Zhi-Gang Wang
In this article, we assign the $Y(4390)$ and $Y(4220)$ to be the vector molecular states $D\bar{D}_1(2420)$ and $D^*\bar{D}_0^*(2400)$, respectively, and study their masses and pole residues with the QCD sum rules in details. The present calculations only favor assigning the $Y(4390)$ to be the $D\bar{D}_1(1^{--})$ molecular state.
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Contents: 1. Introduction. 2. Sum rules prior to QCD. 3. Dispersion relations. 4. Types of two point function sum rules. 5. Non-perturbative power corrections. 6. Some examples of QCD sum rules.
The coupling constant of f0-->omega-gamma decay is calculated using 3-point sum rule and light cone QCD sum rules. We investigate the results within the two-models which depend on mixing angle.
In this article, the tensor-vector-pseudoscalar type of vertex is analyzed with the QCD sum rules and the local-QCD sum rules. Correspondingly, the hadronic coupling constants of D2*(2460), Ds2*(2573), B2*(5747) and Bs2*(5840), and their decay widths are calculated. The results indicate that the QCD sum rules and the local-QCD sum rules give the consistent descriptions. Finally, the full widths of these 4 tensor mesons are discussed in detail.
The current status of the QCD sum rule predictions for charmed mesons is overviewed.
QCD Sum Rule and Perturbative QCD Approaches to Pion Compton Scattering
我们比较了两种方法来描述的π介子康普顿散射在中等动量转移，一个是基于本地对偶QCD求和规则的不变振幅的过程中，这是最近推导出来的，和其他修改的因式分解公式与Sudakov效应。我们发现，微扰QCD预测是占主导地位的那些从QCD求和规则，只有散射角大于90 $^o$。
Decay constant of eta-meson f is calculated on the basis of the QCD sum rule method. An instanton contribution is taken into account. The result is f = 0.17 GeV.
We investigate the a0-omega-gamma vertex and estimate the coupling constant in the framework of the light cone QCD sum rules. We compare our result with the value of the coupling constant was calculated in the QCD sum rules.
Recently, a QCD sum-rule analysis of tetraquark molecular states has been published, having the objective of demonstrating that our previously formulated tetraquark-adequate QCD sum rules are not correct. This comment brings to the attention of the reader inconsistencies in that article and explains some subtle details of QCD sum rules for exotic states.
I give a short summary of QCD sum rule results for hadrons involving a heavy quark, with emphasis on recent developments.
We review the DPD sum rules and establish their validity to all orders in QCD. This is done using a diagrammatic approach and light-front perturbation theory. In the process we furthermore investigate the QCD evolution of double parton distributions and obtain sum rules for $1\to2$ splitting kernels in close analogy to the DPD sum rules themselves.
QCD sum rules vs. chiral perturbation theory
QCD求和规则是研究强子光谱性质的有用工具，然而，标准求和规则分析的假设可能导致与手征微扰理论的已知结果不一致。用QCD求和规则提取核子质量和$σ$项证明了这种可能性。在这两种情况下，不一致的手性行为导致$\sim 100\,\text{MeV}$的求和规则预测的不确定性。
We examine the problem of constructing spectral representations for two point correlation functions, needed to write down the QCD sum rules in the medium. We suggest constructing them from the Feynman diagrams for the correlation functions. As an example we use this procedure to write the QCD sum rules for the nucleon current at finite temperature.
QCD Sum Rules: The Second Decade
在“QCD -- 20年后”会议上的特邀演讲，1992年6月9日至13日，德国亚琛
$π$-$A_1$ electromagnetic form factors and light-cone QCD sum rules
用增加扭曲的波函数描述π介子，用QCD求和规则计算了跃迁$π+γ_{virt.}\ra A_1$的电磁形状因子。将获得的结果与标准QCD求和规则计算进行比较。
The pentaquark width is calculated in QCD sum rules. The higher dimension operators contribution is accounted. It is shown, that $Γ_Θ$ should be very small, less than $1Mev$.
