Glueballs at physical pion mass

Glueballs are investigated through gluonic operators on two N_(f)=2+1RBC/UKQCD gauge ensembles at the physical pion mass.The statistical errors of glueball correlation functions are considerably reduced through the cluster decomposition error reduction(CDER)method.The Bethe-Salpeter wave functions are obtained for the scalar,tensor,and pseudoscalar glueballs by using spatially extended glueball operators defined through the gauge potential A_(μ)(x)in the Coulomb gauge.These wave functions exhibit similar features of non-relativistic two-gluon systems and are used to optimize the signals of the related correlation functions at the early time regions,where the ground state masses are extracted.These masses are close to those from the quenched approximation and indicate the possible existence of glueballs at the physical point.The resonance feature of glueballs and the mixing with conventional mesons and multi-hadron systems should be considered in a more systematic lattice study.

Two-gluon and trigluon glueballs from dynamical holography QCD

We study the scalar, vector and tensor two-gluon and trigluon glueball spectra in the framework of the 5-dimension dynamical holographic QCD model, where the metric structure is deformed self-consistently by the dilaton field. For comparison, the glueball spectra are also calculated in the hard-wall and soft-wall holographic QCD models. In order to distinguish glueballs with even and odd parities, we introduce a positive and negative coupling between the dilaton field and glueballs, and for higher spin glueballs, we introduce a deformed 5-dimension mass. With this set-up, there is only one free parameter from the quadratic dilaton profile in the dynamical holographic QCD model, which is fixed by the scalar glueball spectra. It is found that the two-gluon glueball spectra produced in the dynamical holographic QCD model are in good agreement with lattice data. Among six trigluon glueballs, the produced masses for 1±- and 2-- are in good agreement with lattice data, and the produced masses for 0--, 0＋- and 2＋- are around 1.5 GeV lighter than lattice results. This result might indicate that the three trigluon glueballs of 0--, 0＋- and 2＋- are dominated by the three-gluon condensate contribution.

Search for J^(PC) = even^(++) glueballs in radiative decay of J/Ψ

Based on the general analysis of decay width and branching ratio of two pseudo scalar meson channels, two sets of discriminants between mesons and glueballs for l = 0, J1PC = even++ un-flavored hadrons with the mass between 1.2 and 2.9 GeV are suggested. Known l = 0, JPC = 2++, f2(l525) particle is discriminated as a typical meson. The way to discriminate new l = 0, JPC = even++ unflavored hadrons is discussed.

Scalar mesons and glueballs in D_p-D_q hard-wall models

We investigate the light scalar mesons and glueballs in the Dp-Dq hard-wall models, including D3-Dq, D4-Dq, and D6-Dq systems. It is found that only in the D4-D6 and D4-Ds hard-wall models are the predicted masses of the clq scalar meson fo scalar glueball consistent with their experimental or lattice results. This indicates that D4-D6 and D4-Ds hard-wall models are the favorite candidates of the realistic holographic QCD model.

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.

Pomeron-Quark Coupling from Charge Conjugation Invariance

Based on the charge conjugation invariance and the vazuum property of the Pomeron, we point out that the commonly used vector vertex of the Pomeron coupling to quarkis incorrect since it contradicts with the Pomeron property. We also claim that the soft Pomeron could be a tensor glueball ξ（2230） with quantum numbers I^GJ^PC = 0^＋2^＋＋ and total decay width Гtot ≌ 100 MeV, which lies on the soft Pomeron trajectory αp = 1.08＋ 0.20t. Therefore, the coupling vertex of the soft Pomeron to quark should be tensorial which is invariant under the charge conjugation and can explaIn why the inadequate vector coupling, γ^μ, of the soft Pomeron to quark is successful in dealing with Pomeron physics.

Pomeron as a Reggeized Tensor Glueball

We study gluonic content of the pomeron and propose that the pomeron could be a reggeized tensor glueball ζ(2230) with quantum numbers IG JPc = 0+2++.This conjecture is examined in high energy proton-proton elastic scattering,and the calculations lend a favorable support to our physical idea.

Reggeon, Pomeron and Glueball, Odderon-Hadron-Hadron Interaction at High Energies—From Regge Theory to Quantum Chromodynamics

Based on analysis of scattering matrix S, and its properties such as analyticity, unitarity, Lorentz invariance, and crossing symmetry relation, the Regge theory was proposed to describe hadron-hadron scattering at high energies before the advent of QCD, and correspondingly a Reggeon concept was born as a mediator of strongly interaction. This theory serves as a successful approach and has explained a great number of experimental data successfully, which proves that the Regge theory can be regarded as a basic theory of hadron interaction at high energies and its validity in many applications. However, as new experimental data come out, we have some difficulties in explaining the data. The new experimental total cross section violates the predictions of Regge theory, which shows that Regge formalism is limited in its applications to high energy data. To understand new experimental measurements, a new exchange theory was consequently born and its mediator is called Pomeron, which has vacuum quantum numbers. The new theory named as Pomeron exchange theory which reproduces the new experimental data of diffractive processes successfully. There are two exchange mediators： Reggeon and Pomeron. Reggeon exchange theory can only produce data at the relatively lower energy region, while Pomeron exchange theory fits the data only at higher-energy region, separately. In order to explain the data in the whole energy region, we propose a Reggeon-Pomeron model to describe high-energy hadron- hadron scattering and other diffractive processes. Although the Reggeon-Pomeron model is successful in describing high-energy hadron-hadron interaction in the whole energy region, it is a phenomenological model. After the advent of QCD, people try to reveal the mystery of the phenomenological theory from QCD since hadron-hadron processes is a strong interaction, which is believed to be described by QCD. According to this point of view, we study the QCD nature of Reggeon and Pomeron. We claim that the Reggeon exchange is an exchange of multigluon,the color singlet gluon bound state. In particular, the Pomeron could be a Reggeized tensor glueball ξ（2230） with mass of 2.23 GeV, quantum numbers I^G, J^PC = 0^＋, 2^＋＋ and decay width of about 100 MeV. The glueball exchange theory reproduces data quite well. Accordingly, we believe that the Odderon, consisting of three Reggeized gluons, and predicted by QCD, should also contribute to hadron-hadron scattering and many other diffractive processes. We search for the Odderon by studying pp and pp elastic scatterings at high energies. Our investigations on the differential cross section dσ/ dt of hadron-hadron scattering at various energies and comparisons with experimental data show that the Odderon plays an essential role in fitting to data. Therefore, we suggest that the measurements should be urgently done in order to confirm the existences of the Odderon and to test QCD.

