In this paper,we study the ρ-meson electromagnetic form factors(EMFFs)within the framework of the light-front quark model.The physical form factors G_(C,M,Q)(Q^(2))of the ρ-meson,as well as the charged square radius...In this paper,we study the ρ-meson electromagnetic form factors(EMFFs)within the framework of the light-front quark model.The physical form factors G_(C,M,Q)(Q^(2))of the ρ-meson,as well as the charged square radius<r^(2)>,the magnetic moment μ,and the quadrupole moment Q,are calculated,which describe the behaviors of EMFFs at zero momentum transfer.Using the type-Ⅱ replacement,we find that the zero-mode does contribute zero to the matrix element S_(00)^(+).It is found that the“M→M_(0)”replacement improves the angular condition remarkably,which permits different prescriptions of ρ-meson EMFFs to give the consistent results.The residual tiny violation of angular condition needs other explanations beyond the zero-mode contributions.Our results indicate that the relativistic effects or interaction internal structure are weaken in the zero-binding limit.This work is also applicable to other spin-1 particles.展开更多
The ratio between the anomalous magnetic moments of proton and neutron has recently been suggested to be connected to the ratio of proton momentum fractions carried by the valence quarks inside it. This moment fractio...The ratio between the anomalous magnetic moments of proton and neutron has recently been suggested to be connected to the ratio of proton momentum fractions carried by the valence quarks inside it. This moment fraction ratio is respectively evaluated by using constituent quark model and chiral quark model in order to check meson cloud effect. Our results show that the meson cloud effect is remarkable to the ratio of the proton momentum fractions, and therefore, this ratiois a sensitive test for the meson cloud effect as well as for the SU(6) symmetry breaking effect.展开更多
Abstract The possibility of QQqq heavy-light four-quark bound states has been analyzed by means of the chiral SU（3） quark model, where Q is the heavy quark （c or b） and q is the light quark （u, d, or s）. We obt...Abstract The possibility of QQqq heavy-light four-quark bound states has been analyzed by means of the chiral SU（3） quark model, where Q is the heavy quark （c or b） and q is the light quark （u, d, or s）. We obtain a bound state for the bbnn configuration with quantum number JR=1^＋, I = 0 and for the ccnn （JR=1^＋, I=O） configuration, which is not bound but slightly above the D^＊ D^＊ threshold （n is u or d quark）. Meanwhile, we also conclude that a weakly bound state in bbnn system can also be found without considering the ehiral quark interactions between the two light quarks, yet its binding energy is weaker than that with the chiral quark interactions.展开更多
Using the phenomenological relativistic harmonic model （RHM） for quarks, we have obtained the masses of S wave charmonium states. The full Hamiltonian used in the investigation has Lorentz scalar plus vector confine...Using the phenomenological relativistic harmonic model （RHM） for quarks, we have obtained the masses of S wave charmonium states. The full Hamiltonian used in the investigation has Lorentz scalar plus vector confinement potential, along with the confined one gluon exchange potential （COGEP）. A good agreement with the experimental masses for the ground state and the radially excited states is obtained for both the triplet and singlet S wave mesons. The calculated charge radii, meson decay constants, leptonic decay width, two photon decay width, and the radiative M1 decay width are in good agreement with the experimental results.展开更多
The analytical forms of the interaction potentials between one pseudo-scalar/vector and one scalar/tensor/axial-vector heavy mesons are deduced based on a chiral quark model. Our results explicitly show the attractive...The analytical forms of the interaction potentials between one pseudo-scalar/vector and one scalar/tensor/axial-vector heavy mesons are deduced based on a chiral quark model. Our results explicitly show the attractive property between the two heavy mesons. Consequently, a series of possible molecular states are obtained. It is expected that our study might shed some light on the popular discussions of the newly observed XYZ states.展开更多
The new members of the charm-strange family Dsj^＊（2317）, Dsj（2460）, and Ds（2632）, which have the surprising properties, are challenging the present models. Many theoretical interpretations have been devoted to ...The new members of the charm-strange family Dsj^＊（2317）, Dsj（2460）, and Ds（2632）, which have the surprising properties, are challenging the present models. Many theoretical interpretations have been devoted to this issue. Most authors suggest that they are not the conventional cs^- quark model states, but possibly are four-quark states, molecule states, or mixtures of a P-wave cs^- and a four-quark state. In this work, we follow the four-quark-state picture, and study the masses of cnn^-s^-/css^-s^- states （n is u or d quark） in the chiral SU（3） quark model. The numerical results show that the mass of the mixed four-quark state （cnn^-s^-/css^-s^-） with spin parity j^P ： 0^＋ might not be Ds （2632）. At the same time, we also conclude that Dsj^＊（2317） and Dsj（2460） cannot be explained as the pure four-quark state.展开更多
