Confinement and pseudoscalar glueball spectrum in the 2+1D QCD-like theory from the non-SUSY D2 brane

Here we study two important properties of 2 + 1-dimensional QCD-confinement and pseudoscalar glueball spectrum- with holographic approach. We consider the low energy decoupled geometry of the isotropic non-supersymmetric D2 brane. We find the corresponding gauge theory is similar to the 2 + 1-dimensional Yang-Mills (YM) theory with the running coupling lambda(2). At the extremal limit (i.e., Bogomol'nyi-Prasad-Sommerfield limit), this gauge theory reduces to the super-YM theory. From the Nambu-Goto action of a test string, the potential of a Q-(Q) over bar pair located on the boundary is calculated. At large Q-(Q) over bar separation, it gives the tension s of the QCD flux tube. The parametric dependence of s is shown pictorially. It is found that sigma is a monotonically increasing function of the effective coupling lambda(2). In comparison, root sigma/g(YM)(2)N(c) is found to match accurately with the previous results. In the next part, we consider fluctuation of the axion field in the aforementioned gravity background. From the linearized field equation of the fluctuation, we calculate the mass spectrum of 0(-+) numerically using theWentzel-KramersBrillouin approximation. The pseudoscalar mass is found to be related to the string tension approximately as M-0(-+)/root sigma approximate to 3(n+3) for first three energy states, n = 0, 1, 2.

Automated summary

This study investigates important properties of 2 + 1-dimensional QCD-confinement and pseudoscalar glueball spectrum using holographic approach. It reveals correlations between gauge theory and string tension, as well as the mass spectrum of pseudoscalar fluctuations in gravity background.