Analysis of Scalar Doubly Heavy Tetraquark States with QCD Sum Rules

In this article, we perform a detailed study of the mass spectrum of the scalar doubly charmed and doubly bottom tetraquark states using the QCD sum rules.

Analysis of the decay B^0→χc1~π~0 with light-cone QCD sum rules

In this article, we calculate the contribution from the nonfactorizable soft hadronic matrix element to the decay B^0→Xc1π^0 with the light-cone quantum chromo-dynamic （QCD） sum rules. The numerical results show that its contribution is rather large and should not be neglected. The total amplitudes lead to a branching fraction which is in agreement with the experimental data marginally.

Fermion Corrections to Mass of Scalar Glueball in QCD Sum Rule

Contributions of fermions to the mass of the scalar glueball 0++are calculated at two-loop level in theframework of QCD sum rules.It slightly changes the coefficients in the operator product expansion （OPE） and shiftsthe mass of glueball to 1.72 ± 0.07 GeV.

Reanalyzing Pentaquark Θ^＋（1540） in Framework of QCD Sum Rules Approach with Direct Instantons

In this article, we study the pentaquark state Θ＋（1540） with a （scalar） diquark-（pseudoscalar） diquarkantiquark type interpolating current in the framework of the QCD sum rules approach by including the contributions from the direct instantons. The numerical results indicate that the contributions from the direct instantons are very small and can be safely neglected.

A Comparative Study of f_B within QCD Sum Rules with Two Typical Correlators up to Next-to-Leading Order

The B-meson decay constant fB is an important component for studying the B-meson decays, which can be studied through QCD sum rules. We make a detailed discussion on f B from two sum rules up to next-to- leading order, i.e. sum rules I and II, which are derived from the conventional correlator and the correlator with chiral currents respectively. It is found that these two sum rules are consistent with each other. The sum rules H involves less non-perturbative condensates as that of sum rules I, and in principle, it can be more accurate if we know the dimensionfour gluon condensate well. It is found that fB decreases with the increment of mb, and to compare with the Belle experimental data on fB, both sum rules I and H prefer smaller pole b-quark mass, mb= 4.68 ± 0.07 GeV. By varying all the input parameters within their reasonable regions and by adding all the uncertainties in quadrature, we obtain fB=172-25^＋23 MeV for sum rules I and fB =214-34^26 MeV for sum rules П.

{Q}{^(('))s}Molecular States in QCD Sum Rules

We systematically investigate the mass spectra of {Qs}{Q（＇）s} molecular states in the framework of QCD sum rules. The interpolating currents representing the molecular states are proposed. Technically, contributions of the operators up to dimension six are included in operator product expansion （OPE）. The masses for molecular states with various {Qs}{Q（＇）s} configurations are presented. The result 4.36 ± 0.08 Ge V for theDs＊ Ds0- ＊ molecular state is consistent with the mass 4350＋4.6 -5.1± 0.7 MeV of the newly observed X（4350）, which could support X（4350） interpreted as a D＊D＊so molecular state.

Analysis of Y(4660) and Related Bound States with QCD Sum Rules

In this article, we take the vector charmonium-like state Y（4660） as a φ＇ fo（980） bound state （irrespective of the hadro-charmonium and the molecular state） tentatively, and study its mass using the QCD sum rules. The numerical value My = 4.71 ±0.26 GeV is consistent with the experimental data. Considering the SU（3） symmetry of the light flavor quarks and the heavy quark symmetry, we also study the bound states φ＇a（400-1200）, γ′″ fo（980）, and γ′″σ（400-1200） with the QCD sum rules, and make reasonable predictions for their masses.

Nuclear symmetry energy from QCD sum rules

We calculated the nucleon self-energies in iso-spin asymmetric nuclear matter and obtained the nuclear symmetry energy by taking difference of these of neutron and proton.We find that the scalar(vector) self-energy part gives a negative(positive) contribution to the nuclear symmetry energy,consistent with the result from relativistic mean-field theories.Also,we found exact four-quark operator product expansion for nucleon sum rule.Among them,twist-4 matrix elements which can be extracted from deep inelastic scattering experiment constitute an essential part in the origin of the nuclear symmetry energy from QCD.Our result also extends early success of QCD sum rule in the symmetric nuclear matter to the asymmetric nuclear matter.

Strong decay of Y(4230)→ J/ψ f0(980) in light cone sum rules

In this study,we assign the tetraquark state for the Y(4230) resonance and investigate the mass and decay constant of Y(4230) in the framework of SVZ sum rules through a different calculation technique.Then,we calculate the strong coupling gYJ/ψf0 by considering soft-meson approximation techniques within the framework of light cone sum rules,and we use the strong coupling gYJ/ψf0 to obtain the width of the decay Y(4230)→J/ψf0(980).Our prediction for the mass agrees with the experimental measurement,and that for the decay width of Y(4230)→J/ψf0(980) is within the upper limit.

0^(--) hidden-heavy tetraquark states via QCD sum rules

In this study,we evaluated the mass spectra of the prospective 0^(--) hidden-charm and hidden-bottom tetraquark states in molecular configuration via QCD sum rules.In our calculation,the nonperturbative condensate contributions are considered up to dimension eight in operator product expansion.It is found that there could exist 4possible 0^(--) hidden-charm tetraquark states with masses(4.68±0.07),(4.22±0.09),(4.53±0.09),and(4.26±0.13) GeV.Their corresponding hidden-bottom partners are found lying at(11.04±0.10),(10.71±0.12),(11.09±0.10),and(11.82±0.14) GeV,respectively.The possible tetraquark decay modes were analyzed,which are expected to be measured in BESⅢ,BELLEⅡ,and LHCb experiments.