Purpose: The Harmonic Neutron Hypothesis, HNH, has demonstrated that many of the fundamental physical constants, including the quarks, are associated with partial harmonic fractional exponents, , of a fundamental freq...Purpose: The Harmonic Neutron Hypothesis, HNH, has demonstrated that many of the fundamental physical constants, including the quarks, are associated with partial harmonic fractional exponents, , of a fundamental frequency, v<sub>F</sub>. The model has shown that the properties of the quarks are based on a progression of prime number composites. They also fall on three separate power law lines related to integer factors of the Y-intercept, , of a fundamental electromagnetic line which is scaled by the Rydberg constant, R and Planck’s constant. The quark lines are scaled by the quantum number factors {1, 2, 3}, and their Y-intercepts are referred to as n<sub>bem</sub>. The goal is to present a new proto-quark model in a six-quark inverted triangular array that defines the global organization of the valence quarks, which determines the hadronic quantum numbers, the standard hadron quark model, and the Cabibbo-Kobayashi-Maskawa (CKM) matrix. Methods: The charm, bottom, top quarks are associated with power law line Y-intercept, n<sub>bem</sub> equal to 1;the strange and down quarks with n<sub>bem</sub> equal to 2;and the up quark with n<sub>bem</sub> equal to 3. An inverted equilateral triangular array with three rows arranged from upper row (triangle base) to bottom row (triangle vertex), is associated respectively with n<sub>bem</sub> numbers 1, 2, and 3. The novelty of our perspective thus defines a new global valence quark organization which supersedes the Standard hadron composite quark model. The quarks are ordered via relative mass, partial fractions, and n<sub>bem</sub> quantum number. The top row of our inverted triangle includes the c, b, and t quarks from left to right;the middle row depicts the d and s quarks;and the bottom row, the up quark. Results: Our array depicts a quantum generator of the global organization of the valence quarks defining the composite quark model. The vertices of the triangular array are the up quarks, the midpoints are the down quarks. All weak transitions are from a corner to a midpoint or vice versa. The standard 3 by 3 CKM matrix is generated from the new quark triangle with each up type quark (u, c, and t) transforming to each down type (d, s, and b), with their experimental flavor transition magnitudes given. Conclusion: A new quark quantum number, n<sub>bem</sub>, is an important discovery that generates a new proto-valence quark triangle that secondarily generates the composite quark model and the CKM matrix.展开更多
The color-flavor locked(CFL) strangelets have been investigated in a new quark model with linear confinement and one-gluon-exchange interactions.Considering Coulomb energy,we have studied the properties of three kinds...The color-flavor locked(CFL) strangelets have been investigated in a new quark model with linear confinement and one-gluon-exchange interactions.Considering Coulomb energy,we have studied the properties of three kinds of CFL strangelets,namely,positively charged,negatively charged and nearly neutral CFL strangelets.It is found that the one-gluon-exchange effect lowers the energy of a strangelet considerably and thus makes it much more stable than without considering the effect.The charge of a positive strangelet is larger than 0.15A 2/3 with A being the baryon number,but smaller than that in bag model.The charge of a negatively charged or nearly neutral CFL strangelet is nearly proportional to A 1/3.展开更多
Using the Thomas-Fermi quark model,a collective,spherically symmetric density of states is created to represent a gas of interacting fermions with various degeneracies at zero temperature.Over a family of pentaquarks,...Using the Thomas-Fermi quark model,a collective,spherically symmetric density of states is created to represent a gas of interacting fermions with various degeneracies at zero temperature.Over a family of pentaquarks,uudcc,color interaction probabilities were obtained after averaging over all the possible configurations.Three different functions are developed for light,charm,and anti-charm quarks and are assumed to be linearly related by some proportionality constants.Interesting patterns of quark distributions are observed while analyzing the quark function consistency conditions for such constants.展开更多
