| The study of the properties of hadronic matter can provide us with important clues to understand the strong interaction.Mesons are the simplest hadronic state made up of a pair of positive and negative quarks.Studying the properties of mesons is essential for us to study more complex hadronic systems.In the past decades,various high energy physics experiments in the world have discovered very rich hadron states.Among them,e+e-annihilation experiment is an ideal platform to study vector meson states.A large amount of experimental data about vector meson states have been accumulated on the e+e-annihilation experiment,which provides us with a very good opportunity to study vector meson states.Therefore,vector mesons can be used as a breakthrough in the study of meson states to help us understand the interaction law of positive and negative quarks in mesons,so as to help us understand the nature of strong interaction.The first topic of this thesis,i.e.,construct the higher p mesonic states.Recently,the BESⅢ collaboration released the measurements of the e+e-→ωπ0,e+e-→η’π+π-and e+e-→f1(1285)π+π-reactions,all of which are ideal processes to study the isovector ρmeson family.In this work,we perform a analysis of the cross section data for the above three processes with the theoretical support on mass spectrum,and production and strong decay behaviors of the p meson family around 2.0 GeV.we identify the enhancement structure near 2034 MeV observed in e+e-→ωπ0 to be the interference contribution from two resonances ρ(1900)and ρ(2150),and another enhancement structure at 2111 MeV reported in e+e-→ρη’ to be the contributions from p(2000)and p(2150).Additionally,the observed broad resonance structure in e+e-→f1(1285)π+π-containing two substructures is suggested by the present work,and we also indicate a possible signal of ρ(5S)around 2.5 GeV in this process.Our study provide a new interpretation for the resonance structures observed in the above three processes,which is great significance for the construction of ρmesonic states near and above 2 GeV.Next,focusing on the observations of two enhancement structures around 2.2 GeV existing in e+e-→ωη and e+e-→ωπ0π0 at BESⅢ,we analyze how the ω(4S)andω(3D)states play the role in the e+e-→ωη and e+e-→ωπ0π0 processes.The present study is supported by theoretical ω mesonic spectroscopy.For reproducing the data of the cross sections of e+e-→ωη and ωπ0π0,the intermediate ω(4S)and ω(3D)should be introduced,which indicates that the enhancement structures around 2.2 GeV existing in e+e-→ωη and ωπ0π0 contain the ω(4S)and ω(3D)signals.Nonetheless,in the process e+e-ωη,the ω(4S)plays a dominant role,while the ω(4S)and ω(3D)have similar sizable contributions in the process of e+e-→ωπ0π0,which leads to a difference in the line shape of enhancement structure in the cross sections under the interference effect.Thus,we find a solution to alleviate the puzzling difference of resonance parameter of two reported enhancement structures around 2.2 GeV existing in e+e-→ωη and e+e-→ωπ0π0 at BESⅢ.The present study provides valuable information to construct ω meson family,which can be accessible at future experiment like BESⅢ.Finally,within the effective Lagrangian approach,we study the pp→ψη[ψ≡ψ(3686),J/ψ]reaction at the low energy where the contributions from nucleon pole and low-lying nucleon resonances,N(1520),N(1535)and N(1650)are considered.All the model parameters are determined with the help of current experimental data on the decay ofψ→ppη.Within the model parameters,the total and differential cross sections of the pp→ψη reaction are predicted.We show that the relative phases between different amplitudes of different nucleon resonance will change significantly the angular distributions of the pp→ψη reaction.Our work will provide important theoretical reference for charmonium research in future PANDA experiment. |
