The newly observed D^＊aj family containing D^＊aj（2317）, Daj（2460）, and Daj（2632） attracts great interests. Determining their structures may be an important task for both theorists and experimentalists. In this...The newly observed D^＊aj family containing D^＊aj（2317）, Daj（2460）, and Daj（2632） attracts great interests. Determining their structures may be an important task for both theorists and experimentalists. In this work we use a non-relativistic model （the harmonic oscillator model） to evaluate the production rate of D^＊aj （2317） from the decays of ψ（4415）. For a comparison, we a/so employ the widely adopted heavy quark effective theory to repeat the calculation. We lind that the rate is sizable and may be observed at BES III and CLEO, if it is a p-wave excited state of Da（1968）. Unfortunately, the other two members of the family cannot be observed through decays of charmonia, because of the constraints from the final state phase space.展开更多
In this paper, firstly, we investigate the neutrino emissivity from quark Urca process in strong magnetic field. Then, we discuss the heat capacity of strange stars in strong magnetic field. Finally, we give the cooli...In this paper, firstly, we investigate the neutrino emissivity from quark Urca process in strong magnetic field. Then, we discuss the heat capacity of strange stars in strong magnetic field. Finally, we give the cooling curve in strong magnetic field. In order to make a comparison, we also give the corresponding cooling curve in the case of null magnetic field. It turns out that strange stars cool faster in strong magnetic field than that without magnetic field.展开更多
With the diquark structure of ∧c, we investigate the branching ratio of ∧c→nπ^+ and pπ^0. The results show that without considering the finM state interaction (FSI), the branching ratio of ∧c→pπ^0 is only of o...With the diquark structure of ∧c, we investigate the branching ratio of ∧c→nπ^+ and pπ^0. The results show that without considering the finM state interaction (FSI), the branching ratio of ∧c→pπ^0 is only of order 10^-6 whereas this ratio could reach 10^-4 and is at the same order as ∧c→nπ^+ if taking into account the FSI effects. Concrete values depend on phenomenologicM parameters adopted in the calculations. These branching ratios can be measured in the experiments to come.展开更多
In this article, we study the pentaquark state Θ＋（1540） with a （scalar） diquark-（pseudoscalar） diquarkantiquark type interpolating current in the framework of the QCD sum rules approach by including the contri...In this article, we study the pentaquark state Θ＋（1540） with a （scalar） diquark-（pseudoscalar） diquarkantiquark type interpolating current in the framework of the QCD sum rules approach by including the contributions from the direct instantons. The numerical results indicate that the contributions from the direct instantons are very small and can be safely neglected.展开更多
Using the Dyson-Schwinger equation and perturbation theory, we calculate the mixed quark-gluon condensates in the chiral limit and in the case of nonzero quark current mass for the light quark u/d and strange quark s....Using the Dyson-Schwinger equation and perturbation theory, we calculate the mixed quark-gluon condensates in the chiral limit and in the case of nonzero quark current mass for the light quark u/d and strange quark s. The results show that the mixed quark-gluon condensate will decrease when the quark mass increases. For the quark with zero mass, we obtain mo2 = g（qσuvGuvq）/（qq） 0.68 GeV2, which is in good agreement with the QCD sum rules estimate mo2=（0.8± 0.2） GeV2.展开更多
By means of a formal expression of Cornwall-Jackiw-Tomboulis effective potential for quark propagator at finite temperatures and finite quark chemical potentials, we derive the real-time thermal Schwinger-Dyson equati...By means of a formal expression of Cornwall-Jackiw-Tomboulis effective potential for quark propagator at finite temperatures and finite quark chemical potentials, we derive the real-time thermal Schwinger-Dyson equation for quark propagator in Landau gauge. Denote the inverse quark propagator by A（p^2）ψ - B（p^2）, we argue that, when temperature T is lower than the given infrared momentum cutoff pc, A（p^2） = 1 is a feasible approximation and can be assumed in discussions of chiral symmetry phase transition problem in QCD.展开更多
