The Curzon singularity. II: Global picture

A new coordinate system is presented for the Curzon metric such that a class of incomplete geodesics are extendible both in the past and the future into regions of flat space. All other incomplete geodesics terminate at the (infinite curvature) singularity, which appears as a ring with finite radius and is naked. The Curzon solution emerges in this picture as a peculiar kind of sandwich wave. This and other physical interpretations such as a possible collapse scenario are discussed.Commonwealth Postgraduate Research Award (Australia); Zonta International Amelia Earhart Fellow (U.S.A.); A.F.U.W.—Victoria Centenary Scholarship.     

Dynamic facilitation picture of a higher-order glass singularity

We show that facilitated spin mixtures with a tunable facilitation reproduce, on a Bethe lattice, the simplest higher-order singularity scenario predicted by the mode-coupling theory (MCT) of liquid-glass transition. Depending on the facilitation strength, they yield either a discontinuous glass transition or a continuous one, with no underlying thermodynamic singularity. Similar results are obtained for facilitated spin models on a diluted Bethe lattice. The mechanism of dynamical arrest in these systems can be interpreted in terms of bootstrap and standard percolation and corresponds to a crossover from a compact to a fractal structure of the incipient spanning cluster of frozen spins. Theoretical and numerical simulation results are fully consistent with MCT predictions.     

坡密子和胶子球

讨论了高能强子 -强子散射过程中的坡密子以及坡密子的 QCD内容 .认为坡密子有可能就是具有量子数 IG=0 + ,JPC=2 + +的张量胶子球 ξ( 2 2 30 ) .用雷其化胶子球模型计算了高能质子 -质子散射截面和坡密子 -核子的耦合参数 β.理论结果与实验的要求一致. The pomeron in high energy hadron hadron scattering as well as the QCD nature of the pomeron are discussed. We claimed that the pomeron may be the tenser glueball ξ(2 230) with quantum number I G =0 +, J PC =2 ++ . Under this reggeized glueball model the cross section of high energy proton proton scattering and the coupling parameter of the pomeron nucleon, β , are calculated. The theoretical results of the present model are in good agreement with experimental data.     

Glueball string models,rotational states,and regge trajectories

A glueball model that describes excited states of glueballs and other exotic hadrons and which has the form of a closed string that features pointlike masses simulating gluons is considered. Rotational states are studied for this model. Their structure proves to be nontrivial. These states are classified, and their frequency spectrum and physical properties, including the energy and angular momentum, are determined with allowance for spin corrections. The corresponding Regge trajectories characterized by a specific set of slopes are used to describe glueball states.     

Glueball masses and the loop-loop correlation functions

We analyse the pure gauge lattice QCD by measuring loop-loop correlation functions on a 12³×32 lattice at β=5.9. We select a set of operators given by the smearing procedure. We obtain a good estimate of the mass of the 0⁺⁺ state and for the string tension, and upper bounds for the masses of the 2⁺⁺ and the 1⁺⁻ states.     

How to Detect the Lightest Glueball

Journal of Experimental and Theoretical Physics - We suggest a procedure for detecting the lightest glueball in a head-on collision of photons whose center-of-mass energy is in the range...     

Current Situation on the Glueball Research

The current situation on the glueball research is reviewed in this paper.The emphases are some qualitative guidances to identify the glueball and several possible candidate states for the glueball which have been discovered in the experiments.     

A comparative analysis of Mesonic, Baryonic and Glueball Regge trajectories

We present a comparative analysis of mesonic, baryonic and Glueball Regge trajectories based on different parameters. The different inbuilt compositions of the three seem to serve as a basis for their individual identities. We discuss features such as crossed channel forces, signature, string models and also the dependence of the slope of the mesons and baryons on the fine structure constant. We infer that inspite of various inherent similarities, these three Regge trajectories have some distinctive features which serve as a basis for their identification.     

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.     

Glueball spectrum and Pomeron in the Wilson loop approach

Using a nonperturbative method based on the asymptotic behavior of Wilson loops, we calculate the masses of glueballs and the corresponding Regge trajectories. The only input is the string tension fixed by the meson Regge slope, while perturbative contributions to spin splittings are defined by standard α_s values. The masses of the lowest glueball states are in a perfect agreement with lattice results. The leading glueball trajectory, which is associated with the Pomeron is discussed in detail, and its mixing with f and f′ trajectories is taken into account.     

Gluonic Origin and Glueball Nature of Pomeron

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Gluonic Origin and Glueball Nature of Pomeron

The Pomeron-nucleon coupling vertex is theoretically derived from the fundamental theory of strong interaction QCD. The empirical vertex βγ^μF1 （t） used commonly in diffractive processes with a coupling strength β = 6.0 GeV^-1 is initially obtained from QCD theoretically. Our study not only reproduces the Pomeron-nucleon coupling from QCD but also clearly shows the gluonlc origin and glueball nature of Pomeron, which is a longstanding puzzle. From this investigation, we claim that Pomeron can be regarded as a Reggeized tensor glueball ζ（2230） with quantum numbers of I^GJ^PC = 0＋2＋＋. Since the tensor glueball ζ（2230） lies on the Pomeron trajectory αp（t = Mζ^2） = 2, the longstanding puzzle that no physical particle lies on the Pomeron trajectory, αp（t） = 1.08 ＋ 0.20 GeV^-2 .t, seems to be solved.     

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.     

On vacuum density,the initial singularity and dark energy

Standard cosmology poses a number of important questions. Apart from its singular origin, it possesses early and late accelerating phases required to account for observations. The vacuum energy has been considered as a possible way to resolve some of these questions. The vacuum energy density induced by free fields in an early de Sitter phase has earlier been estimated to be proportional to H ⁴, while more recently it has been suggested that the QCD condensate induces a term proportional to H at late times. These results have been employed in models which are non-singular and inflationary at early times and accelerating at late times. Here we cast these models in terms of scalar fields and study the corresponding spectrum of primordial perturbations. At early times the spectrum is found to be not scale-invariant, thus implying that slow-roll inflation is still required after the phase transition induced by the vacuum. At late times the corresponding scalar-field potential is harmonic, with a mass of the order of the Hubble scale, a result that may be understood in the light of the holographic conjecture.