Study On The Properties Of Mesons Within The ³P₀ Model And The Effective Lagrangian Approach

Hadron physics mainly focus on the hadron resonances and the interaction between them.In the last decades,a large number of experimental data on the resonances hadron have been accumulated experimentally,which provides a good platform for studying the properties of hadrons.Quantum chromodynamics(QCD)is the theory of describing strong interactions.Because of its properties of asymptotic freedom,it is difficult to study the properties of hadron resonances directly within QCD,and many phenomenological models are developed basing on the principle of QCD to investigate the hadron resonances.Firstly,we discuss the possibility of the Y(2175)state as the assignments of 23D1 and 33S1 s(?) meson,by calculating its strong decay width within the 3P0 model,considering the quark model predictions for the meson spectra.Our results show that the width of Y(2175)state as the assignments of 23D1s(?) state is consistent with the experimental measurement,which indicates that the possibility of the Y(2175)resonance as a normal s(?) meson state cannot be excluded.On the other hand,taking into account the measurements of Crystal Barrel collaboration,we have studied the process (?)p→ηη within the effective Lagrangian asproach.Beside the contributions of t-channel and u-channel N*(1535)exchanges,we also consider the mechanism of s-channel f0(2100)term.By fitting the experimental cross sections,we deduce some properties of f0(2100)state,such as the couplings.Although our model can well describe the total cross section,our results show that it is fail to describe the differential cross section,which indicates that more mechanisms should be taken into account in this process.