Logarithmic correction in the deformed ${\rm AdS}_5$ model to produce the heavy quark potential and QCD beta function

TL;DR

This paper explores a deformed AdS5 holographic QCD model with quadratic and logarithmic corrections to better fit the heavy quark potential and QCD beta function, analyzing the effects of these corrections on the dilaton potential and infrared behavior.

Contribution

It introduces a deformed AdS5 model with specific corrections and studies their impact on heavy quark potential and QCD beta function, proposing a simplified model with fewer parameters.

Findings

Quadratic correction with negative sigma favors fitting heavy quark potential.

Positive sigma leads to an infrared fixed point in the beta function.

Logarithmic correction accurately reproduces the Cornell potential and QCD beta function.

Abstract

We stude the \textit{holographic} QCD model which contains a quadratic term $ -\sigma z^2$ and a logarithmic term $-c_0\log[(z_{IR}-z)/z_{IR}]$ with an explicit infrared cut-off $z_{IR}$ in the deformed ${\rm AdS}_5$ warp factor. We investigate the heavy quark potential for three cases, i.e, with only quadratic correction, with both quadratic and logarithmic corrections and with only logarithmic correction. We solve the dilaton field and dilation potential from the Einstein equation, and investigate the corresponding beta function in the G{\"u}rsoy -Kiritsis-Nitti (GKN) framework. Our studies show that in the case with only quadratic correction, a negative $\sigma$ or the Andreev-Zakharov model is favored to fit the heavy quark potential and to produce the QCD beta-function at 2-loop level, however, the dilaton potential is unbounded in infrared regime. One interesting observing for the case of positive $\sigma$, or the soft-wall ${\rm AdS}_5$ model is that the corresponding beta-function exists an infrared fixed point. In the case with only logarithmic correction, the heavy quark Cornell potential can be fitted very well, the corresponding beta-function agrees with the QCD beta-function at 2-loop level reasonably well, and the dilaton potential is bounded from below in infrared. At the end, we propose a more compact model which has only logarithmic correction in the deformed warp factor and has less free parameters.