The structures of Ωω states with spin-parity JP= 5/2^-, 3/2^-, and 1/2^- are dynamically studied in both the chlral SU（3） quark model and the extended chiral SU（3） quark model by solving a resonating group meth...The structures of Ωω states with spin-parity JP= 5/2^-, 3/2^-, and 1/2^- are dynamically studied in both the chlral SU（3） quark model and the extended chiral SU（3） quark model by solving a resonating group method （RGM） equation. The model parameters are taken from our previous work, which gave a satisfactory description of the energies of the baryon ground states, the binding energy of the deuteron, the nucleon-nucleon （NN） scattering phase shifts, and the hyperon-nucleon （YN） cross sections. The calculated results show that the Ωω state has an attractive interaction, and in the extended chiral SU（3） quark model such attraction can make for a Ωω quasi-bound state with spin-parity JP = 3/2^- or 5/2^- and the binding energy of about several MeV.展开更多
We study the nucleon form factors and the nucleon-△（1232） transitions in a framework of hypercentral constituent quark model. The pion meson cloud effect is taken into account explicitly. Our results show that the ...We study the nucleon form factors and the nucleon-△（1232） transitions in a framework of hypercentral constituent quark model. The pion meson cloud effect is taken into account explicitly. Our results show that the pion cloud contributes substantially to the nucleon form factors as well as to the helicity amplitudes of △（1232）, and it gives an improved agreement compared to the experimental.展开更多
The low-energy region kaon-pion S- and P-wave phase shifts with isospin I = 1/2 and I = 3/2 are dynamically studied in the chiral SU(3) quark model by solving a resonating group method equation. The model parameters a...The low-energy region kaon-pion S- and P-wave phase shifts with isospin I = 1/2 and I = 3/2 are dynamically studied in the chiral SU(3) quark model by solving a resonating group method equation. The model parameters are taken to be the values fitted by the energies of the baryon ground states and the kaon-nucleon elastic scattering phase shifts of different partial waves. As a preliminary study the s-channel q(-q) annihilation interactions are not included since they only act in the very short range and are subsequently assumed to be unimportant in the low-energy domain. The numerical results are in qualitative agreement with the experimental data.展开更多
Using relativistic spin-flavor wave functions of a Lorentz-covariant light cone quark model, we calculate the electromagnetic form factors of two S11 resonances, N（1535） and N（1650）, and the helicity amplitudes A1...Using relativistic spin-flavor wave functions of a Lorentz-covariant light cone quark model, we calculate the electromagnetic form factors of two S11 resonances, N（1535） and N（1650）, and the helicity amplitudes A1/2 and S1/2 for electroexcitation of the S11 resonances from the nucleon. The electromagnetic form factors of these S11 resonances are found to be similar to those of the nucleon in shape, while the charge form factor of neutral N（1650） is nearly zero. The relative peak height of the S11 charge form factors is controlled by the mixing angle common to both resonance wave functions. As in most quark models, there is a systematic overestimate of A1/2 in both N（1535） and N（1650） cases at the photon point. A sizeable S1/2 for all cases is produced as suggested by experiments.展开更多
We study the ＇t Hooft coupling gt and the mass splitting of the ground-state baryons in terms of the large Noinspired quark model, by which the Hartree wavefunctions of light quarks are obtained. By fitting the spect...We study the ＇t Hooft coupling gt and the mass splitting of the ground-state baryons in terms of the large Noinspired quark model, by which the Hartree wavefunctions of light quarks are obtained. By fitting the spectra of decuplet and octet baryons, we obtain the ＇t Hooft coupling gt to be around 1.57. We generalize the scenario to the case of heavy baryons, such as Ac, gt values which does not deviate much from 1.57, as well as to the case of mesons with 9t far from that for baryons. The consequence is discussed.展开更多
The electromagnetic transition between the nucleon and excited baryons has long been recognized as an important source of information for understanding strong interactions in the domain of quark confinement. We study ...The electromagnetic transition between the nucleon and excited baryons has long been recognized as an important source of information for understanding strong interactions in the domain of quark confinement. We study the electromagnetic properties of the excitation of the negative parity the N~*(1535) resonances in the nonrelativistic constituent quark model at large momentum transfers and have performed a calculation the longitudinal and transverse helicity amplitudes. Since the helicity amplitudes depend strongly on the quark wave function in this paper, we consider the baryon as a simple, non-relativistically three-body quark model and also consider a hypercentral potential scheme for the internal baryon structure, which makes three-body forces among three quarks. Since the hyper central potential depends only on the hyper radius, therefore, the Cornell potential which is a combination of the Coulombic-like term plus a linear confining term is considered as the potential for interaction between quarks. In our work, in solving the Schrodinger equation with the Cornell potential, the Nikiforov–Uvarov method employed, and the analytic eigen-energies and eigen-functions obtained. By using the obtained eigen-functions, the transition amplitudes calculated. We show that our results in the range Q^2> 2GeV^2 lead to an overall better agreement with the experimental data in comparison with the other three non-relativistic quark models.展开更多