In "Landau equation and QCD sum rules for the tetraquark molecular states", I list out six reasons to refute the assertion of Lucha, Melikhov and Sazdjian. In "Comment on "Landau equation and QCD sum rules for the tetraquark molecular states"", they refute my viewpoint. If they want to the refute my viewpoint robustly, they should refute the six reasons one by one, and provide at least one example to illustrate that they have obtained reliable QCD sum rules for the tetraquark states and free two-meson states, respectively.
We give an overview over recent calculations of baryonic correlator functions with finite mass quarks in view on their applicability for QCD sum rules. The QCD sum rule method is then demonstrated within the Heavy Quark Effective Theory.
Heavy Quark Masses from QCD Sum Rules
我回顾了最近的决定（上壳）的魅力和美夸克质量的相对论和非相对论的拉普拉斯变换QCD矩和规则的比例的框架。讨论了非相对论性QCD求和规则在这一特殊应用中的有效性。
I present a compilation of results on B->light meson form factors from QCD sum rules on the light-cone.
The strong coupling constants g_{K LAMBDA N} and g_{K SIGMA N} for the structure (sigma_{mu,nu} gamma_5) are calculated within light cone QCD sum rules. A comparison of our results on these couplings with predictions from traditional QCD sum rules is presented.
Direct Instantons in QCD Nucleon Sum Rules
本文研究了直接（即小尺度）瞬子在核子QCD关联函数中的作用。它们对传统的算子乘积展开产生了相当大的非微扰修正，从而提高了QCD核子求和规则的质量，并解决了长期存在的稳定性问题，特别是手征奇求和规则。
In this talk, we give a short review of our recent works on studying the singly heavy baryon, doubly heavy baryon, and triply heavy baryon spectra from QCD sum rules.
Recently the μ_{Δ^{++}} was found from a fit to (π^+)p scattering. This enable us to pinpoint condensate parameters more precisely in the context of QCD sum rules (QCDSR). In the octet sector, the Coleman-Glashow sum rule (CGSR) is violated by the experimental μ-s. QCDSR allows us to write down two sum rules similar to the CGSR, which are obeyed by the experimental magnetic moments, whereas they rule out a specific model using the Wilson loop approach and a particular chiral quark model. It is amusing to note that the QCDSR allows us to write down the quark and gluon condensates in terms of me…
New relations between QCD Borel sum rules for magnetic moments of Sigma^0 and Lambda hyperons are constructed. It is shown that starting from the sum rule for the Sigma^0 hyperon magnetic moment it is straightforward to obtain the corresponding sum rule for the Lambda hyperon magnetic moment et vice versa.
Masses of the p-wave excited heavy baryons have been calculated to the Lambda_{QCD}/m_Q order using QCD sum rule method within the framework of heavy quark effective theory. Numerical results for kinetic energy lambda_1 and chromo-magnetic interaction lambda_2 are presented. The splitting between spin 1/2 and 3/2 doublet derived from our calculation is given, for which the agreement with the current experiment is desirable.
Exclusive Semileptonic and Rare Radiative B Decays from QCD Sum Rules
本文综述了QCD求和规则对B介子弱衰变到轻强子（和轻子）的形状因子的预测
We consider the two point correlation function of scalar current in QCD sum rules approach to estimate the overlap amplitude of $a_0$ meson. We then employ QCD sum rules to calculate the coupling constants g$_{ωa_0γ}$ and g$_{ρa_0γ}$ by studying the three point ${a_0ωγ}$- and ${a_0ργ}$-correlation functions.
We use the method of QCD Sum Rules to estimate the masses of the charm baryon, $Λ^+_c$, bottom baryon $Λ^0_b$, strange baryon $Λ^0_s$ and compare them to their experimental values.
The coupling constant of g_phi-pion-gamma decay is calculated using light cone QCD sum rules. A comparison of our result with the ones existing in the literature is presented.
