Structure of Vector Mesons in Holographic Model with Linear Confinement

TL;DR

This paper investigates the wave functions and form factors of vector mesons within a holographic QCD model featuring a smooth confinement wall, revealing perfect vector meson dominance and providing detailed radius calculations.

Contribution

It introduces a formalism using wave functions similar to quantum oscillators and analyzes vector meson properties in a holographic model with linear confinement.

Findings

The rho-meson form factor exhibits perfect vector meson dominance.

The rho-meson's electric radius is calculated as 0.655 fm^2.

Higher excited states' radii increase logarithmically with excitation number.

Abstract

Wave functions and form factors of vector mesons are investigated in the holographic dual model of QCD with a smooth oscillator-like wall. We introduce wave functions conjugate to solutions of the 5D equation of motion and develop a formalism based on these wave functions, which are very similar to those of a quantum-mechanical oscillator. For the lowest bound state (rho-meson), we show that, in this model, the basic elastic form factor exhibits the perfect vector meson dominance, i.e., it is given by the rho-pole contribution alone. The electric radius of the rho-meson is calculated, <r^2_rho>_C = 0.655 fm^2, which is larger than in case of the hard-wall cutoff. The squared radii of higher excited states are found to increase logarithmically rather than linearly with the radial excitation number. We calculate the coupling constant f_rho and find that the experimental value is closer to that calculated in the hard-wall model.