The N-N <sup>1</sup>S<sub>0</sub> scattering length differences Δα<sub>CSB</sub> and Δα<sub>CIH</sub> of the charge symmetrybreaking and charge independence breaking...The N-N <sup>1</sup>S<sub>0</sub> scattering length differences Δα<sub>CSB</sub> and Δα<sub>CIH</sub> of the charge symmetrybreaking and charge independence breaking are calculated by a resonating group method with aquark cluster model.By adding the QED-QCD interference effect to the quark mass differenceand the electromagnetic interaction,the Δα<sub>CSH</sub> and Δα<sub>CIH</sub> can be reproduced with modelparameters constrained by the hadron isomultiplet masses.展开更多
Since the discovery of T_(cc)by LHCb,there has been considerable interest in T_(cc)and its heavy-flavor partners.However,the study of its strange partner T_(ss)has been largely overlooked.Within the framework of the c...Since the discovery of T_(cc)by LHCb,there has been considerable interest in T_(cc)and its heavy-flavor partners.However,the study of its strange partner T_(ss)has been largely overlooked.Within the framework of the chiral quark model,we conducted a systematic study of the bound states of T_(ss)based on the Gaussian Expansion Method.We considered all physical channels with 01^(+),including molecular and diquark structures.Moreover,by considering the coupling between diquarks and molecular states,our calculations allowed us to identify a deep bound state with a bounding energy of 60 MeV primarily composed of KK^(*).Using the^(3)P_(0)model,we calculated the decay width of K^(*)within the KK^(*)bound state,which is approximated as the decay width of the bound state in the T_(ss)system.These results indicate that,owing to the effect of binding energy,the decay width of K^(*)in KK^(*)is approximately 3 MeV smaller than that of K^(*)in vacuum.Additionally,resonance state calculations were performed.We used the real-scaling method to search for possible resonance states in the T_(ss)sysytem.Because of the strong attraction in the[K^(*)]_(8)[K^(*)]_(8)configuration,four resonance states were found in the vicinity of 2.2-2.8 GeV,predominantly featuring hidden-color structures.The decay widths of these states are less than 10 MeV.We strongly recommend experimental efforts to search for the resonance states in the T_(ss)system predicted by our calculations.展开更多
We investigated the ground state(1S),radially excited states(2S)and(3S),and orbitally excited state(1P)for the heavy charmonia(cc)and bottomonia(bb)mesons in the light-front quark model(LFQM).The light-front wave func...We investigated the ground state(1S),radially excited states(2S)and(3S),and orbitally excited state(1P)for the heavy charmonia(cc)and bottomonia(bb)mesons in the light-front quark model(LFQM).The light-front wave functions have been successful in explaining various physical properties of meson states in the past,especially for the 1S and 2S states.However,the radially excited state 3S and orbitally excited state 1P have rarely been investigated.In this study,we considered these two excited states and investigated the electromagnetic form factors(EMFFs),charge radii,decay constants,parton distribution functions(PDFs),and the distribution amplitudes(DAs)for the quarkonia system.For the sake of completeness,we also studied the ground and the first excited states of quarkonia mesons.We also illustrated the 3D wave functions for the radially excited states to study their nodal structures.展开更多
Radiative decays D((s))*→D((s))γare revisited in light of new experimental data from the BaBar and BESⅢCollaborations.The radiative couplings gD*Dγencoding nonperturbative QCD effects are calculated in the framewo...Radiative decays D((s))*→D((s))γare revisited in light of new experimental data from the BaBar and BESⅢCollaborations.The radiative couplings gD*Dγencoding nonperturbative QCD effects are calculated in the framework of the covariant confined quark model developed by us.We compare our results with other theoretical studies and experimental data.The couplings(in GeV-1)|g(D*+D+γ)|=0.45(9)and|g(D*0D0γ)|=1.72(34)calculated in our model agree with the corresponding experimental data|g(D*+D+γ)|=0.47(7)and|g(D*0D0γ)|=1.77(16).The most interesting case is the decay Ds*→Dsγ,for which a recent prediction based on light-cone sum rules at next-to-leading order|gDs*Dsγ|=0.60(19)deviates from the first(and only to date)lattice QCD result|gDs*Dsγ|=0.11(2)at nearly3σ.Our calculation yields|gDs*Dsγ|=0.29(6),which falls somehow between the two mentioned results,although it is larger than those predicted in other studies using quark models or QCD sum rules.展开更多
