Mass spectra of meson molecular states for heavy and light sectors

We obtain mass spectra of the light and heavy meson-antimeson(molecular states) sectors by using a nonrelativistic potential model with Coulomb and one pion exchange potential terms for meson-meson interaction.The digamma decay widths are also obtained for the light sector.We compare our results with available experimental and theoretical data.     

A NEW POTENTIAL MODEL

A new phenomenological potential model on interaction between quark and antiquark is proposed by the hint of QCD and experimental data. Spectroscopies, leptonic decay and electromagnetic transition widths of the heavy quarkonia, cc, bb and tt, are calculated using nonrelativistic SchrÖdinger equation with numerical method. The most results of the model are well consistent with experimental data.     

Binding energy effects in the decay properties of charmonia

The di-gamma and di-gluon decay widths of P-wave cc mesons are computed in nonrelativistic phenomenological quark-antiquark potential of the type V (r) =-4 3 α s r+ Ar ν with different choices of ν using spectroscopic parameters.The numerically obtained radial solutions are employed to obtain the di-gamma and di-gluon decay widths.The computed decay widths are consistent with other model predictions as well as with the known experimental values in the range of potential index 0.7 ≤ν≤ 1.1.     

Vector and Tensor Coupling Constants of SU(3) Baryons in a Chiral Soliton Model

We report in the present talk a recent investigation on the vector properties of SU(3) baryons, based on a chiral soliton model. All relevant parameters from the model are adjusted to the experimental data of the masses and magnetic moments of the baryon octet. We compute the electromagnetic transitions for the baryon octet, the decuplet, and the antidecuplet. The numerical predictions for transition magnetic moments and radiative partial decay widths are in a very good agreement with all data of existing experiment and the vector meson dominance being used, the coupling constants for the vector mesons and antidecuplet baryon vertices are determined from the calculated transition magnetic moments.     

$$Q\bar{Q}$$ ($$Q\in \{b,c\}$$Q∈{b,c}) spectroscopy using the Cornell potential

The mass spectra and decay properties of heavy quarkonia are computed in nonrelativistic quark-antiquark Cornell potential model. We have employed the numerical solution of Schrödinger equation to obtain their mass spectra using only four parameters namely quark mass (\(m_c\), \(m_b\)) and confinement strength (\(A_{c\bar{c}}\), \(A_{b\bar{b}}\)). The spin hyperfine, spin-orbit and tensor components of the one gluon exchange interaction are computed perturbatively to determine the mass spectra of excited S, P, D and F states. Digamma, digluon and dilepton decays of these mesons are computed using the model parameters and numerical wave functions. The predicted spectroscopy and decay properties for quarkonia are found to be consistent with available data from experiments, lattice QCD and other theoretical approaches. We also compute mass spectra and life time of the \(B_c\) meson without additional parameters. The computed electromagnetic transition widths of heavy quarkonia and \(B_c\) mesons are in tune with available experimental data and other theoretical approaches.     

Electromagnetic transition properties of→Nγ in a hypercentral scheme

The electromagnetic transition properties of the decuplet to octet baryon (→ Nγ) is studied within the framework of a hypercentral quark model.The confinement potential is assumed as a hypercentral coloumb plus linear potential.The transition magnetic moment and transition amplitude f M 1 for the → Nγ are in agreement with other theoretical predictions.The present result of the radiative decay width is found to be in excellent agreement with the experimental values reported by the particle data group over other theoretical model predictions.     

Decays of Dsj*(2317) and Dsj(2460) Mesons in the Quark Model

We study the decay widths of the narrow resonances D_sj^*(2317) and D_sj(2460) in the chiral quark model, together with the well-known D^* and D_s^* mesons. All the parameters in our calculation are taken from Godfrey and Isgur's quark model except the π⁰－η mixing angle which is fixed by the D_s^* decay widths. The calculated electromagnetic decay widths agree with those from other groups and the experimental data available quite well. However, the pionic decay widths of D_sj(2317) and D_sj(2460) are too small to fit the experimental data. We suspect that the simple chiral quark pion axial-vector interaction Hamiltonian is not suitable for hadron strong decays of D_sj(2317) and D_sj(2460).     