Assuming that the recently θ＋ and other exotic resonances belong to the pentaquark i0 of SU（3）I with J^P = 1/2, we constructed a relativistic effective lagrangian in the frame work of baryon chiral perturbation th...Assuming that the recently θ＋ and other exotic resonances belong to the pentaquark i0 of SU（3）I with J^P = 1/2, we constructed a relativistic effective lagrangian in the frame work of baryon chiral perturbation theory. The masses of pentaquarks under isospin symmetry is determined by calculating the propagator to one loop, where the extended on-mass-shell renormalization scheme is applied. Using the experimental data for masses of θ＋, Ξ and N, we estimated the mass of Σ and the a terms.展开更多
Based on the Dyson-Schwinger equations in raAnbow approximation for quark propagator with an effective gluon propagator, and on the parametrized fully dressed quark propagator proposed by us, the unknown GasserLeutwyl...Based on the Dyson-Schwinger equations in raAnbow approximation for quark propagator with an effective gluon propagator, and on the parametrized fully dressed quark propagator proposed by us, the unknown GasserLeutwyler coeiticients of the chiral Lagrangian for pseudoscalar Goldstone bosons, Li, are predicted respectively. The predicted values of Li in the two different ways are not only in reasonable agreement each other but also in agreement with empirical values used widely in literature and the values predicted by many other theoretical models with QCD characteristics. The compatible results of Gasser-Leutwyler coefficients predicted by our parameterized quark propagator, in turn, clearly verify its extensive validity.展开更多
By differentiating the inverse dressed quark propagator at finite chemical potential μ with respect to μ, the linear response of the dressed quark propagato r to the chemical potential can be obtained, From this we ...By differentiating the inverse dressed quark propagator at finite chemical potential μ with respect to μ, the linear response of the dressed quark propagato r to the chemical potential can be obtained, From this we extract a modelindependent formula for the linear chemical potential dependence of the in-medium two-quark condensate and show by two independent methods （explicit calculation and Lorentz covariance arguments） that the first-order contribution in μ to the in-medium two-quark condensate vanishes identically. Therefore if one wants to study the in-medium two-quark condensate one should expand to at/east the second order in the chemical potential μ.展开更多
Using the Schwinger Dyson equation and perturbation theory,we calculate the two-quark condensates forthe light quarks u,d,strange quark s and a heavy quark c with their current masses respectively.The results show tha...Using the Schwinger Dyson equation and perturbation theory,we calculate the two-quark condensates forthe light quarks u,d,strange quark s and a heavy quark c with their current masses respectively.The results show thatthe two-quark condensate will decrease when the quark mass increases,which hints the chiral symmetry may be restoredfor the heavy quarks.展开更多
In a nonlinear chiral SU(3) framework, we investigate the quark condensate in the strange matter including and Λ, making use of chiral symmetry spontaneous breaking Lagrangian and mean-field approximation. The resul...In a nonlinear chiral SU(3) framework, we investigate the quark condensate in the strange matter including and Λ, making use of chiral symmetry spontaneous breaking Lagrangian and mean-field approximation. The results show that the chiral symmetry is restored partially when the strange matter density increases and that plays a very important role in the strange matter which may approach the constituents of the neutron stars. In addition, we can find that the strange matter density where the π-condensate emerges leads to the ratio of the nucleon number to baryon number.展开更多
In this review article we give a brief overview on some recent progress in quark pairings in dense quark/nuclear matter mostly developed in the past five years.We focus on following aspects in particular:the BCS-BEC c...In this review article we give a brief overview on some recent progress in quark pairings in dense quark/nuclear matter mostly developed in the past five years.We focus on following aspects in particular:the BCS-BEC crossover in the CSC phase,the baryon formation and dissociation in dense quark/nuclear matter,the Ginzburg-Landau theory for three-flavor dense matter with UA(1) anomaly,and the collective and Nambu-Goldstone modes for the spin-one CSC.展开更多