The unquenched quark model for the light quarkonium and charmonium states is explored in this study.The quark-pair creation operator in the^(3)P_(0) model,which combines the two-quark and four-quark components,is modi...The unquenched quark model for the light quarkonium and charmonium states is explored in this study.The quark-pair creation operator in the^(3)P_(0) model,which combines the two-quark and four-quark components,is modified by considering the effects of the created quark pair's energy.Furthermore,the separation between the created quark pair and valence quark pair is modified.All the wave functions,including those for the mesons and the relative motion between two mesons,are obtained by solving the corresponding Schrodinger equation using the Gaussian expansion method.The aim of this study is to find a new set of parameters that can accurately describe the mass spectrum of low-lying light quarkonium and charmonium states.Moreover,certain exotic states,such as X(3872),can be described well in the unquenched quark model.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11875122,12175025,and 12147102)Tongling University Talent Program(Grant No.R23100)。
文摘In this paper,we study the ρ-meson electromagnetic form factors(EMFFs)within the framework of the light-front quark model.The physical form factors G_(C,M,Q)(Q^(2))of the ρ-meson,as well as the charged square radius<r^(2)>,the magnetic moment μ,and the quadrupole moment Q,are calculated,which describe the behaviors of EMFFs at zero momentum transfer.Using the type-Ⅱ replacement,we find that the zero-mode does contribute zero to the matrix element S_(00)^(+).It is found that the“M→M_(0)”replacement improves the angular condition remarkably,which permits different prescriptions of ρ-meson EMFFs to give the consistent results.The residual tiny violation of angular condition needs other explanations beyond the zero-mode contributions.Our results indicate that the relativistic effects or interaction internal structure are weaken in the zero-binding limit.This work is also applicable to other spin-1 particles.
文摘The ratio between the anomalous magnetic moments of proton and neutron has recently been suggested to be connected to the ratio of proton momentum fractions carried by the valence quarks inside it. This moment fraction ratio is respectively evaluated by using constituent quark model and chiral quark model in order to check meson cloud effect. Our results show that the meson cloud effect is remarkable to the ratio of the proton momentum fractions, and therefore, this ratiois a sensitive test for the meson cloud effect as well as for the SU(6) symmetry breaking effect.
基金supported in part by the National Natural Science Foundation of China under Grant Nos.10475087 and 10775146
文摘Abstract The possibility of QQqq heavy-light four-quark bound states has been analyzed by means of the chiral SU（3） quark model, where Q is the heavy quark （c or b） and q is the light quark （u, d, or s）. We obtain a bound state for the bbnn configuration with quantum number JR=1^＋, I = 0 and for the ccnn （JR=1^＋, I=O） configuration, which is not bound but slightly above the D^＊ D^＊ threshold （n is u or d quark）. Meanwhile, we also conclude that a weakly bound state in bbnn system can also be found without considering the ehiral quark interactions between the two light quarks, yet its binding energy is weaker than that with the chiral quark interactions.
基金the BRNS for funding the project(Sanction No.2010/37P/18/BRNS)
文摘Using the phenomenological relativistic harmonic model （RHM） for quarks, we have obtained the masses of S wave charmonium states. The full Hamiltonian used in the investigation has Lorentz scalar plus vector confinement potential, along with the confined one gluon exchange potential （COGEP）. A good agreement with the experimental masses for the ground state and the radially excited states is obtained for both the triplet and singlet S wave mesons. The calculated charge radii, meson decay constants, leptonic decay width, two photon decay width, and the radiative M1 decay width are in good agreement with the experimental results.
基金Supported by National Natural Science Foundation of China under Grant Nos.11105158,11035006,10975146,11261130,and 11475192Ministry of Science and Technology of China under Grant No.2009CB825200+1 种基金the Fundamental Research Funds for the Central Universities of Chinathe DFG and NSFC through Funds Provides to the Sino–German CRC 110"Symmetries and the Emergence of Structure in QCD"
文摘The analytical forms of the interaction potentials between one pseudo-scalar/vector and one scalar/tensor/axial-vector heavy mesons are deduced based on a chiral quark model. Our results explicitly show the attractive property between the two heavy mesons. Consequently, a series of possible molecular states are obtained. It is expected that our study might shed some light on the popular discussions of the newly observed XYZ states.