Revisiting the QCD sum-rule description of exotic hadron states, we argue that, in order to arrive at trustable analyses of, for instance, strong decay widths of multiquarks, it is inevitable to adopt the QCD sum-rule approach beyond the leading perturbative level.
In this article, we perform a systematic study of the mass spectrum of the scalar doubly charmed and doubly bottom tetraquark states using the QCD sum rules.
The $Σ$--$Λ$ mixing angle is calculated in framework of the QCD sum rules. We find that our prediction for the mixing angle is $(1.00\pm 0.15)^0$ which is in good agreement with the quark model prediction, and approximately two times larger than the recent lattice QCD calculations.
Momentum Sum Rules in QCD for a Photon Target
我们推导了光子靶部分子结构函数的动量和规则。非微扰QCD贡献的动量和规则遵循能量-动量张量守恒，它是通过光子真空极化算子的强子部分计算的。未分辨光子的贡献明确地遵循QCD中的规范不变性、可重整化性和渐近自由。我们还比较了现有的参数化的部分子在光子中的分布与推导的求和规则。
We calculate the leading twist valence quark distribution in the pion in the franework of QCD sum rules with nonlocal condensates. Particular attention has been paid to the correct account of the bilocal power corrections.
The magnetic and quadrupole moments of the light-vector and axial-vector mesons are calculated in the light cone QCD sum rules. Our results for the static properties of these mesons are compared with the predictions of lattice QCD as well as other approaches existing in the literature.
In this article, we use the light-cone QCD sum rules to relate the $Λ_b$ baryon light-cone distribution amplitudes to the Isgur-Wise function $ξ(ω)$ of the $Λ_b \to Λ_c$ transition, and obtain a simple relation. The numerical value of the Isgur-Wise function $ξ(ω)$ is consistent with the prediction of the QCD sum rules.
Violation of the Bjorken Sum Rule in QCD
我们证明了在考虑轴向反常的情况下，极化核子结构函数$g_1$一阶矩的Bjorken求和规则在QCD中不一定满足。我们认为，非微扰QCD效应应导致违反的总和规则的顺序的百分比同位旋违反当前夸克质量。
We calculate the on-shell $Σ^0$-$Λ$ mixing parameter $θ$ with the method of QCD sum rule. Our result is $θ(m^2_{Σ^0}) =(-)(0.5\pm 0.1)$MeV. The electromagnetic interaction is not included.
We use QCD sum rules to determine the difference between moments of the non-singlet structure functions. This combination decouples from the singular behaviour of the structure functions near x=1 as calculated in the quark-gluon basis and thus should lead to improved sum rule predictions. However, we find there are still very large errors due to higher order corrections. In order to refine the error analysis, we study the effect of renormalon ambiguities on our QCD sum rules results.
We calculate the form factors V, A_1, A_2 and A_0 appearing in the (D -> phi) transition in light cone QCD sum rule method. We compare our results on these form factors with the current experimental results and existing theoretical calculations.
By matching the world of hadrons to that of some effective chiral quark theory, we determine the induced condensates for QCD sum rules in the presence of an external pion field. The observed values of the strong and weak $πNN$ coupling constants are understood.
We calculate the leading twist valence quark distribution in the pion in the framework of QCD sum rules with nonlocal condensates. Particular attention has been paid to the correct account for the bilocal power corrections.
This paper has been withdrawn by the author since the comments have been withdrawn.
The axial N-> Delta(1232) transition form factors are calculated within the light cone QCD sum rules method. A comparison of our results with predictions of lattice theory and quark model calculations is pre- sented.
We investigate the $ωσγ$-vertex and estimate the coupling constant g$_{ωσγ}$ in the framework of the light cone QCD sum rules. We compare our result with the values of this coupling constant deduced from a phenomenological analysis of $ω\toππγ$ decays.