Direct extrapolation of the strong interaction between quarks in pure perturbative calculation has a problem of thermodynamic inconsistency. A new term determined by thermodynamic consistency requirement could resolve...Direct extrapolation of the strong interaction between quarks in pure perturbative calculation has a problem of thermodynamic inconsistency. A new term determined by thermodynamic consistency requirement could resolve it. This new term plays an important role at lower density in describing the equation of state of quark matter, while it is negligible at high density. Accordingly, the density behavior of the sotmd velocity becomes more reasonable, and the maximum mass of quark stars can be as large as two times the solar mass.展开更多
基金The project supported by National Natural Science Foundation of China and the Special Research Fund for Doctor Programs of the Chinese Universities
文摘The newly observed D^＊aj family containing D^＊aj（2317）, Daj（2460）, and Daj（2632） attracts great interests. Determining their structures may be an important task for both theorists and experimentalists. In this work we use a non-relativistic model （the harmonic oscillator model） to evaluate the production rate of D^＊aj （2317） from the decays of ψ（4415）. For a comparison, we a/so employ the widely adopted heavy quark effective theory to repeat the calculation. We lind that the rate is sizable and may be observed at BES III and CLEO, if it is a p-wave excited state of Da（1968）. Unfortunately, the other two members of the family cannot be observed through decays of charmonia, because of the constraints from the final state phase space.
基金supported by National Natural Science Foundation of China under Grant No.10778719
文摘In this paper, firstly, we investigate the neutrino emissivity from quark Urca process in strong magnetic field. Then, we discuss the heat capacity of strange stars in strong magnetic field. Finally, we give the cooling curve in strong magnetic field. In order to make a comparison, we also give the corresponding cooling curve in the case of null magnetic field. It turns out that strange stars cool faster in strong magnetic field than that without magnetic field.
文摘With the diquark structure of ∧c, we investigate the branching ratio of ∧c→nπ^+ and pπ^0. The results show that without considering the finM state interaction (FSI), the branching ratio of ∧c→pπ^0 is only of order 10^-6 whereas this ratio could reach 10^-4 and is at the same order as ∧c→nπ^+ if taking into account the FSI effects. Concrete values depend on phenomenologicM parameters adopted in the calculations. These branching ratios can be measured in the experiments to come.
基金The project supported by National Natural Science Foundation of China under Grant No. 10405009 and the Key Program Foundation of North China Electric Power University
文摘In this article, we study the pentaquark state Θ＋（1540） with a （scalar） diquark-（pseudoscalar） diquarkantiquark type interpolating current in the framework of the QCD sum rules approach by including the contributions from the direct instantons. The numerical results indicate that the contributions from the direct instantons are very small and can be safely neglected.
基金Supported in part by the Key Research Plan of Theoretical Physics and Cross Science of China under Grant No. 90503011National Science Foundation under Grant No. 10775012
文摘Using the Dyson-Schwinger equation and perturbation theory, we calculate the mixed quark-gluon condensates in the chiral limit and in the case of nonzero quark current mass for the light quark u/d and strange quark s. The results show that the mixed quark-gluon condensate will decrease when the quark mass increases. For the quark with zero mass, we obtain mo2 = g（qσuvGuvq）/（qq） 0.68 GeV2, which is in good agreement with the QCD sum rules estimate mo2=（0.8± 0.2） GeV2.
文摘By means of a formal expression of Cornwall-Jackiw-Tomboulis effective potential for quark propagator at finite temperatures and finite quark chemical potentials, we derive the real-time thermal Schwinger-Dyson equation for quark propagator in Landau gauge. Denote the inverse quark propagator by A（p^2）ψ - B（p^2）, we argue that, when temperature T is lower than the given infrared momentum cutoff pc, A（p^2） = 1 is a feasible approximation and can be assumed in discussions of chiral symmetry phase transition problem in QCD.
基金The project supported in part by National Natural Science Foundation of China under Grant No. 90103018.
