Meson decays in an extended Nambu—Jona-Lasinio model with heavy quark flavors

In a previous work,we proposed an extended Nambu-Jona-Lasinio(NJL)model including heavy quark flavors.In this work,we will calculate strong and radiative decays of vector mesons in this extended NJL model,including lightρ,ω,K*,(?)and heavy D~*,D_s~*,B~*,B_s~*.     

Study of the heavy molecular states in the quark model with meson exchange interaction

Some charmonium-like resonances such as X(3872) can be interpreted as possible D^(*)D^(*) molecular states. Within the quark model, we study the structure of such molecular states and the similar B^(*)D^(*) molecular states by taking into account the light meson exchange (π, η, ρ, ω and σ) between two light quarks from different mesons.     

Meson decays in an extended Nambu-Jona-Lasinio model with heavy quark flavors

In a previous work, we proposed an extended Nmnbu-Jona-Lasinio （NJL） model including heavy quark flavors. In this work, we will calculate strong and radiative decays of vector mesons in this extended NJL model, including light p, w, K＊, θ and heavy D＊, D＊s, B＊, Bs＊.     

Ratios ofB andD meson decay constants with heavy quark symmetry

SU(3) flavor symmetry allows the decay constantsf _{D 1} andf _{D 2} as well asf _{B 1} andf _{B 1} to be equal. But due toSU(3) flavor symmetry breaking the ratiosf _{B 1}/f _{B 2} andf _{D 1}/f _{D 2} are deviated from unity. We have estimated these ratios in the heavy quark effective theory and obtainedf _{B 1}/f _{B 2}=0.93,f _{D 1}/f _{D 2}=0.94 and the double ratio (f _{B 1}/f _{B 2})/(f _{D 1}/f _{D 2})=0.99.     

Mass spectra of light and heavy mesons in the-Dirac equation with power-law potential

The mass spectra of both light and heavy mesons are studied in the Dirac equation with an equally mixed 4-vector and scalar power-law potential model. This potential provides an excellent fit not only to the mass spectra ofp°, ϕ, Ψ and υ families but also to those ofD, F andB mesons. The light quark masses inp° and ϕ as well as in atom-like mesons are very close to the current quark masses.     

ρ meson decays of heavy hybrid mesons

We calculate the ρ meson couplings between the heavy hybrid doublets H~h/S~h/M~h/T~h and the ordinary qQˉ doublets in the framework of the light-cone QCD sum rule. The sum rules obtained rely mildly on the Borel parameters in their working regions. The resulting coupling constants are rather small in most cases.     

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.     

Open quantum system approach for heavy quark thermalization

We treat heavy quark as an open quantum system in a hot medium and rederive the stochastic Schr?dinger equation (SSE) from the full Schr?dinger equation for both heavy quarks and the medium. We apply the SSE to the dynamical evolutions of a heavy quark (as a system) in the static hot medium (as an environment). Heavy quarks interact with the medium via random scatterings, which exchange the momentum and phase factor randomly between two wave functions of the system and the environment. The exchange of momentum and phase factor results in the transition between different eigenstates of the system. These are included via an external stochastic potential in the Hamiltonian of SSE. Stochastic wave functions of a heavy quark are evolved with the stochastic external potential. The mean wave functions and corresponding momentum distributions of heavy quarks are obtained after the ensemble average over a large set of stochastic wave functions. We present the thermalization of heavy quarks in the static medium with different coupling strengths.     

Meson spectra governed by the Fermi-Breit potential

We calculate the meson mass spectra in a quark potential model by using the complete Fermi-Breit potential including the terms of orbit-orbit interaction, spin-orbit coupling, and tensor force interaction. We find that these terms give nontrivial contributions to the calculated meson spectra. The orbit-orbit coupling term may lead to an instability of the solution of the Schrodinger equation and should be regularized.     

Meson spectra with a power-law potential in the Dirac equation

A power law potential which is an equal admixture of scalar and vector parts with effective powerv ∞ 1/m _q , is proposed as a quark confining potential in the Dirac equation. The model is capable of predicting the meson spectroscopy encompassing both light and heavy quark-antiquark systems in a unified way.     

Meson spectra governed by the Fermi-Breit potential

We calculate the meson mass spectra in a quark potential model by using the complete Fermi-Breit potential including the terms of orbit-orbit interaction, spin-orbit coupling, and tensor force interaction. We find that these terms give nontrivial contributions to the calculated meson spectra. The orbit-orbit coupling term may lead to an instability of the solution of the Schr5dinger equation and should be regularized.     