We try to find the grounds for the standard nucleon QCD sum rules, based on more detailed description of QCD vacuum. We calculate the polarization operator of the nucleon current in the instanton medium. The medium (QCD vacuum) is assumed to be a composition of the small-size instantons and some long-wave gluon fluctuations. We solve the corresponding QCD sum rules equations and demonstrate that there is a solution with the value of the nucleon mass close to the physical one if the fraction of the small size instantons contribution w_s \approx 2/3.
In this article, we restudy the mass spectrum of the ground state triply-heavy baryon states with the QCD sum rules by carrying out the operator product expansion up to the vacuum condensates of dimension 6 in a consistent way and preforming a novel analysis. It is the first time to take into account the three-gluon condensates in the QCD sum rules for the triply-heavy baryon states.
We present predictions for rho-meson form factors obtained from the analysis of QCD sum rules in next-to-leading order of perturbation theory. The radiative corrections turn out to be sizeable and should be taken into account in rigorous theoretical analysis.
The coupling constant of g_phi-pi-gamma decay is calculated in the method of QCD sum rules. A comparison of our prediction on the coupling constant with the result obtained from analysis of the experimental data is performed.
A new analysis of baryon sum rules is done with modern values of parameters and known perturbative corrections. The restriction for gluon and quark condensates and the new value of nucleon coupling constant are found.
In this article, we investigate the mass spectrum of the ground state hidden-charm tetraquark molecular states without strange, with strange and with hidden-strange via the QCD sum rules in a comprehensive way and revisit the assignments of the $X$, $Y$, $Z$ states in the scenario of tetraquark molecular states consistently based on the QCD sum rules.
Heavy-to-Light Form Factors from QCD Sum Rules on the Light-Cone
我们讨论了基于增加扭曲的光锥上的π波函数展开和QCD求和规则方法的$B \rightarrow π$和$D \rightarrow π$形状因子的计算。结果与传统的QCD求和规则和其他方法的预测进行了比较。
This work presents the results of our analysis of the accuracy of the pion form factor derived from the local-duality version of QCD sum rules.
The rho-meson magnetic moment is calculated in the framework of QCD sum rules in external fields. Bare loop calculations (parton model) give 2.0. The contribution of the operators of dimension 6 reduces this value to 1.5.
The leading-twist distribution amplitude for the longitudinal rho-meson was studied using QCD Sum Rules with nonlocal condensates and a spectral density which includes next-to-leading order radiative corrections. The obtained profile is compared with results from standard QCD sum rules, lattice QCD, holographic QCD, a light-front quark model, and the instanton liquid model. Preliminary estimates for the first two moments of the transverse $ρ$-meson distribute amplitude are also given.
QCD sum rule is applied to the pentaquark spectroscopy. It is concluded that no positive parity state is seen in low energy region, while there may exist negative parity states at around 1.5 GeV. Choice of interpolating local operators and relation to the lattice calculations are discussed.
The radiative decays of heavy baryons and lowest three doublets of heavy mesons are studied with the light cone QCD sum rules in the leading order of heavy quark effective theory.
Alpha_s from spectroscopy of psi- and Upsilon-particles in QCD sum rules
在QCD求和规则的一个特定方案中，人们根据$ψ$ -和$Υ$ -粒子的质量和轻子常数的数据给出了$α_S\simeq 0.20$的估计。
QCD Sum Rules and B Decays
本文综述了QCD求和规则在$B$ -衰变中的应用。其中包括确定轻子常数$f_B$和$B$介子到正负宇称粲态的半轻子跃迁振幅。
In the present work, the temperature dependence of the scalar mesons parameters is investigated in the framework of thermal QCD sum rules. We calculate sigma-pole and the non-resonant two-pion continuum contributions to the spectral density. Taking into account additional operators appearing at finite temperature, the thermal QCD sum rules are derived. The temperature dependence of the shifts in the mass and leptonic decay constant of scalar sigma(600) meson is calculated.
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