Confront Holographic QCD with Regge Trajectories of vectors and axial-vectors

Abstract

We derive the general 5-dimension metric structure of the $Dp-Dq$ system in type II superstring theory, and demonstrate the physical meaning of the parameters characterizing the 5-dimension metric structure of the \textit{holographic} QCD model by relating them to the parameters describing Regge trajectories. By matching the spectra of vector mesons ${\rho }_1$ with deformed $Dp-Dq$ soft-wall model, we find that the spectra of vector mesons ${\rho }_1$ can be described very well in the soft-wall $D3-Dq$ model, i.e, $Ad{S}_5$ soft-wall model. We then investigate how well the $Ad{S}_5$ soft-wall model can describe the Regge trajectory of axial-vector mesons $a_1$. We find that the constant component of the 5-dimension mass square of axial-vector mesons plays an efficient role to realize the chiral symmetry breaking in the vacuum, and a small negative $z^4$ correction in the 5-dimension mass square is helpful to realize the chiral symmetry restoration in high excitation states.

Comments: 9 pages, 3 figure and 3 tables, one section added