0++三胶子标胶球与QCD求和规则

计算了0⁺⁺三胶子标量流的两点函数,其中计及了直至量纲为6的凝聚项的贡献.在＂零宽度共振态加连续谱＂的谱函数模型中,得到了0⁺⁺三胶子标胶球的量子色动力学求和规则,由此定出了该标胶球的质量.     

ξ(2230)的胶子球解释

本文讨论了ξ(2230)作为胶子球解释的可能性.螺旋性振幅之比x和y的理论值与实验值的比较表明,ξ(2230)不可能是一个纯的2⁺⁺S波(或D波)的胶子球,但可能是一个4⁺⁺D波胶子球.     

2+1维U(1)格点胶球质量的变分计算

本文对具有严格基态解和正确经典连续极限的格点规范哈密顿量,采用变分法,计算了2+1维U(1)规范群0^+－和0⁺⁺胶子态的质量,在深度弱耦合区,得到am(0^+－)随1/g²增大而指数减少,而am(0⁺⁺)=2.78g².     

混合效应在QCD求和规则下对标量胶球质量的影响

在QCD求和规则的框架下考虑了纯胶球和普通介子态的混合效应对二者质量的影响.在关联函数的构造中,胶子流和夸克流都被认为既和胶球态有耦合,也和夸克态有耦合.利用QCD低能定理,构造了一个混合关联函数.通过这些关系及两共振态近似,得出了0⁺⁺胶球和夸克态的质量,它们与各自的纯态的质量相差不大.     

关于软坡密子的张量胶子球的内涵

通过把坡密子的轨迹跟观察到的量子数I^GJ^PC=0⁺2⁺⁺的同位旋标量的张量介子联系起来的关系,研究了坡密子的胶子球内涵.这些介子中有四个满足坡密子的自旋和质量的关系.这些坡密子的后选者可能是混合态.其中,f₂(2220)有极大的胶子球分量.讨论了关于这个介子宽度的实验争论,预言了它的理论下限,也阐明了在pp实验研究中观察不到f₂(2220)原因.     

(2+1)维SU(2)格点规范场胶球质量的解析计算

从连接图方案出发,计算0⁺⁺胶球质量,得到较好的标度行为     

用改进的格点哈密顿量计算2+1维QCD0++胶球质量

用改进的格点哈密顿量和截断本征方程法计算2+1维QCD 0⁺⁺胶球质量,结果显示较好的标度行为.     

反质子与核非弹性碰撞中的自旋效应

A(p,p)A*非弹性碰撞过程,若反质子的光学势包含了自旋轨道耦合势,它在碰撞过程中不但能激发正常宇称态,也能激发反常的宇称态,以及非弹性过程的极化度.本文在DWIA框架下导出了微分截面(dσ/dΩ)_f,i,极化度P(θ).并对入射能量为46.8MeV和179.7MeV ¹²C(p,p)¹²C*的2⁺,3^－和1⁺态微分截面、极化度进行严格的分波方法计算.计算与实验符合很好.由于反常宇称态的非弹过程已被测得,表明反质子光学势的自旋效应不容忽视.     

Pomeron的胶子内容

指出Pomeron可以被看作为具有Regge轨道α_p(t)=1.08+0.2GeV^－2t的Regge化的胶子球.理论成功地预言了实验上观测到的质子一质子弹性散射的总截面.理论与实验的最好符合给出了张量胶子球到质子反质子道的衰变宽度为9±3MeV,其总宽度大于50MeV.并且排除了张量胶子球的自旋为4的可能性.     

J/ψ辐射衰变中θ(1720)宽共振峰的矩分析

本文用矩分析法对J/ψ辐射衰变产生的θ(1720)宽共振峰的结构进行了研究.由于f'₂(1525)和θ(1720)二共振峰有重迭,为此我们讨论了2⁺⁺(f'₂(1525))+0⁺⁺+0⁺⁺和2⁺⁺(f'₂(1525))+0⁺⁺+2⁺⁺二种三态耦合结构模式,这对于弄清θ(1720)这个宽共振峰的结构,确定可能包含在其中的二个共振态,例如G(1590)和f₂(1720)的质量、宽度、自旋以及其它重要性质,进一步认识这二个令人关注的共振态是有帮助的.     

A Lattice Study of the Glueball Spectrum

Glueball Spectrum is studied using an improved gluonic action on asymmetric lattices in the pure SU(3) gauge theory.The smallest spatial lattice spacing is about 0.08 fm which makes the extrapolation to the continuum limit more reliable.In particular.attention is paid to the scalar glueball mass which is known to have problems in the extrapolation.Converting our lattice results to physical units using the scale set by the static quark potential,we obtain the following results for the glueball masses:MG(0 )=1730(90)MeV for the scalar glueball mass and MG(2 )=2400(95)MeV for the tensor glueball.     

