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Propagators for Scalar Bound States at Finite Temperature in an njl model

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Communications in Theoretical Physics 2002年第3期37卷 303-308页

作者： ZHOUBang－Rong DepartmentofPhysics GraduateSchooloftheChineseAcademyofSciencesBeijing100039China

We re-examine physical causal propagators for scalar and pseudoscalar bound states at finite temperature in a chiral njl model, defined by four-point amputated functions subtracted through the gap equation, and prove that they are completely equivalent in the imaginary-time and real-time formalisms by separating carefully the imaginary part of the zero-temperature loop integral. It is shown that the same thermal transformation matrix of the matrix propagators for these bound states in the real-time formalism is precisely the one of the matrix propagator for an elementary scalar particle and this fact shows the similarity of thermodynamic property between a composite and elementary scalar particle. The retarded and advanced propagators for these bound states are also given explicitly from the imaginary-time formalism.

关键词： njl model thermal field theory the imaginary-time and real-time formalisms four-point amputated functions imaginary part of zero-temperature loop

(Pseudo) Scalar mesons in a self-consistent njl model

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Chinese Physics C 2023年第12期47卷 40-44页

作者：俞笑竹王昕杨 Department of Physics Jiangsu UniversityZhenjiang 212013China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China

In this study, we investigate the mass spectra of π and σ mesons at finite chemical potential using theself-consistent njl model and the Fierz-transformed interaction Lagrangian. The model introduces an arbitrary parameterα to reflect the weights of the Fierz-transformed interaction channels. We show that, when α exceeds a certainthreshold value, the chiral phase transition transforms from a first-order one to a smooth crossover, which is evidentfrom the behaviors of the chiral condensates and meson masses. Additionally, at a high chemical potential, the smallerthe value of α, the higher the masses of the π and σ mesons. Moreover, the Mott and dissociation chemical potentialsincrease with the increase in α. Thus, the meson mass emerges as a valuable experimental observable for determiningthe value of α and investigating the properties of the chiral phase transition in dense QCD matter.

关键词： njl model chiral phase transition meson

Pion-photon and kaon-photon transition distribution amplitudes in the Nambu–Jona-Lasinio model

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Chinese Physics C 2024年第8期48卷 94-103页

作者： Jin-Li Zhang Jun Wu Department of Mathematics and Physics Nanjing Institute of TechnologyNanjing 211167China National Laboratory of Solid State Microstructures Department of PhysicsNanjing UniversityNanjing 210093China

The Nambu–Jona-Lasinio model is utilized to investigate the pion-and kaon-photon leading-twist transition distribution amplitudes using proper time ***,the properties of the vector and axial vector pion-photon transition distribution amplitudes are examined,and the results meet the desired *** study involves sum rule and polynomiality *** vector and axial vector pion-photon transition form factors that are present in theπ^(+)→γe^(+)νprocess are the first Mellin moments of the pion-photon transition distribution *** vector transition form factor originates from the internal structure of hadrons,the axial current can be coupled to a pion,this pion is virtual,and its contribution will be present independently of the external *** kaon transition form factors are *** vector form factor's value at zero momentum transfer is determined by the axial anomaly,while this is not the case for the axial *** vector and axial form factors,as well as the neutral pion vector form factor F_(πγγ)(t),are *** to our findings,the pion axial transition form factor is harder than the vector transition form factor and harder than the electromagnetic form *** also discuss the link betweenπ−γandγ−πtransitions distribution amplitudes.

关键词： transition form factors njl model transition distribution amplitudes

Phenomenological study of the anisotropic quark matter in the two-flavor Nambu–Jona–Lasinio model

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Nuclear Science and Techniques 2022年第11期33卷 170-190页

作者： He-Xia Zhang Yu-Xin Xiao Jin-Wen Kang Ben-Wei Zhang Key Laboratory of Quark and Lepton Physics(MOE)and Institute of Particle Physics Central China Normal UniversityWuhan 430079China Guangdong Provincial Key Laboratory of Nuclear Science Institute of Quantum MatterSouth China Normal UniversityGuangzhou 510006China

With the two-flavor Nambu–Jona–Lasinio (njl) model, we carried out a phenomenological study on the chiral phase structure, mesonic properties, and transport properties of momentum-space anisotropic quark matter. To calculate the transport coefficients we utilized the kinetic theory in the relaxation time approximation, where the momentum anisotropy is embedded in the estimation of both the distribution function and relaxation time. It was shown that an increase in the anisotropy parameterξmay result in a catalysis of chiral symmetry breaking. The critical endpoint(CEP) is shifted to lower temperatures and larger quark chemical potentials asξincreases, and the impact of momentum anisotropy on the CEP temperature is almost the same as that on the quark chemical potential of the CEP. The meson masses and the associated decay widths also exhibit a significant ξ dependence. It was observed that the temperature behavior of the scaled shear viscosity η/T~3 and scaled electrical conductivity σ/T exhibited a similar dip structure, with the minima of both η/T~3 and σ/T shifting toward higher temperatures with increasing ξ. Furthermore,we demonstrated that the Seebeck coefficient S decreases when the temperature rises and its sign is positive, indicating that the dominant carriers for converting the temperature gradient to the electric field are up-quarks. The Seebeck coefficient S is significantly enhanced with a largeξfor a temperature below the critical temperature.

