| In 2003,the charm state X(3872)was discovered by the high energy physics experi-mental collaboration Belle and confirmed by many other collaborations.This is the first exotic state measured in experiment,which aroused a great interest in the field of hadron physics.Since then,the major theoretical workers of particle physics have turned their attention to the study of strange hadron states.In the past ten years,with the continuous improvement of experimental technology,the major particle physics experimental groups have discovered many strange Hadron states,ie XYZ particles.For example:In 2005,the BaBar experimental group discovered Y(4260),the BESIII and Belle experimental group reported the primitive state in 2013 Zc(3900),and 2016 DO the experimental group dis-covered X(5568)etc.In response to these peculiar hadron states,people try to use various methods and models to study it.One of the theoretical methods that plays an important role is the quantum chromodynamics(QCD)theory,which starts from the first principle and describes.The strong interaction phenomenon in nature can solve the basic hadron property problem through perturbation theory in the high-energy region,but QCD is not applicable in the low-energy region.Because it has non-perturbation characteristics,it is difficult to directly study the physical phenomenon of hadrons.Methods such as lattice QCD,Dyson-Schwinger equations,effective field theory and QCD sum-rule have achieved good results when dealing with the properties of ground state hadrons.However,due to the complexity of the calculation and the characteristics of the method itself,these meth-ods encounter problems in studying the multi-quark states.The phenomenological quark model has always been an important non-perturbative method for studying low-energy hadron problems.It has achieved extraordinary achievements in the field of describing hadron spectrum,hadron-hadron interaction,and nucleon-nucleon scattering.It is even possible to predict new hadron states with the help of the quark model.On this basis,this article uses the phenomenological component quark model to expand the system from two quarks to four quark systems,trying to explain some of the strange states found in experiments.In the traditional quark model,there are two mesons and baryons.We use the chiral component quark model to fit the energy of the meson spectrum.The calculated results are very consistent with the experimental values.Therefore,we A set of experimental pa-rameters was obtained,which laid the foundation for the next four-quark system research For the wave function of the four-quark system,it has four degrees of freedom,namely orbit,spin,taste,and color.Among them,the wave function of the orbit part is expanded by the multi-Gaussian method,and the wave functions of the remaining three parts are constructed using group theory knowledgeIn 2003,when BarBar and CLEO collaborations were studying Ds+?0 invariant mass spectrum and analysis Ds*+?0,the Ds0*(2317)and Ds1(2460)states were found respectively These states have been widely concerned because of their narrow width and low mass Since their discovery,research on the quantum numbers,decay modes,decay width,etc of these two states has been ongoing.In addition to these two states,many collaborations have also found many similar charmed exotic states containing the cs meson,but so far,people have not fully understood their internal structure and have not reached a unified explanation.At present,there are mainly the following explanations:DK molecular state,traditional cs meson,cs meson and four quark mixed state,pseudoscalar Ds meson chiral partner state and so onIn this paper,we study the Ds0*(2317)and Ds1(2460)states in two pictures,traditional cs meson and four-quark states in the framework of quark model.For the p-wave excited states of cs meson,our calculations show that the masses of 0+and 1+states are very close to the experimental masses of Ds0*(2317)and Ds1(2460).So it is possible to explain these two states in qq picture.However the isospin violation decays of these two states are not flavor the explanation.Then we study the four-quark states containing c quark and s antiquark,and try to explain the structures of Ds0*(2317)and Ds1(2460)states.Based on the chiral quark model,we have studied cs four-quark system with one light quark and one light antiquark with quantum numbers of JP=0+,1+,2+,respectively,and consider the coupling of the color singlet and the hidden color channel.The calculation shows that the interaction between the two mesons in the color singlet is insufficient to bind the two mesons to form a molecule.For the hidden color channel,although the resonance states can be formed due to the color structure,the energy is too high to be used to explain the Ds0*(2317)and Ds1(2460)states found in experiments.In the calculation,in addition to the meson structure,we also considered the diquark-antidiquark structure,but the obtained lowest energies of the states are still much greater than 2317 MeV and 2460 MeV.Because Ds0*(2317)is lower than the threshold of DK state by 40 MeV,and our calculations show that there is no bound state in DK system.Therefore,our results prefer the interpretation that these two states are mixed states of two-quark cs and four-quark states.In addition,several resonance states are predicted,the lowest resonance energy is 2839 MeV with quantum numbers IJP=10+.The state with IJP=00+has the energy 2890.8 MeVIn the past decades of physical model research,the component quark model has played a role that cannot be ignored.However,with the deepening of research and the continuous advancement of experimental technology,various high-excited states of hadrons have been continuously discovered,and the existing model theory encountered difficulties in dealing with these states.Therefore,we need to continuously improve and perfect the quark model in order to better explain some of the new hadron states discovered in experiments,and thus deepen our understanding and understanding of hadron physics. |
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