An Electromagnetic Form Factor of a Charged Scalar Meson with Schwinger-Dyson and Bethe-Salpeter Equations

The wave functions and electromagnetic form factor of charged scalar mesons are studied with a modified vectorvector fiat-bottom potential model under the framework of the Schwinger-Dyson and Bethe-Salpeter equations. The obtained results agree well with other theories.     

Electromagnetic Form Factor of Charged Scalar Meson

Wavefunctions and the electromagnetic form factor of charged scalar mesons are studied with the vector-vectortype fiat-bottom potential model under the framework of the spinor-spinor Bethe-Salpeter equation. The obtained results are in agreement with other theories.     

Light Flavor Vector and Pseudo Vector Mesons from a Light-Cone QCD Inspired Effective Hamiltonian Model with SU（3） Flavor Mixing Interactions

Based on the light-cone effective Hamiltonian with confining potential and SU （3） flavor mixing interactions, the flavor mixing mesons on the u, d, and s quark sectors are investigated. The mass eigen equations of the flavor mixing vector and pseudo vector mesons are solved. The calculated masses are in good agreement with the experimental data.     

A Light-Cone QCD Inspired Effective Hamiltonian Model for Pseudoscalar and Scalar Mesons

Considering the one-gluon exchange interaction and phenomenological quark confinement potential, an improved light-cone effective Hamiltonian for mesons and the corresponding radial mass eigen equations in angular momentum representation is obtained. Solving the J = 0 eigen equations numerically and using a set of adjustable parameters, the obtained solutions for ground states and radial excited states can simultaneously describe both pseudoscalar and scalar flavour-off-diagonal mesons. Some radial excited states are also predicted and wait for experimental test. More results for the vector and axial vector mesons are expected.     

The inverse problem in the case of bound states

We investigate the inverse problem for bound states in the D = 3 dimensional space. The potential is assumed to be local and spherically symmetric. The present method is based on relationships connecting the moments of the ground state density to the lowest energy of each state of angular momentum ?. The reconstruction of the density ρ(r) from its moments is achieved by means of the series expansion of its Fourier transform F(q). The large q-behavior is described by Padé approximants. The accuracy of the solution depends on the number of known moments. The uniqueness is achieved if this number is infinite. In practice, however, an accuracy better than 1% is obtained with a set of about 15 levels.The method is tested on a simple example, and applied to three different spectra.     

Assignment of Isodoublet of 2^3S1 Meson Nonet

Inserting the masses of some states, which have been established in theexperiments or the theory of lattice QCD, we investigate the mass of theisodoublet of the 2³S₁ meson nonet. The agreement results, 1567±22.6MeV and 1576.8MeV, are given by two different approaches. We suggest that the assignment of 2³S₁ meson nonet should be re-examined in future experiments.     

A Light-Cone QCD Inspired Effective Hamiltonian Model with SU（3） Flavor Mixing

The effective light-cone Harniltonian is extended to include the SU（3） flavor mixing interaction besides the confining potential. Solving the coupled J = 0 mass eigen equations for the up, down, and strange quark components numerically, the masses of π^0 and η, their radial wave functions, and rms radii are obtained in agreement with the experimental data.     

A Light-Cone QCD Inspired Meson Model with a Relativistic Confining Potential in Momentum Space

For describing the radial excited states a relativistic confining potential in momentum space is included in the meson effective light-cone Hamiltonian. The meson eigen equations are transformed from the front form to the instant form and formulated in total angular representation. Details about numerically solving these equations are discussed, mainly focusing on treating singularities arising from one-gluon exchange interactions and confinement. The results of pseudo-scalar mesons indicate that the improved meson effective light-cone Hamiltonian can describe the ground states and radial excited states well. Some radial excited states are also predicted and waiting for experimental test.     

Chiral Lagrangian Treatment of 0^＋＋ Mesons and 0^＋＋ Glueballs

Within the framework of a nonlinear chiral Lagrangian the mass spectra and the decay properties of 0^＋＋ states below 2 GeV are studied. Assuming that f0（980）, a0（980）, K0（1430）, and f0（1500） comprise an SU（3） nonet, we make a detailed prediction about the static properties of the 0^＋＋ mesons. The substructure analysis of these states in terms of two- and four-quark components as well as a glueball component is carried out. We also consider the interaction Lagrangian and provide a preliminary study of the strong and radiative decays of the 0＋＋ mesons. The scalar glueball masses and partial widths are also presented. In view of the fact that few data of 0＋＋ mesons are clearly given in the present PDG （Particle Data Group） list and that the four-quark content of mesons is a hot issue both experimentally and theoretically, the predicted results of the paper may be helpful for upcoming experimental and theoretical studies of these mesons.     