QCD sum rule study of J^(P)=1^(±)exotic states with two heavy quarks in the molecular picture

In this study,the spectroscopic parameters of exotic molecular states composed of mesons containing two heavy quarks(scalar-axial and pseudoscalar-axial meson combinations)are investigated within the QCD sum rules.Our findings reveal that molecular states containing charm quarks do not form bound states,whereas states with b-quarks can form exotic molecular states.This observation has significant implications for understanding the structure of these exotic states.

Strong decays of the P_(c)(4312) and its isospin cousin via the QCD sum rules

In this study,considering the conservation of isospin in the strong decays,we investigate the strong decays of the pentaquark molecule candidate P_(c)(4312)and its possible higher isospin cousin P_(c)(4330)in the framework of the QCD sum rules.Further,the pole residue of theΔbaryon with isospin eigenstate|II3>=|3/21/2)is obtained.If the possible pentaquark molecule candidate P_(c)(4330)could be determined,it would shed light on the interpretations of the P_(c) states in future experiments.

Ground states and first radial excitations of vector tetraquark states with explicit P-waves via QCD sum rules

In this study,we chose the diquark-antidiquark type four-quark cuents with an explicit P-wave betweenthe diquark and antidiquark pairs to study the ground states and first radial exeitations of the hidden-charm tetra.quark states with quantum numbers J^(PC)=1^(--).We also obtained the lowest vector tetraguark masses and made pos.sible assignments of the existing Ystates,There indeed exists a hidden-charm tetraquark state with J^(PC)=1^(--) at anenergy of approximately 4.75 GeV as the first radial exeitation that accounts for the BESIII data.

B_(c) meson and its scalar cousin with QCD sum rules

In this study,we use the optical theorem to calculate the next-to-leading order corrections to the QCD spectral densities directly in the QCD sum rules for the pseudoscalar and scalar B_(c) mesons.We use experimental data for guidance to perform an updated analysis.We obtain the masses and,in particular,decay constants,which are the fundamental input parameters in high energy physics.Ultimately,we obtain the pure leptonic decay widths,which can be compared with experimental data in the future.

Fully-light vector tetraquark states with explicit P-wave via QCD sum rules

In this study,we apply the QCD sum rules to investigate the vector fully-light tetraquark states with an explicit P-wave between the diquark and antidiquark pairs.We observed that the Cγα⊗↔∂μ⊗γαC(or Cγα⊗↔Dμ⊗γαC)type current with fully-strange quarks couples potentially to a tetraquark state with a mass 2.16±0.14GeV,which supports assigning Y(2175)/ϕ(2170)as the diquark-antidiquark type tetraquark state with JPC=1−−.The qsˉqˉs and ssˉsˉs vector tetraquark states with the structure Cγμ⊗↔∂α⊗γαC+Cγα⊗↔∂α⊗γμ(or Cγμ⊗↔Dα⊗γαC+Cγα⊗↔Dα⊗γμ)are consistent with X(2200)and X(2400),respectively,which lie in the region from 2.20 to 2.40GeV.The central values of the masses of the fully-strange vector tetraquark states with an explicit P-wave are approximately 2.16−3.13GeV(or 2.16−3.16GeV).Predictions for other fully-light vector tetraquark states with and without hidden-strange are also presented.

多分类器组合及其应用

1 引言传统的模式识别系统通常只使用样本的某种单一特征描述和特定的一个分类器来进行分类。这种系统对于类别数较大、输入样本带噪声的问题很难获得好的分类效果。近来发现不同的特征描述、不同的分类器在分类性能上存在着彼此互补的现象,因此同时使用多种特征描述和多个分类器可能提高分类精确性。目前,多分类器组合的研究吸引了学者们广泛的注意。

铍原子低激发态能量的计算

以对角和不变法则为基础,导出了铍原子(含类铍离子)低激发态(电子组态1S22S2P、1S22P2)非相对论性能量的解析表达式;利用变分法计算了能量值,计算结果与实验值的误差小于1%.

碳原子基态能量的计算

以对角和不变法则为基础,导出了碳原子(含类碳离子Z=6→8)基态(电子组态为1s22s22p2)非相对论性能量的解析表达式,并利用变分法计算了能量值,计算结果与实验数据符合的较好,误差小于0.2%.

一个实用的电子评审方案

电子评审是一种特殊的电子选举,由于投票人很少,直接使用现有电子选举方案很难实现安全评审.本文将改进的矩阵传送安全多方求和协议与保密比较协议相结合,采用少数服从多数的选举规则,秘密比较计票结果是否大于一个预定门限值,不泄露计票值就能得出评审结果.该方案具有投票的隐私性、无收据性、计票的保密性和无争议性等性质,满足安全评审的需求;计算代价和通信代价均低于现有方案,容易设计实用的系统.

综合联想记忆神经网络的外积取等准则

本文提出了一个新的联想记忆设计准则，即外积取等准则，它具有外积和准则的所有优点。由外积取等准则设计出的联想记忆网络能够存储任意给定的训练模式，即对于训练模式的数目和它们之间相关性的强弱没有限制。外积取等准则可用来定量地评价记忆模式向量各分量对于记忆模式分类或识别的重要性。由外积取等准则设计出的网络的连接权值只取１、０或－１，因而网络易于光学实现。计算机实验结果充分说明了外积取等准则的有效性。