Holographic QCD beyond the leading order

TL;DR

This paper extends holographic QCD models by including dimension-6 operators, leading to improved predictions of meson decay processes and electromagnetic properties that align well with experimental data.

Contribution

It introduces dimension-6 operators into the holographic QCD framework, enhancing the model's accuracy in describing meson dynamics beyond the leading order.

Findings

Non-zero branching ratio for $a_1 o ho \, \pi \gamma$ decay.

Improved electromagnetic form factor and charge radius predictions for charged pions.

Results show better agreement with experimental measurements.

Abstract

We consider a holographic QCD model for light mesons beyond the leading order in the context of 5-dim gauged linear sigma model on the interval in the AdS$_5$ space. We include two dimension-6 operators in addition to the canonical bulk kinetic terms, and study chiral dynamics of $\pi$, $\rho$, $a_1$ and some of their KK modes. As novel features of dim-6 operators, we get non-vanishing Br$(a_1 \to \pi \gamma)$, the electromagnetic form factor and the charge radius of a charged pion, which improve the leading order results significantly and agree well with the experimental results.