Two-gluon and trigluon glueballs from dynamical holography QCD

Abstract

We study the scalar, vector and tensor two-gluon and trigluon glueball spectra in the framework of 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 the 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 three-gluon condensate contribution.

Exotic glueball 0±− states in QCD sum rules

“…As one can see, there is a rather good stability plateau for both quantities which is ensured by the condition in Eq. (16). The masses and decay constants estimated with the higher values of k = 1, 2, 3 are in agreement with the k = 0 case.…”

“…The fiducial intervals have been defined through the conditions Eqs. (14,15,16 This condition puts limits on the continuum threshold value s 0 . The conditions Eqs.…”

“…The conditions Eqs. (14,15,16) define the fiducial set of (M 2 , s 0 )-values. Finally we define the prediction for the mass and the decay constant as an average of the maximal and the minimal values on the fiducial interval of M 2 with the fixed central value of threshold given in the last column of Table I:…”

“…The first two errors, which originate from OPE truncation and continuum modeling, are defined by variation of results on the fiducial (M 2 , s 0 )-set that represents the conditions Eqs. (14,15,16). The variation of the G 3 condensate comes from [42,43] (see Eq.…”

Effective holographic models for QCD: Glueball spectrum and trace anomaly

“…This in turn leads to a nonzero gluon condensate and confinement. A particularly interesting proposal was considered recently in [26,27] where an analytic function was used to interpolate the dilaton between a quartic form in the UV and a quadratic form in the IR. However, as explained before, a quartic dilaton in the UV necessary leads to an unacceptable massless mode in the scalar sector of glueballs [2].…”