Heavy quark spin symmetry and heavy flavor hadronic molecules

We argue that the heavy quark spin symmetry can lead to important consequences for heavy flavor hadronic molecules.It can be used to predict new heavy flavor hadronic molecules and hence provides a method to identify the nature of some newly observed exotic hadrons.For example,if the Y（4660） were an S-wave ψ f 0 （980） shallow bound state,then the mass,width and line shape of its spin partner are predicted.     

Heavy quark spin symmetry and heavy flavor hadronic molecules

We argue that the heavy quark spin symmetry can lead to important consequences for heavy flavor hadronic molecules.It can be used to predict new heavy flavor hadronic molecules and hence provides a method to identify the nature of some newly observed exotic hadrons.For example,if the Y(4660) were an S-wave ψ f 0 (980) shallow bound state,then the mass,width and line shape of its spin partner are predicted.     

Relativistic quark model with quantum chromodynamics, P-states of quarkonia and scalar-vector confinement

In this paper we try to understand several phenomenological issues related to the mass spectra of P-states quarkonia in a relativistic quark model. We give particular emphasis on understanding the most recent experimental data within a relativized scalar-vector confining potential. In this paper we extend the previous works on the studies of quark confinement in non-relativistic QCD, using a formalism which uses a covariant Hamiltonian in the centre of mass frame. The spin-structure of the potential is obtained from the reduction of Bethe-Salpeter equation into Breit-interaction. Printed as S Chakrabarty in several papers published earlier e.g. References [1,11] etc. of this paper.     

坐标空间中构造的Breit夸克势与介子和夸克偶素的质量劈裂

构造夸克间的有效的相互作用势函数是强子物理中的重要研究课题,也是学科前沿问题之一.本文对坐标空间中的Breit夸克势函数的完整形式实施消除奇异因子的替代方法,构造出一个有效的夸克势.除了第一项库仑势和第七项常数项势,对其他的项都需进行重新构造,即对第二项和第四项做δ(r)→μ~3e~(-μr)/8π替代,对第三项做1/r→(1-e-μr)/r替代,对第五项和第六项做1/r~3→1-(1+μr)e~(-μr)/r~3替代,由此重新构造出新的势函数,然后用来计算质量劈裂,检验构造势的有效性.为此计算了一组含重介子和夸克偶素的质量劈裂.计算中屏蔽质量μ不是简单的常数,而是取与夸克质量m_i,m_j有关的变量.研究计算发现,只有当屏蔽质量μ取为关于夸克平均质量μ_a=(m_i+m_j)/2的洛朗级数形式μ=c_(-3)(μ_a+0.512)-3+c_(-2)(μ_a+0.512)~(-2)+c_(-1)(μ_a+0.512)~(-1)+c_0+c_1(μ_a+0.512)时重介子η_c-J/ψ,η_b-Υ(1s),还有χ_(c0)-χ_(c1)-χ_(c2)等的夸克偶素之间质量劈裂精确达到实验值,同时其他介子尤其是6个D介子质量精度都比以往得到较大幅度的改善.因此,本文构造出一个有效的夸克势模型.     

在具有伸缩子的QCD势模型中的重介子

从伸缩子–胶子有效耦合理论得到的重夸克–反夸克势模型出发,计算了重介子的自旋平均能谱及轻子衰变和辐射跃迁宽度,并与Cornell势模型所得到的相应结果作了比较.结果表明,新的重夸克势的计算结果与重介子的实验数据更好地符合,而且估计的伸缩子质量5?7MeV很好地位于有关伸缩子质量的其他理论途径所估计的范围之内.     

重夸克偶素质量谱的相对论夸克模型研究（已撤稿）

使用量子场论中准势途径的相对论夸克模型,计算了重夸克偶素的质量谱.所采用的同味正反夸克间的有效相互作用包括通常的直接单胶子交换、单胶子湮没及具有相对论修正的标量和矢量线性禁闭的混合.得到了与实验上肯定的数据符合较好的拟合计算结果，并讨论了湮没项和相对论修正各项对能谱超精细分裂的作用. 关键词： 重夸克偶素 质量谱 相对论修正 湮没势     

Light meson spectrum and their leptonic decay widths in the frame work of constituent quark models

The phenomenological non-relativistic quark model has been employed to obtain the ground state masses of light vector mesons and their radially excited states and their decay widths.The full hamiltonian used in the investigation has kinetic energy,the confinement potential and the one-gluon-exchange potential.A good agreement is obtained with the experimental masses and their leptonic decay widths.