基金National Natural Science Foundation of China under Grant No 10475087
文摘The new members of the charm-strange family Dsj^＊（2317）, Dsj（2460）, and Ds（2632）, which have the surprising properties, are challenging the present models. Many theoretical interpretations have been devoted to this issue. Most authors suggest that they are not the conventional cs^- quark model states, but possibly are four-quark states, molecule states, or mixtures of a P-wave cs^- and a four-quark state. In this work, we follow the four-quark-state picture, and study the masses of cnn^-s^-/css^-s^- states （n is u or d quark） in the chiral SU（3） quark model. The numerical results show that the mass of the mixed four-quark state （cnn^-s^-/css^-s^-） with spin parity j^P ： 0^＋ might not be Ds （2632）. At the same time, we also conclude that Dsj^＊（2317） and Dsj（2460） cannot be explained as the pure four-quark state.
文摘Purpose: The Harmonic Neutron Hypothesis, HNH, has demonstrated that many of the fundamental physical constants, including the quarks, are associated with partial harmonic fractional exponents, , of a fundamental frequency, v<sub>F</sub>. The model has shown that the properties of the quarks are based on a progression of prime number composites. They also fall on three separate power law lines related to integer factors of the Y-intercept, , of a fundamental electromagnetic line which is scaled by the Rydberg constant, R and Planck’s constant. The quark lines are scaled by the quantum number factors {1, 2, 3}, and their Y-intercepts are referred to as n<sub>bem</sub>. The goal is to present a new proto-quark model in a six-quark inverted triangular array that defines the global organization of the valence quarks, which determines the hadronic quantum numbers, the standard hadron quark model, and the Cabibbo-Kobayashi-Maskawa (CKM) matrix. Methods: The charm, bottom, top quarks are associated with power law line Y-intercept, n<sub>bem</sub> equal to 1;the strange and down quarks with n<sub>bem</sub> equal to 2;and the up quark with n<sub>bem</sub> equal to 3. An inverted equilateral triangular array with three rows arranged from upper row (triangle base) to bottom row (triangle vertex), is associated respectively with n<sub>bem</sub> numbers 1, 2, and 3. The novelty of our perspective thus defines a new global valence quark organization which supersedes the Standard hadron composite quark model. The quarks are ordered via relative mass, partial fractions, and n<sub>bem</sub> quantum number. The top row of our inverted triangle includes the c, b, and t quarks from left to right;the middle row depicts the d and s quarks;and the bottom row, the up quark. Results: Our array depicts a quantum generator of the global organization of the valence quarks defining the composite quark model. The vertices of the triangular array are the up quarks, the midpoints are the down quarks. All weak transitions are from a corner to a midpoint or vice versa. The standard 3 by 3 CKM matrix is generated from the new quark triangle with each up type quark (u, c, and t) transforming to each down type (d, s, and b), with their experimental flavor transition magnitudes given. Conclusion: A new quark quantum number, n<sub>bem</sub>, is an important discovery that generates a new proto-valence quark triangle that secondarily generates the composite quark model and the CKM matrix.
基金Supported by National Natural Science Foundation of China under Grant Nos. 11045006,11135011the Chinese Academy of Sciences Key Project Y12A0A0012
文摘The color-flavor locked(CFL) strangelets have been investigated in a new quark model with linear confinement and one-gluon-exchange interactions.Considering Coulomb energy,we have studied the properties of three kinds of CFL strangelets,namely,positively charged,negatively charged and nearly neutral CFL strangelets.It is found that the one-gluon-exchange effect lowers the energy of a strangelet considerably and thus makes it much more stable than without considering the effect.The charge of a positive strangelet is larger than 0.15A 2/3 with A being the baryon number,but smaller than that in bag model.The charge of a negatively charged or nearly neutral CFL strangelet is nearly proportional to A 1/3.
文摘Using the Thomas-Fermi quark model,a collective,spherically symmetric density of states is created to represent a gas of interacting fermions with various degeneracies at zero temperature.Over a family of pentaquarks,uudcc,color interaction probabilities were obtained after averaging over all the possible configurations.Three different functions are developed for light,charm,and anti-charm quarks and are assumed to be linearly related by some proportionality constants.Interesting patterns of quark distributions are observed while analyzing the quark function consistency conditions for such constants.