Electromagnetic Coupling of Negative Parity Nucleon Resonances N(1535) Based on Nonrelativistic Constituent Quark Model

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.     

Mass Spectrum and Decay Properties of D Meson

A comparative study of the spectroscopy and decay properties of the D meson is carried out within the framework of phenomenological quark-antiquark potential (Coulomb plus power) model using hydrogenic and Gaussian wave function. The spin-hyperfine, spin-orbit and tensor interactions are employed to obtain the pseudoscalar and vector meson masses incorporating the effect of mixing. The decay constants (f _P/V ) are computed with QCD correction using the wave function at the origin. The leptonic branching fractions and electromagnetic transition rates are also calculated in this scheme. Our predictions at potential index ν=1 are in good agreement with experimental results as well as lattice and other theoretical models.     

A theory of phase transitions in solid krypton and xenon monolayers on graphite

A statistical mechanical model of solid Kr and Xe monolayers on graphite is described. A phase transition in a Kr monolayer is interpreted as a transition from a solid localised in the surface potential wells of the graphite, to an unlocalised solid having a higher density. Comparison with experimental data enables the graphite well depth to be estimated. Explicit calculations are presented for four different interatomic potential models. The density of the unlocalised phase, the isosteric heat, and the gas-solid transition are given as a function of temperature and pressure for both Kr and Xe. It is shown that Xe first condenses into an unlocalised phase, and its ability to undergo a transition into localisation is examined. It is found that this transition is unlikely at p ? 10^?3 Torr where volumetric measurements have been made, but may occur at lower pressures. The gas-solid transition data is re-interpreted in terms of a transition to the unlocalised phase. A combination of the solid-solid and gas-solid transition data is shown to be a good test of interatomic potential models. The comparison is made with particular reference to the magnitude of the Sinanoglu-Pitzer potential.     

Elastic and inelastic form factors of baryons in a quark-potential-model

Starting from a Dirac equation with a scalar linear confinement potential for quarks we calculate the electromagnetic and weak form factors of the nucleon and the magnetic transition form factor of the Δ(1232). Taking the Lorentz transformation of the quark wave functions into account the results compare well with the experimental data.     

多腔体复杂系统电磁脉冲耦合统计特性

以双腔体级联系统为实验对象,测量了系统的输出端感应电压,对实验结果进行统计分析,并与随机拓扑模型计算结果进行对比,两者基本吻合,验证了随机拓扑模型的适用性;利用该模型计算分析了不同脉冲参数及不同拓扑结构条件下多混沌腔体复杂系统的电磁耦合统计特性。研究表明,脉冲宽度和脉冲个数与概率峰值处的感应电压均存在一定的谐振特性,且脉冲频率越低,脉冲的耦合效率越高,采用串型的拓扑结构更加有利于系统的防护和加固。     

Nonleptonic Interactions of Kaons in the Quark Confinement Model

Nonleptonic, electromagnetic decays of K-mesons and K°–K̄° transition are treated with the effective Hamiltonians with ΔS = 1, 2. Matrix elements of four-quark operators are calculated in the framework of Quark Confinement Model. The account of the intermediate scalar mesons turns out to allow to explain ΔI = 1/2 rule. The account of intermediate scalar and pseudo-scalar states leads to experimental value of mass difference of K_L°–K_S° mesons. The obtained values for nonleptonic and electromagnetic decay widths as well as mass difference Δm_LS are in good agreement with experimental data.     

Saturation effects in pionic atoms and the π−-nucleus optical potential

The optical model for pionic atoms is used to fit measurements over a range of nuclei with a particular emphasis on the apparently anomalous behaviour of the atomic shifts and widths in Na(1s), As(2p) and Ta(3d). Several modifications of the Ericson-Ericson potential are considered and a laplacian form of potential also examined. These do not improve the fit to the anomalous results. The reliability of the experimental data is discussed.     