关键词： Heavy-ion collision Momentum anisotropy njl model Chiral phase transition Transport coefficient Quark matter

Exploring light-cone distribution amplitudes from quantum computing

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Science China(Physics,Mechanics & Astronomy) 2023年第8期66卷 57-65页

作者： Tianyin Li Xingyu Guo Wai Kin Lai Xiaohui Liu Enke Wang Hongxi Xing Dan-Bo Zhang Shi-Liang Zhu Guangdong Provincial Key Laboratory of Nuclear Science Institute of Quantum MatterSouth China Normal UniversityGuangzhou 510006China Guangdong-Hong Kong Joint Laboratory of Quantum Matter Southern Nuclear Science Computing Center South China Normal University.Guangzhou 510006China Department of Physics and Astronomy University of CaliforniaLos Angeles 90095USA Center of Advanced Quantum Studies Department of PhysicsBeijing Normal UniversityBejing 100875China Center for High Energy Physics Peking UniversityBeijing 100871China Guangdong-Hong Kong Joint Laboratory of Quantum Matter Frontier Research Institute for PhysicsSouth China Normal UniversityGuangzhou 510006China Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials School of Physics and Telecommunication EngineeringSouth China Normal UniversityGuangzhou 510006China

Light-cone distribution amplitudes(LCDAs)are essential nonperturbative quantities for theoretical predictions of exclusive highenergy processes in quantum chromodynamics(QCD).We demonstrate the prospect of calculating LCDAs on a quantum computer by applying a recently proposed quantum algorithm,with staggered fermions,to the simulation of the LCDA in the(1+1)-dimensional Nambu-Jona-Lasinio(njl)model on classical *** agreement between the result from the classical simulation of the quantum algorithm and that from exact diagonalization justifies the proposed quantum *** find that the resulting LCDA in the njl model exhibits features shared with the LCDAs obtained from the QCD.

关键词： light-cone distribution amplitude quantum algorithm njl model

Mass spectra and decay of mesons under strong external magnetic field

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Chinese Physics C 2022年第4期46卷 70-78页

作者： Shuyun Yang Meng Jin Defu Hou Institute of Particle Physics and Key Laboratory of Quark and Lepton Physics(MOS) Central China Normal UniversityWuhan 430079China

We study the mass spectra and decay process of σ and π_(0) mesons under a strong external magnetic *** achieve this goal,we deduce the thermodynamic potential in a two-flavor,hot and magnetized Nambu-Jona-Lasinio *** calculate the energy gap equation through the random phase approximation(RPA).Then we use the Ritus method to calculate the decay triangle diagram and self-energy in the presence of a constant magnetic field *** results indicate that the magnetic field has little influence on the mass of π_(0) at low ***,for quarks andσmesons,their mass clearly changes,which reflects the influence of magnetic catalysis(MC).The presence of a magnetic field accelerates the decay of the meson while the presence of a chemical potential will decrease the decay process.

关键词： magnetic field njl model decay constant mass spectra

Calculations of ■(p^6) Resonance Coupling Constants in Scalar Sector of Enjl model

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Communications in Theoretical Physics 2008年第5期49卷 1275-1278页

作者： XIAO Ling-Yi SU Ming-Xian Department of Physics Peking University Beijing 100871 China

We derive the scalar resonance coupling constants of resonance chiral theory from the extended Nambu Jona-Lasinio model by using heat-kernel expansion.

关键词： chiral Lagrangian njl model heat-kernel expansion

Phase diagram of two-color QCD matter at finite baryon and axial isospin densities

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Chinese Physics C 2020年第3期44卷 129-136页

作者： Jingyi Chao Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China

We study the two-color QCD matter with two fundamental quark flavors using the chiral perturbation theory and the Nambu-Jona-Lasinio(njl)*** effective Lagrangian is derived in terms of mesons and baryons,*** low lying excitations lie in the extended SU(4)flavor symmetry *** compute the leading order terms of the Lagrangian as a function of the baryon and axial isospin *** numerically solving the gap equations in the two-color njl model,the phase diagram is obtained in the μ−ν5 plane.

关键词： two-color QCD diquarks chiral perturbation theory axial isospin density njl model

Meson electro-magnetic form factors in an extended Nambu–Jona-Lasinio model including heavy quark flavors

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Chinese Physics C 2015年第11期39卷 17-23页

作者：栾义龙陈晓林邓卫真 School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking University

Based on an extended njl model including heavy quark flavors, we calculate the form factors of pseudoscalar and vector mesons. After taking into account the vector-meson-dominance effect, which introduces a form factor correction to the quark vector coupling vertices, the form factors and electric radii of π^＋ and K^＋ pseudo-scalar mesons in the light flavor sector fit the experimental data well. The magnetic moments of the light vector mesons ρ^＋and K^＊＋are comparable with other theoretical calculations. The form factors in the light-heavy flavor sector are presented to compare with future experiments or other theoretical calculations.

关键词： njl model heavy meson form factor magnetic moment