基金The project supported in part by National Natural Science Foundation of China under Grant No. 10475087
文摘The structures of Ωω states with spin-parity JP= 5/2^-, 3/2^-, and 1/2^- are dynamically studied in both the chlral SU（3） quark model and the extended chiral SU（3） quark model by solving a resonating group method （RGM） equation. The model parameters are taken from our previous work, which gave a satisfactory description of the energies of the baryon ground states, the binding energy of the deuteron, the nucleon-nucleon （NN） scattering phase shifts, and the hyperon-nucleon （YN） cross sections. The calculated results show that the Ωω state has an attractive interaction, and in the extended chiral SU（3） quark model such attraction can make for a Ωω quasi-bound state with spin-parity JP = 3/2^- or 5/2^- and the binding energy of about several MeV.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 10475088 and 90103020, the CAS Knowledge Innovation Project under Grant No. KC2-SW-N02, and the Institute of Theoretical Physics The support from the Center of Theoretical Nuclear Physics, Lanzhou National Laboratory of Heavy Ion Accelerator is appreciated. 0ne of authors （Y.B. Dong） thanks the Department of Physics, Genova University for the hospitality. Authors are grateful to the discussions with M.M. Giannini and Santopinto.
文摘We study the nucleon form factors and the nucleon-△（1232） transitions in a framework of hypercentral constituent quark model. The pion meson cloud effect is taken into account explicitly. Our results show that the pion cloud contributes substantially to the nucleon form factors as well as to the helicity amplitudes of △（1232）, and it gives an improved agreement compared to the experimental.
文摘The low-energy region kaon-pion S- and P-wave phase shifts with isospin I = 1/2 and I = 3/2 are dynamically studied in the chiral SU(3) quark model by solving a resonating group method equation. The model parameters are taken to be the values fitted by the energies of the baryon ground states and the kaon-nucleon elastic scattering phase shifts of different partial waves. As a preliminary study the s-channel q(-q) annihilation interactions are not included since they only act in the very short range and are subsequently assumed to be unimportant in the low-energy domain. The numerical results are in qualitative agreement with the experimental data.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 10075056 and 90103020 and the CAS Knowledge Innovation Project under Grant No. KC2-SW-N02.
文摘Using relativistic spin-flavor wave functions of a Lorentz-covariant light cone quark model, we calculate the electromagnetic form factors of two S11 resonances, N（1535） and N（1650）, and the helicity amplitudes A1/2 and S1/2 for electroexcitation of the S11 resonances from the nucleon. The electromagnetic form factors of these S11 resonances are found to be similar to those of the nucleon in shape, while the charge form factor of neutral N（1650） is nearly zero. The relative peak height of the S11 charge form factors is controlled by the mixing angle common to both resonance wave functions. As in most quark models, there is a systematic overestimate of A1/2 in both N（1535） and N（1650） cases at the photon point. A sizeable S1/2 for all cases is produced as suggested by experiments.
基金Supported by the National Natural Science Foundation of China under Grant No 11265014
文摘We study the ＇t Hooft coupling gt and the mass splitting of the ground-state baryons in terms of the large Noinspired quark model, by which the Hartree wavefunctions of light quarks are obtained. By fitting the spectra of decuplet and octet baryons, we obtain the ＇t Hooft coupling gt to be around 1.57. We generalize the scenario to the case of heavy baryons, such as Ac, gt values which does not deviate much from 1.57, as well as to the case of mesons with 9t far from that for baryons. The consequence is discussed.
文摘The electromagnetic transition between the nucleon and excited baryons has long been recognized as an important source of information for understanding strong interactions in the domain of quark confinement. We study the electromagnetic properties of the excitation of the negative parity the N~*(1535) resonances in the nonrelativistic constituent quark model at large momentum transfers and have performed a calculation the longitudinal and transverse helicity amplitudes. Since the helicity amplitudes depend strongly on the quark wave function in this paper, we consider the baryon as a simple, non-relativistically three-body quark model and also consider a hypercentral potential scheme for the internal baryon structure, which makes three-body forces among three quarks. Since the hyper central potential depends only on the hyper radius, therefore, the Cornell potential which is a combination of the Coulombic-like term plus a linear confining term is considered as the potential for interaction between quarks. In our work, in solving the Schrodinger equation with the Cornell potential, the Nikiforov–Uvarov method employed, and the analytic eigen-energies and eigen-functions obtained. By using the obtained eigen-functions, the transition amplitudes calculated. We show that our results in the range Q^2> 2GeV^2 lead to an overall better agreement with the experimental data in comparison with the other three non-relativistic quark models.
基金The project supported by the NSF(19675018)SEDC of ChinaSSTC of China
文摘The N-N <sup>1</sup>S<sub>0</sub> scattering length differences Δα<sub>CSB</sub> and Δα<sub>CIH</sub> of the charge symmetrybreaking and charge independence breaking are calculated by a resonating group method with aquark cluster model.By adding the QED-QCD interference effect to the quark mass differenceand the electromagnetic interaction,the Δα<sub>CSH</sub> and Δα<sub>CIH</sub> can be reproduced with modelparameters constrained by the hadron isomultiplet masses.