Existence of Tensor Glueball ξ(2230) and Its Mass, Spin, and Decay Width

In order to solve the current experimental controversy on the existence of the tensor glueball ξ(2230), we examine whether the conclusion from Seth's experimental measurement, which rejects existence of ξ(2230), is reliable. We claim that the non-observation of the resonance structure by Seth is not a sound ground for rejecting the existence of ξ(2230) but it may just indicate that ξ(2230) has a broad width. We also study the tensor glueball properties: the mass, spin, and decay width. Our theoretical predictions of the mass and the spin of the ξ(2230) using QCD sum rule are about 2.23 GeV and J=2, respectively. Our theoretical results also evidently show that the ξ(2230) must have a total decay width of about 100 MeV, which is much broader than the reported 20 MeV but a small partial decay width of 2 MeV into pp decay channel.     

Vector meson J/ψ,φ electro-production in QCD

We study the vector meson electro-production off the proton in a QCD inspired model.A calculation of the differential cross section is performed for the J/ψ,φ meson off the proton.The theoretical results are consistent with the experimental data,and remind us to consider the contribution from the tensor glueball and Odderon to the differential cross section.Since gluons interact among themselves via self-interaction,the gluons can form a glueball with quantum numbers IG,JPC =0+,2++,with a decay width Γt =100 MeV and mass of mG = 2.23 GeV.The three gluons can form a three gluon color bound state with charge conjugation quantum number C =-1.This study is quite important to verify the validity of QCD and to search for new particles(tensor glueball and Odderon) as well as quest for new physics.     

The BES f<Subscript>0</Subscript>(1810): a new glueball candidate

We analyze the f₀(1810) state recently observed by the BES collaboration via radiative J/ψ decay to a resonant φω spectrum and confront it with DM2 data and glueball theory. The DM2 group only measured ωω decays and reported a pseudoscalar but no scalar resonance in this mass region. A rescattering mechanism from the open flavored KK̄ decay channel is considered to explain why the resonance is only seen in the flavor asymmetric ωφ branch along with a discussion of positive C-parity charmonia decays to strengthen the case for preferred open flavor glueball decays. We also calculate the total decay width of a glueball with this mass to be roughly 100 MeV, in agreement with the narrow, newly found f₀, and smaller than the expected estimate of 200–400 MeV. We conclude that this discovered scalar hadron deserves further experimental investigation, especially in the KK̄ channel, and if shown to be different from the f₀(1710), will become a solid glueball candidate. Finally we comment on other, but less likely, possible assignments for this state.     

瞬子效应在0++胶球的QCD求和规则中的作用

利用包含瞬子效应的QCD求和规则计算了0⁺⁺胶球的质量上限,结果为1.3GeV.还探讨了变动瞬子参量时对QCD求和规则的影响,发现包含瞬子修正的QCD求和规则在瞬子大小为1/3fm时变得很稳定     

QCD求和规则的张量胶子球(2++)的质量

利用量子色动力学求和规则计算了张量胶子球 (2++ )的质量 ,其结果与北京正负电子对撞机的BES实验组和MARKIII实验组的测量结果一致 ,表明张量胶子球的质量约 2 .2 3GeV左右。The mass of the tensor glueball (2 ++ ) is calculated in quantum chromodynamics(QCD) spectral sum rules. The theoretical prediction is in good agreement with the measurements of BES collaboration at BEPC, Beijing and MARK III, which indicates that the mass of the tensor glueball may be around 2.23 GeV.     

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 the framework of QCD sum rules. It slightly changes the coefficients in the operator product expansion (OPE) and shifts the mass of glueball to 1.72 ±0.07 GeV.     

ξ(2230) Is Likely to Be a Glueball

On the basis of the recent results of ξ(2230) → π⁺π^-, pp and ξ(2230) → K⁺K^-, K_sK_s, measured by the BES Collaboration in J/ψ radiative decays, combined with the PSI85 experiment of pp → ξ(2230) → KK we argue that because of its very narrow partial decay widths to nn and KK (less than 1 MeV), its large production rate in J/ψ radiative decays (BR(J/ψ → γξ> 2.3×10^-3), and its flavor-symmetric couplings to ππ and KK, the ξ(2230) is very likely to to be a J^PC= (even)⁺⁺ glueball.