(η−η′−ι)-mixing,decay and production mechanisms

We present a phenomenological model for meson-glueball mixing and apply it to the mixing of the pseudoscalar mesons η and η′ with the ι(1440)-particle as the prime candidate for a 0^?+-glueball. Using the MIT bag model framework, our model incorporates, among other elements, configuration mixing effects due to virtually excited states, as well as mixing of quark and gluon components. We evaluate the portions of quark antiquark and two-gluon admixtures in η,η′ and ι. The results are used to study various decay and production processes involving these particles. In particular, we calculate the radiative and the 2γ-decay widths of the light mesons and make predictions for the widths of the ι in these channels. Furthermore, production mechanisms of the light mesons in electromagnetic and hadronicJ/ψ-decays are used to evaluate the branching ratios for the production of the ι in variousJ/ψ-transitions. Our results are generally in reasonable agreement with experimental data. Especially we predict a rather large width for the decay ι→ργ and a sizable production rate for the ι in the transitionJ/ψ→ωι.     

Reconstruction of the 2D hole gas spectrum for selectively doped <Emphasis Type="Italic">p</Emphasis>-Ge/Ge<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>S<Subscript>ix</Subscript> heterostructures

The magnetic field (0≤B≤32 T) and temperature (0.1≤T≤15 K) dependences of longitudinal and Hall resistivities have been investigated for p-Ge_0.93Si_0.07/Ge multilayers with different Ge layer widths 12≤d _w ≤20 nm and hole densities p _s =(1–5)×10¹⁵ m^?2. An extremely high sensitivity of the experimental data (the structure of magnetoresistance traces, relative values of the inter-Landau-level gaps deduced from the activation magnetotransport, etc.) to the quantum well profile is revealed in the cases where the Fermi level reaches the second confinement subband. An unusually high density of localized states between the Landau levels is deduced from the data. Two models for the long-range random impurity potential (the model with randomly distributed charged centers located outside the conducting layer and the model of the system with a spacer) are used to evaluate the impurity potential fluctuation characteristics: the random potential amplitude, the nonlinear screening length in the vicinity of integer filling factors v=1 and v=2, and the background density of states (DOS). The described models are suitable for explanation of the observed DOS values, while the short-range impurity potential models fail. For half-integer filling factors, a linear temperature dependence of the effective quantum Hall effect plateau-plateau (PP) transition widths v₀(T) is observed, contrary to the expected scaling behavior of the systems with short-range disorder. The finite T→0 width of the PP transitions may be due to an effective low-temperature screening of a smooth random potential due to the Coulomb repulsion of electrons.     

E1 radiation decay of isobaric analog resonances

Within the framework of the shell-optical model a quantitative interpretation for partial E1 radiation widths of isobaric analog resonances (IAR) has been proposed for near-magic nuclei over a wide atomic mass range. Spin-flip transitions as well as non-spin-flip ones are considered. A dependence of polarization effects on the spin-isospin part of the quasiparticle effective interaction is cleared up for transitions of different type. The results of calculations are compared with the experimental data.     

Partial α-decay half-lives of ground to ground and ground to excited states of Thorium family

Partial half-lives and Q-values of allowed α-decay for Thorium family are evaluated by using the WKB approximation. In order to calculate the partial half-lives, transition probabilities from ground to ground and ground to excited states of daughter nuclei are obtained. The α-decay potential barrier includes deformed volume, surface, and Coulomb parts in the deformed liquid drop model (DLDM), deformed Woods-Saxon nuclear potential and centrifugal term. The quadrupole and the hexadecapole deformations are considered in the calculations. Calculated half-lives are compared to the results of other theoretical models as well as experimental data. Comparison of the present study and other theoretical methods with experimental data indicated that the predicted half-lives using current approach are well agreed with the experimental data than results of UMADAC and CPPMDN theoretical models. Moreover, the evaluated half-lives correspond well with the Geiger-Nuttall empirical formula.