基金Supported partly by the National Natural Science Foundation of China(12205249)the Funding for School-Level Research Projects of Yancheng Institute of Technology(xjr2022039,xjr2022040,xjr2020038)。
文摘Since the discovery of T_(cc)by LHCb,there has been considerable interest in T_(cc)and its heavy-flavor partners.However,the study of its strange partner T_(ss)has been largely overlooked.Within the framework of the chiral quark model,we conducted a systematic study of the bound states of T_(ss)based on the Gaussian Expansion Method.We considered all physical channels with 01^(+),including molecular and diquark structures.Moreover,by considering the coupling between diquarks and molecular states,our calculations allowed us to identify a deep bound state with a bounding energy of 60 MeV primarily composed of KK^(*).Using the^(3)P_(0)model,we calculated the decay width of K^(*)within the KK^(*)bound state,which is approximated as the decay width of the bound state in the T_(ss)system.These results indicate that,owing to the effect of binding energy,the decay width of K^(*)in KK^(*)is approximately 3 MeV smaller than that of K^(*)in vacuum.Additionally,resonance state calculations were performed.We used the real-scaling method to search for possible resonance states in the T_(ss)sysytem.Because of the strong attraction in the[K^(*)]_(8)[K^(*)]_(8)configuration,four resonance states were found in the vicinity of 2.2-2.8 GeV,predominantly featuring hidden-color structures.The decay widths of these states are less than 10 MeV.We strongly recommend experimental efforts to search for the resonance states in the T_(ss)system predicted by our calculations.
基金Narinder Kumar and Harleen Dahiya would like to acknowledge the research grant received from the Science and Engineering Research Board,Government of India under Teachers Associateship Research Excellence Award(TAR/2021/000157)。
文摘We investigated the ground state(1S),radially excited states(2S)and(3S),and orbitally excited state(1P)for the heavy charmonia(cc)and bottomonia(bb)mesons in the light-front quark model(LFQM).The light-front wave functions have been successful in explaining various physical properties of meson states in the past,especially for the 1S and 2S states.However,the radially excited state 3S and orbitally excited state 1P have rarely been investigated.In this study,we considered these two excited states and investigated the electromagnetic form factors(EMFFs),charge radii,decay constants,parton distribution functions(PDFs),and the distribution amplitudes(DAs)for the quarkonia system.For the sake of completeness,we also studied the ground and the first excited states of quarkonia mesons.We also illustrated the 3D wave functions for the radially excited states to study their nodal structures.
基金Supported by Ho Chi Minh City University of Technology and Education(T2022-26)。
文摘Radiative decays D((s))*→D((s))γare revisited in light of new experimental data from the BaBar and BESⅢCollaborations.The radiative couplings gD*Dγencoding nonperturbative QCD effects are calculated in the framework of the covariant confined quark model developed by us.We compare our results with other theoretical studies and experimental data.The couplings(in GeV-1)|g(D*+D+γ)|=0.45(9)and|g(D*0D0γ)|=1.72(34)calculated in our model agree with the corresponding experimental data|g(D*+D+γ)|=0.47(7)and|g(D*0D0γ)|=1.77(16).The most interesting case is the decay Ds*→Dsγ,for which a recent prediction based on light-cone sum rules at next-to-leading order|gDs*Dsγ|=0.60(19)deviates from the first(and only to date)lattice QCD result|gDs*Dsγ|=0.11(2)at nearly3σ.Our calculation yields|gDs*Dsγ|=0.29(6),which falls somehow between the two mentioned results,although it is larger than those predicted in other studies using quark models or QCD sum rules.
基金Supported by the National Natural Science Foundation of China(12205125,11847145,12205249,11865019)the Natural Science Foundation of Jiangsu Province,China(BK20221166)。
文摘The unquenched quark model for the light quarkonium and charmonium states is explored in this study.The quark-pair creation operator in the^(3)P_(0) model,which combines the two-quark and four-quark components,is modified by considering the effects of the created quark pair's energy.Furthermore,the separation between the created quark pair and valence quark pair is modified.All the wave functions,including those for the mesons and the relative motion between two mesons,are obtained by solving the corresponding Schrodinger equation using the Gaussian expansion method.The aim of this study is to find a new set of parameters that can accurately describe the mass spectrum of low-lying light quarkonium and charmonium states.Moreover,certain exotic states,such as X(3872),can be described well in the unquenched quark model.