Electric Dipole Moment of W-boson Through Neutral Higga-Boson Exchange

We compute the electric dipole moment generated at two-loop for the W-boson in the Weinberg-Higgs model in which the CP violation is mediated by neutral Higgs-boson exchange. We also compare our results with the others relative to the problem in the literature     

矢量介子的辐射衰变

介子的辐射衰变是低能强子物理研究的重要方向, 通过它能够揭示介子的结构和性质。从有效场论的观点来看,介子衰变主要包含光子和强子之间的相互作用。使用SU(3)对称性和VMD模型分别对矢量介子的辐射衰变进行了研究。 通过对实验数据进行拟和,给出了在两种情形下V→Pγ的衰变宽度的理论值,并得到赝标量混合角θP 为－6°。 Radiative decay of mesons is an important aspect in low energy hadronic physics,through which structures and properties of mesons can be revealed. In view of effective field theories, the radiative decay of mesons involves mainly interactions between photons and hadrons. In this paper,we investigate the decay of vector mesons by using SU(3) symmetry and the vector meson dominance model respectively. By fitting with experiments, we give the theoretic widths for V→Pγ in both cases and the mixing angle of pseudoscalars θP is －6°.     

Prospects of Bc Mesons at the Compact Muon Solenoid

The results of two Monte Carlo generators for production of Bc mesons in pp collisions are compared at the large hadron collider energy √s = 14 TeV. In the study, the produced Bc mesons were forced to decay into the final states Bslv, Bsπ, J/ψlv, and J/ψπ. We have estimated that about 104 decays of Bc are expected to be recorded during the first year of the CMS running with a lepton trigger. Many Bc studies can be carried out by using these events with a statistical error at the level of 10^-2.     

Quantum chromodynamic quark benzene

A six-quark state with the benzene-like color structure based on a color string model is proposed and studied. Calculation with quadratic confinement with multi-string junctions shows that such a state has a ground state energy similar to that of other hidden color six-quark states proposed so far. Its possible effect on NN scattering is discussed.     

Monte Carlo Study on Singly Tagged D Mesons at BES-III

We present Monte Carlo studies on the singly tagged D mesons, which are crucial in the absolute measurements of D meson decays, based on a full Monte Carlo simulation for the BES-III detector, with the BES-III Offline Software System. The expected detection efficiencies and mass resolutions of the tagged D mesons are well estimated.     

Critical endpoint in the Polyakov-loop extended NJL model

The critical endpoint (CEP) and the phase structure are studied in the Polyakov-loop extended Nambu–Jona-Lasinio model in which the scalar type eight-quark (σ⁴${\sigma }^4$) interaction and the vector type four-quark interaction are newly added. The σ⁴${\sigma }^4$ interaction largely shifts the CEP toward higher temperature and lower chemical potential, while the vector type interaction does oppositely. At zero chemical potential, the σ⁴${\sigma }^4$ interaction moves the pseudo-critical temperature of the chiral phase transition to the vicinity of that of the deconfinement phase transition.     

Quark mass dependence of the pion vector form factor

We examine the quark mass dependence of the pion vector form factor, particularly the curvature (mean quartic radius). We focus our study on the consequences of assuming that the coupling constant of the ρ   to pions, g_ρππ$g_{\rho \pi \pi }$, is largely independent of the quark mass while the quark mass dependence of the ρ mass is given by recent lattice data. By employing the Omnès representation we can provide a very clean estimate for a certain combination of the curvature and the square radius, whose quark mass dependence could be determined from lattice computations. This study provides an independent access to the quark mass dependence of the ρππ   coupling and in this way a non-trivial check of the systematics of chiral extrapolations. We also provide an improved value for the curvature for physical values for the quark masses, namely 〈r⁴〉=0.73±0.09 fm⁴$〈r^4〉=0.73\pm 0.09{\text{fm}}^4$ or equivalently cV=4.00±0.50 GeV−4$c_V=4.00\pm 0.50{\text{GeV}}^{-4}$.