Wang Zhi-Gang

Reanalysis of the Zc(4020), Zc(4025), Z(4050) and Z(4250) as Tetraquark States with QCD Sum Rules*

In this article, we calculate the contributions of the vacuum condensates up to dimension-10 in the operator product expansion, and study the C γμ- Cγνtype scalar, axial-vector and tensor tetraquark states in details with the QCD sum rules. In calculations, we use the formula μ = (M 2X/ Y /Z-(2Mc)2)~(1/2) to determine the energy scales of the QCD spectral densities. The predictions MJ =2=(4.02+0.09-0.09) GeV, MJ =1=(4.02+0.07-0.08) GeV favor assigning the Zc(4020) and Zc(4025) as the JP C= 1+-or 2++diquark-antidiquark type tetraquark states, while the prediction M++J =0=(3.85+0.15-0.09) GeV disfavors assigning the Z(4050) and Z(4250) as the JP C= 0diquark-antidiquark type tetraquark states. Furthermore, we discuss the strong decays of the 0++, 1+-, 2++diquark-antidiquark type tetraquark states in details.In this article, we calculate the contributions of the vacuum condensates up to dimension-10 in the operator product expansion, and study the Cγμ — Cγν type scalar, axial-vector and tensor tetraquark states in details with the QCD sum rules. In calculations, we use the formula to determine the energy scales of the QCD spectral densities. The predictions favor assigning the Zc(4020) and Zc(4025) as the JPC = 1+− or 2++ diquark-antidiquark type tetraquark states, while the prediction disfavors assigning the Z(4050) and Z(4250) as the JPC = 0++ diquark-antidiquark type tetraquark states. Furthermore, we discuss the strong decays of the 0++, 1+−, 2++ diquark-antidiquark type tetraquark states in details.

Calculation of Chiral Lagrangian Coefficients

We present a systematic way to combine the global colour model and the instanton liquid model to calculate the chiral Lagrangian coefficients. Our numerical results are in agreement well with the experimental values.We present a systematic way to combine the global color model and the instanton liquid model to calculate the chiral Lagrangian coefficients. Our numerical results are in agreement well with the experimental values.

Semileptonic Decays B*c → ηcℓv̄ℓ with QCD Sum Rules

In this article, we calculate the B*c → ηc form-factors with the three-point QCD sum rules, then study the semileptonic decays B*c → ηclvl. The tiny decay widths may be observed experimentally in the future at the LHCb, while the B*c → ηc form-factors can be taken as basic input parameters in other phenomenological analysis.

Calculation of Kaon Electromagnetic Form Factor in the Framework of Coupled Schwinger—Dyson and Bethe—Salpeter Formulation

The kaon electromagnetic form factor is calculated in the framework of coupled Schwinger–Dyson equation in rainbow approximation and Bethe–Salpeter equation in ladder approximation with the modified flat-bottom potential, which is the combination of the flat-bottom potential with considerations for the infrared and ultraviolet asymptotic behaviours of the effective quark-gluon coupling. All our numerical results give good fit to experimental values and other theoretical results.

Calculation of the π Meson Electromagnetic Form Factor

The modified flat-bottom potential (MFBP) is given by the combination of the flat-bottom potential with considerations for the infrared and ultraviolet asymptotic behaviour of the effective quark-gluon coupling. The π meson electromagnetic form factor is calculated in the framework of the coupled Schwinger-Dyson equation and the Bethe-Salpeter equation in the simplified impulse approximation (dressed vertex) with the MFBP. All our numerical results give a good fit to experimental values.

Calculation of kaon electromagnetic form factor

The kaon meson electromagnetic form factor is calculated in the framework of coupled Schwinger-Dyson and Bethe-Salpeter formulation in simplified impulse approximation (dressed vertex) with modified flat-bottom potential, which is a combination of the flat-bottom potential taking into consideration the infrared and ultraviolet asymptotic behaviours of the effective quark-gluon coupling. All the numerical results give a good fit to experimental values.

A Novel Controllable Hybrid-Anode AlGaN/GaN Field-Effect Rectifier with Low Operation Voltage

A novel controllable hybrid-anode AlGaN/GaN field-effect rectifier (HA-FER) with low operation voltage (LOV) is proposed. Its mechanism can be explained by the field-controlled energy band model. This model reveals that the electric field in the AlGaN layer alters the energy band to result in a variation of the two-dimensional electron gas (2DEG) at AlGaN/GaN interface; the field can be changed by the thickness d of the AlGaN layer and the applied bias. As the d reduces below the critical thickness, the 2DEG vanishes and then the channel is pinched of. Therefore, the threshold voltage of HA-FER can be designed as low as 0 V leading to LOV (< 1 V). The analytical characteristic of the HA-FER is calculated and validated by the simulated results. These results also demonstrate that the forward properties of HA-FER are superior to the conventional SBD due to the high Schottky barrier.

Dynamical properties of two-band superlattices with strong interband coupling in real space under the action of ac and dc-ac fields

Within a two-band tight-binding model driven by ac and dc-ac electric fields, using numerical methods, we investigate the dynamics of electrons and the quasi-energy spectrum of the system with strong interband coupling in real space. We find that when the bandwidth is suppressed to a value much smaller than the field frequency, the dynamical localization can exist in the system. The corresponding regions are found for the occurrence of dynamical localization in the parameter space.

Free or Quasi-Free Electronic Density of States in a Confined Atom

A new general formula, for energy normalization of radial wave-functions of free electron and of quasi-free electron in confined atom, is derived in central field approximation, which can flexibly be applied to the cases of relativity, non-relativity, and of free atom.

Anomalous Hall effect of heavy holes in III-V semiconductor quantum wells

The anomalous Hall effect of heavy holes in semiconductor quantum wells is studied in the intrinsic transport regime, where the Berry curvature governs the Hall current properties. Based on the first–order perturbation of wave function the expression of the Hall conductivity the same as that from the semiclassical equation of motion of the Bloch particles is derived. The dependence of Hall conductivity on the system parameters is shown. The amplitude of Hall conductivity is found to be balanced by a competition between the Zeeman splitting and the spin–orbit splitting.