Light-front holographic QCD with generic dilaton profile

We generalize the soft-wall and hard-wall models to a light-front holographic QCD model with a generic dilaton profile. The effective potential induced by a higher power dilaton profile is interpreted as a stronger color confinement at long distance, and it gradually evolves to the hard-wall model when the power increases to infinity. As an application, we investigate the exotic meson states recently discovered in experiments in the generic soft-wall model with a higher power dilaton profile, and the results are in agreement with the spectra of the exotic mesons. Our calculation indicates a weaker interaction at short distance and a stronger interaction at large distance for the components in the exotic mesons. The generic dilaton profile deserves further scrutiny for understanding the strong interaction and for applications.

Figure 1

The generic dilaton profile with different power $p$.

Figure 2

The effective potentials induced by different dilaton profiles.

Figure 3

The mass spectra of the $Z$ mesons. The solid curve is the model results with $\kappa =223\mathrm{MeV}$. The data are taken from Refs. [16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26].