文摘Assuming that the recently θ＋ and other exotic resonances belong to the pentaquark i0 of SU（3）I with J^P = 1/2, we constructed a relativistic effective lagrangian in the frame work of baryon chiral perturbation theory. The masses of pentaquarks under isospin symmetry is determined by calculating the propagator to one loop, where the extended on-mass-shell renormalization scheme is applied. Using the experimental data for masses of θ＋, Ξ and N, we estimated the mass of Σ and the a terms.
基金The project supported in part by National Natural Science Foundation of China under Grant Nos. 10565001, 10435080, and 10575123 and the Natural Science Foundation of Guangxi Province of China under Grant Nos. 0542042, 0575020, and 0481030
文摘Based on the Dyson-Schwinger equations in raAnbow approximation for quark propagator with an effective gluon propagator, and on the parametrized fully dressed quark propagator proposed by us, the unknown GasserLeutwyler coeiticients of the chiral Lagrangian for pseudoscalar Goldstone bosons, Li, are predicted respectively. The predicted values of Li in the two different ways are not only in reasonable agreement each other but also in agreement with empirical values used widely in literature and the values predicted by many other theoretical models with QCD characteristics. The compatible results of Gasser-Leutwyler coefficients predicted by our parameterized quark propagator, in turn, clearly verify its extensive validity.
基金The project supported in part by National Natural Science Foundation of China under Grant Nos. 10175033, 10135030, 10575050, and 10475057, and the Research Fund for the Doctoral Program of Higher Education under Grant No. 20030284009
文摘By differentiating the inverse dressed quark propagator at finite chemical potential μ with respect to μ, the linear response of the dressed quark propagato r to the chemical potential can be obtained, From this we extract a modelindependent formula for the linear chemical potential dependence of the in-medium two-quark condensate and show by two independent methods （explicit calculation and Lorentz covariance arguments） that the first-order contribution in μ to the in-medium two-quark condensate vanishes identically. Therefore if one wants to study the in-medium two-quark condensate one should expand to at/east the second order in the chemical potential μ.
基金Supported in part by the Key Research Plan of Theoretical Physics and Cross Science of China under Grant No.90503011National Natural Science Foundation under Grant No.10775012
文摘Using the Schwinger Dyson equation and perturbation theory,we calculate the two-quark condensates forthe light quarks u,d,strange quark s and a heavy quark c with their current masses respectively.The results show thatthe two-quark condensate will decrease when the quark mass increases,which hints the chiral symmetry may be restoredfor the heavy quarks.
基金Key Research Plan of Theoretical Physics and Cross Science，国家自然科学基金
文摘In a nonlinear chiral SU(3) framework, we investigate the quark condensate in the strange matter including and Λ, making use of chiral symmetry spontaneous breaking Lagrangian and mean-field approximation. The results show that the chiral symmetry is restored partially when the strange matter density increases and that plays a very important role in the strange matter which may approach the constituents of the neutron stars. In addition, we can find that the strange matter density where the π-condensate emerges leads to the ratio of the nucleon number to baryon number.
基金Supported by the National Natural Science Foundation of China under Grant No. 10735040
文摘In this review article we give a brief overview on some recent progress in quark pairings in dense quark/nuclear matter mostly developed in the past five years.We focus on following aspects in particular:the BCS-BEC crossover in the CSC phase,the baryon formation and dissociation in dense quark/nuclear matter,the Ginzburg-Landau theory for three-flavor dense matter with UA(1) anomaly,and the collective and Nambu-Goldstone modes for the spin-one CSC.
基金supported by the National Natural Science Foundation of China(Grant Nos.11135011 and 11475110)the Key Project from Chinese Academy of Sciences(Grant No.KJCX3-SYW-N2)
文摘Direct extrapolation of the strong interaction between quarks in pure perturbative calculation has a problem of thermodynamic inconsistency. A new term determined by thermodynamic consistency requirement could resolve it. This new term plays an important role at lower density in describing the equation of state of quark matter, while it is negligible at high density. Accordingly, the density behavior of the sotmd velocity becomes more reasonable, and the maximum mass of quark stars can be as large as two times the solar mass.