Thied—Order Approximation of 0^＋＋ Glueball Mass and Wavefunction of （2＋1）—Dimensional SU（3） Lattice Gauge Theory

The random phase approximation is applied to the coupled-cluster expansions of lattice gauge theory (LGT). Using this method, wavefunctions are approximated by linear combination of graphs consisting of only one connected Wilson loop. We study the excited state energy and wavefunction in (2+1)-D SU(3) LGT up to the third order. The glueball mass shows a good scaling behavior.

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.

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.

Quantum study of Foldy-Wouthuysen-Tani theory on lattice

We study here a quantum version of Foldy-Wouthuysen-Tani （FWT） transformation and compare the similarities and differences between the quantum and the classic FWT theories. Then the improvement of action on lattice is discussed. The result shows that it is not necessary to improve the covariant difference along the time direction on lattice. Finally we discuss briefly the structure of physical vacuum and give a model independent of field condensate.

A Lattice Study of the Glueball Spectrum

Glueball spectrum is studied using an improved gluonic action on asymmetric lattices in the pure 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: for the scalar glueball mass and for the tensor glueball.

On a Singular Solution in Higgs Field （Ⅲ）： Condensates and Representation of Certain f0 Mesons＇ Masses

Recently the mass and the basic structure of SM Higgs boson （H^0） have been discussed by the author with obtaining asymptotic solution for the equation of motion of nonlinear Klein-Gordon type partial differential equation. In this paper, we will treat with above in mind： masses of glueball （GB） of ground state and of certain fo mesons, ur, Higgs boson （ur-H^0） which will consist of a number of GBs and/or fo above for respective fullerene structure, a representation of these fo mesons＇ masses by masses of n octet and GB, and transformation of ur-H^0 into H^0.

Quenched Charmed Meson Spectra Using Tadpole Improved Quark Action on Anisotropic Lattices

Charmed meson charmonium spectra are studied with improved quark actions on anisotropic lattices. We measured the pseudo-scalar and vector meson dispersion relations for four lowest lattice momentum modes with quark mass values ranging from the strange quark to charm quark with three different values of gauge coupling β and four different values of bare speed of light v. With the bare speed of light parameter v tuned in a mass-dependent way, we study the mass spectra of D, Ds, ηc, D^＊, D^＊s and J/ψ mesons. The results extrapolated to the continuum limit are compared with the experiment, and a qualitative agreement is found.

1-16 Glueball Quarkonium Mixing in QCD

Despite of the fact that the quark model has been very successful in describing hadron spectrum, there are still some exotic states cannot be explained well. Glueball is one of the most interesting issue among the exotic states.The general wisdom is that QCD must have the glueballs made of gluons. And there are many models have been proposed to describe the physics of glueball[1?5].

1-17 Glueball Physics in QCD

An important issues in hadron spectroscopy is the identification of glueballs. The general wisdom is that QCD must have the glueballs made of gluons. The search for the glueballs has a long history . Several models of glueballs, such as the bag model, flux tube model and constituent model, have been proposed[1??5]. Moreover, the lattice QCD has been able to estimate the mass of the low-lying glueballs[6;7].

Recent results from HERA

After the end of data taking in 2007,the experiments H1 and ZEUS have entered into an intense phase of data analysis.Recent results of this effort on neutral （NC） and charged current （CC） cross sections at high Q 2,the longitudinal structure function F L,inclusive diffraction,heavy flavour production and on searches for glueballs are presented.Also shown are results of a combined analysis on inclusive NC and CC cross sections performed by H1 and ZEUS using HERA-I data.

Abelian-Higgs phase of SU(2) QCD and glueball energy

It is shown that SU（2） QCD admits an dual Abelian-Higgs phase, with a Higgs vacuum of a type-Ⅱ superconductor. This is done by using a connection decomposition for the gluon field and the random-direction approximation. Using a bag picture with soft wall, we presented a calculational procedure for the glueball energy based on the recent proof for wall-vortices [Nucl. Phys. B 741（2006）1].

Scalar glueball in a soft-wall model of AdS/QCD

The scalar glueball is investigated in a soft-wall model of AdS/QCD. Constraints of the mass of the scalar glueball are given through an analysis of a relation between the bulk mass and the anomalous dimension. The mass of the ground scalar glueball is located at 0.96＋-0.07 ＋0.04 GeV 〈 MG 〈 1.36＋0.05 -0.10 GeV. In terms of a background dilaton field θ（z）= cz2, the two-point correlation function for the scalar gluon operator is obtained. The two-point correlation function at A=4 gives a different behavior compared with the one in QCD.