one big difference in AN interaction is the mixing of the E component.For this purpose,in chapter 4,we study the (?)Li with microscopic ?+N+N+? and ?+N+N+? coupled channel cluster model.This is the first study of the E component in p-shell ? hypernuclei.With precise four body calculation using GEM,we obtain the spectra of (?)Li(T=0).Slightly inconsistence shows up in comparing with the experimental data.We calculate the E probabilities and find out it is rather small(?1%)which is consistent with the studies among the s-shell hypernuclei.We also find out the ?N-?N coupling tensor interaction is crucial to form the bound states of (?)Li(T=0).Finally we analysis the structure of (?)Li(T=0)bound states.The last chapter,5,we give a summation and outlook of our work.